A Chronology of 

Middle Missouri Plains 

Village Sites

By Craig M. Johnson

with contributions by

Stanley A. Ahler, Herbert Haas, and Georges Bonani

Smithsonian Institution

Scholarly Press

Smithsonian Institution

Scholarly Press

smithsonian contributions to history and technology • number 57

Proceedings of the First 

International Symposium 

on Analytical Methods 

in Philately

Edited by

Thomas Lera, John H. Barwis,

and David L. Herendeen
Series Publications of the Smithsonian Institution

Emphasis upon publication as a means of “diffusing knowledge” was 

expressed by the first Secretary of the Smithsonian. In his formal plan 

for the Institution, Joseph Henry outlined a program that included 

the following statement: “It is proposed to publish a series of reports, 

giving an account of the new discoveries in science, and of the changes 

made from year to year in all branches of knowledge.” This theme of 

basic research has been adhered to through the years by thousands of 

titles issued in series publications under the Smithsonian imprint, commencing with Smithsonian Contributions to Knowledge in 1848 and 

continuing with the following active series: 

Smithsonian Contributions to Anthropology

Smithsonian Contributions to Botany

Smithsonian Contributions to History and Technology

Smithsonian Contributions to the Marine Sciences

Smithsonian Contributions to Museum Conservation

Smithsonian Contributions to Paleobiology

Smithsonian Contributions to Zoology

In these series, the Institution publishes small papers and full-scale 

monographs that report on the research and collections of its various 

museums and bureaus. The Smithsonian Contributions Series are 

distributed via mailing lists to libraries, universities, and similar institutions throughout the world. 

Manuscripts submitted for series publication are received by the 

Smithsonian Institution Scholarly Press from authors with direct affiliation with the various Smithsonian museums or bureaus and are subject 

to peer review and review for compliance with manuscript preparation 

guidelines. General requirements for manuscript preparation are on the 

inside back cover of printed volumes. For detailed submissions requirements and to review the “Manuscript Preparation and Style Guide for 

Authors,” visit the Submissions page at www.scholarlypress.si.edu.
smithsonian contributions to history and technology • number 57

Proceedings of the First 

International Symposium 

on Analytical Methods 

in Philately

Edited by

Thomas Lera, John H. Barwis,

and David L. Herendeen

washington d.c.

2013
ABSTRACT

Lera, Thomas, John H. Barwis, and David L. Herendeen. Proceedings of the First International Symposium 

on Analytical Methods in Philately. Smithsonian Contributions to History and Technology, number 

57, x + 122 pages, 111 figures, 22 tables, 2013.—This publication contains papers presented at the First 

International Symposium on Analytical Methods in Philately, hosted by the National Postal Museum in 

November 2012. Readers will find insights to research methods used across the entire spectrum of philatelic 

interests, from composition and physical characteristics of paper, to the chemistry and mineralogy of printing 

ink, to determining the genuineness of stamps, overprints, and the uses of adhesives on cover. Some of these 

projects were funded in part by the Institute for Analytical Philately and the National Postal Museum.

Cover images, from left to right: Detail of 1941 Republic of Panama Air Mail Stamp (Scott C6B); Figure 12 

of “A Scientific Analysis of the First Issues of Chile 1853–1862;” and Figure 3 of “Infrared Spectroscopic and 

X-Ray Diffraction Studies of the Typographed Confederate 5¢ Stamps.”

Published by SMITHSONIAN INSTITUTION SCHOLARLY PRESS

P.O. Box 37012, MRC 957

Washington, D.C. 20013-7012

www.scholarlypress.si.edu

Compilation copyright © 2013 Smithsonian Institution

The rights to text and images in this publication, including cover and interior designs, are owned either by the Smithsonian Institution, by contributing authors, or by third parties. Fair use of materials is permitted for personal, educational, 

or noncommercial purposes. Users must cite author and source of content, must not alter or modify copyrighted content, 

and must comply with all other terms or restrictions that may be applicable. Users are responsible for securing permission 

from a rights holder for any other use.

Library of Congress Cataloging-in-Publication Data

International Symposium on Analytical Methods in Philately (1st : 2012 : Washington, DC)

Proceedings of the First International Symposium On Analytical Methods In Philately / edited by Thomas Lera, 

John H. Barwis, and David L. Herendeen.

 pages cm — (Smithsonian contributions to history and technology, ISSN 1948-5999 ; number 57)

“This publication contains papers presented at the First International Symposium on Analytical Methods in Philately, 

hosted by the National Postal Museum in November 2012.”

Includes bibliographical references.

1. Stamp collecting—Congresses. 2. Postage stamps—Expertising—Congresses. 3. Postage stamps—Forgeries—

Congresses. I. Lera, Thomas M. II. Barwis, John H. III. Herendeen, David L., –2013. IV. Title.

HE6189.I58 2012

769.56—dc23

2013020554

ISSN: 1948-5999 (print); 1948-6006 (online)

The paper used in this publication meets the minimum requirements of the American National Standard for 

Permanence of Paper for Printed Library Materials Z39.48–1992.
Contents

WELCOME LETTER v

Allen Kane

PREFACE vii

John H. Barwis and Thomas Lera

DAVID L. HERENDEEN, 1946–2013 ix

John H. Barwis and Thomas Lera

Keynote Address: The Place for New Tools in Forensic Philately 1

David R. Beech 

Paper Characteristics of U.S. 3¢ Stamps, 1870–1881 5

John H. Barwis

A Scientific Analysis of the First Issues of Chile 1853–1862, London Printing 19

Thomas Lera, Jennifer Giaccai, and Nicole Little

Documenting Science in Philatelic Literature: A New Perspective 35

David L. Herendeen

Infrared Spectroscopic and X-Ray Diffraction Studies of the Typographed 

Confederate 5¢ Stamps 47

Harry G. Brittain

Forensic Analysis of Great Britain 1858–1879 1d Plate 77 Stamps on Cover 57

Abed H. Najjar

The U.S. 1851 3¢ Stamp: Color, Chemistry, and Changes 71

James A. Allen and Thomas Lera

Analysis of Postage Stamps by Proton-Induced X-Ray Emission 

Spectrometry 83

Thomas E. Gill

Statistical Estimates of Rare Stamp Populations 91

David L. Herendeen and Gary C. White

Reflectance Spectroscopy of Colored Overprints 101

Lyman R. Caswell
i v • smithsonian contributions to history and technology

ABSTRACTS

A Comparative Study of Security Measures Used by Stamp Printers 109

Garfield Portch and Charles J. G. Verge

New Ways of Looking at Prephilatelic Inks 111

Dieter Bortfeldt

A Layman’s Forensic Adventure 113

Roland H. Cipolla II

SCHOLARSHIPS AT THE SMITHSONIAN NATIONAL 

POSTAL MUSEUM 115

APPLICATION FOR AN IAP RESEARCH GRANT 117

THE SYMPOSIUM FEEDBACK SESSION 119
Welcome Letter

June 1, 2013

It is my great pleasure to present the Proceedings of the First International Symposium on Analytical Methods in Philately. The Smithsonian National Postal Museum 

(NPM) hosted this premier meeting on 12–14 November 2012 in the Winton M. Blount 

Center for Postal Studies. 

This international symposium was, to our knowledge, the first ever held. It offered 

an opportunity for interested philatelists and scientists to get together, share their methodologies, highlight new technologies, and provide long-term, wide-ranging benefits to 

all aspects of philately and helped set the course for future forensic analyses in the philatelic arena. Our close working relationship with the Institute for Analytical Philately, Inc. 

was a huge plus because the NPM allowed philatelists to use state-of-the-art equipment 

for their advanced research efforts.

The success of the symposium was due in large part to David Herendeen, president 

and founder of the Institute for Analytic Philately, Inc., and Thomas Lera, NPM Winton 

M. Blount Research Chair, as well as the speakers, the demonstrations, and the more 

than 50 attendees. Special thanks go to Elizabeth Simmonds, NPM event coordinator. 

Without her efforts, the symposium would not have been as great of a success.

If you enjoy these papers as much as I hope you will, please continue to support 

the National Postal Museum, the Institute for Analytical Philately, Inc., and future 

symposiums.

Allan Kane

Director, National Postal Museum

Preface

The Institute for Analytical Philately, Inc. (IAP) was formed in 2010 as a philanthropic, nonprofit corporation dedicated to deepening the understanding of 

philatelic materials through the use of scientific technology and publication of 

experimental results. The support IAP provides can be tailored to the needs of any philatelist, from those with no scientific background to those with advanced degrees in science 

or engineering.

IAP grants typically range from $2,000 to $4,000 and are intended to help fund 

travel, lodging, and laboratory use. Additional funding may be available through cost 

sharing with alliance members, who can also provide advice on previous work done in 

a particular area or help in conceiving and planning a research effort. Current alliance 

partners include the Smithsonian National Postal Museum (NPM), the U.S. Philatelic 

Classics Society, Inc., the Confederate Stamp Alliance, the Vincent G. Greene Philatelic 

Research Foundation (Canada), and the Philatelic Foundation. Detailed information on 

grants and NPM scholarships can be found on page 115.

Researchers may conduct their work anywhere they choose but are encouraged to 

take advantage of the facilities and expertise available at IAP’s centers of excellence, 

where they will find state-of-the-art equipment and experienced advisors like at the 

Smithsonian National Postal Museum, where a broad range of equipment and expert 

guidance is available.

This book contains papers presented at the First International Symposium on Analytical Methods in Philately, hosted by the National Postal Museum in November 2012. 

Readers will find insights to research methods used across the entire spectrum of philatelic interests, from the composition and physical characteristics of paper to the chemistry 

and mineralogy of printing ink to determining the genuineness of stamps and overprints, 

and to the uses of adhesives on cover. Some of these projects were funded in part by IAP 

and NPM. Some of the presenters have already had their research published, so for those 

presentations we have included abstracts and citations.

The symposium also included one day of hands-on training and demonstrations 

using equipment from the NPM research lab led by manufacturers’ representatives. 

We plan to host another international symposium, the timing of which will depend 

on the pace and volume of research conducted over the next one to two years. In the 

meantime, we encourage you to get involved in investigating philatelic mysteries. For 

more information about IAP visit www.analyticalphilately.org, and for information on 

the NPM visit www.postalmuseum.si.edu.

Dr. John H. Barwis, FRPSL Thomas Lera, FRPSL

Institute for Analytical Philately, Smithsonian National Postal Museum,

President Research Chair

David L. Herendeen, 

1946–2013

David L. Herendeen, founder and first president of the Institute for Analytical 

Philately, died suddenly on 4 January 2013 in Las Vegas. David was a stamp 

collector since childhood and specialized in worldwide postage-due stamps and 

postal history for more than 35 years. His exhibits of British Empire and French community postage-dues won many national gold medals, grand awards, and two international 

gold medals. He held many positions in organized philately, including president of the 

France and Colonies Philatelic Society (2004–2007), first vice president and board member of the American Philatelic Congress (1997–2010), and vice president (2003–2006) 

and board member of the American Association of Philatelic Exhibitors (2000–2010). 

He was both a nationally accredited and a chief judge, serving in these capacities for 

more than 15 years. He was also an active writer and published major research articles 

in many publications, including The London Philatelist, The Collectors Club Philatelist, 

and The Congress Books. Additionally, he was an editor of the France and Colonies Philatelist (2007–2013) and the British Caribbean Philatelic Journal (1997–1999). His book 

The Parcel Post Stamps of the Ivory Coast received a gold medal at Stampshow 2001.

David retired as a senior executive of an engineering and software consulting company after a 35-year career performing and managing government-related research and 

development activities. He held a degree in mathematics and computer science from the 

University of California, Los Angeles (UCLA) and took numerous graduate and career 

development courses at the State University of New York, UCLA, and the California 

Institute of Technology.

David’s interest and experience in engineering and mathematics expressed themselves in his philatelic studies and ultimately led to his suggesting the idea for the IAP 

to a small group of like-minded colleagues. His belief that analytical methods held wide 

interest among philatelists was quickly validated when nearly 100 people joined the new 

organization within a year of its launch. We are committed to continuing his work.

David was a man of conviction, honor, and principles. He was passionate about 

knowledge and was inquisitive about much of what makes our life as stamp collectors 

worth living. He will be missed by all who knew him and who shared his laughter and 

joy of philatelic pursuits. 

John H. Barwis

Thomas Lera

Keynote Address: 

The Place for New Tools in Forensic Philately

David R. Beech

INTRODUCTION

This paper relates to my realization, reinforced by my access to the developments 

at the British Library for the conservation and preservation of rare documents, that certain philatelic problems could be better solved or understood by the quantitative methods traditionally associated with the physical sciences than by the taxonomical methods 

traditionally associated with the biological sciences. In 2001, I worked with University 

College London on a project to use spectrographic analysis to study the very rare (and 

valuable) “Post Office” Mauritius stamps of 1847, developing definitive information 

about the inks used and establishing a basis for a similar study in 2002 that evaluated the 

1851–1852 so-called Grinnell Missionary stamps of Hawaii.

My views and observations on the expertization in conjunction with the recent development of advanced methods (some of which will be discussed in detail in the papers 

presented) for performing various analyses on postage stamps and other postal matter 

are largely based on supporting the Expert Committee of the Royal Philatelic Society 

London. It should be noted that it is not the purview of the Institute for Analytical Philately, Inc., the Smithsonian National Postal Museum, or the British Library to provide 

expertization services.

A NEW BEGINNING

It is almost impossible to overestimate the importance of the First International Symposium on Analytical Methods in Philately held in November 2012 at the Smithsonian 

National Postal Museum, Washington, D.C. This event was organized by the Institute for 

Analytical Philately, Inc. As the institute is comparatively new, having been established in 

2009, its first public meeting is a key opportunity to establish its credentials along with a 

number of principles that will set the scene for the future.

I am pleased to have had the opportunity to present the keynote address, and I 

intend to touch on several important aspects of analytical philately and its application 

to expertization. While a taxonomical analysis, associated with the “English school” of 

philately, may easily afford the detection of “bogus” issues, quantitative analysis for the 

detection of forgeries, associated with the “French school,” has long been hampered by 

the cost and availability of appropriate technologies. But, to a certain extent, that is no 

longer the case because over the last decade the availability and ease of use of nondestructive analytical equipment has grown while its cost has decreased dramatically. Some 

David R. Beech, Royal Philatelic Society London, 41 Devonshire Place, London, W1G 6JY, 

UK. Correspondence: DRBeech@btinternet.com. 

Manuscript received 10 April 2013; accepted 26 

April 2013.
2 • smithsonian contributions to history and technology

of this equipment is now within the grasp of major museums 

and expertizing bodies and can be used to disclose sophisticated 

forgeries.

In the earliest days of philately, the English school emphasized the postage stamp design, ignoring differences in paper, 

shade, perforation, watermark, etc. The French school required 

some close study and some tools, beginning with the magnifying 

glass. Later came accurate measurement, perforation gauges, and 

watermark fluid. More high tech methods occurred when ultraviolet light was deployed to detect alterations or the removal of 

postal markings. During the 1960s, Cheavin (1885–1968) used 

X-rays to detect altered stamps (Cheavin, 1950). In recent years 

it has been suggested that he was also making the altered stamps 

about which he wrote.

My involvement with more advanced analytical methods 

dates from 2001 when the British Library started working with 

Professor Clark and his student colleagues at University College 

London (Clark, 1999). They were examining pigments on manuscripts and early printed books, maps, and other paper artifacts 

by Raman spectroscopy.

One project was to look at the inks on Mauritius 1847 1d 

and 2d “Post Office” issue (see Figure 1 for one of the five known 

covers with the 1d stamp) and of the 1858–1862 Britannia issue 

using examples in the Tapling Collection.1

 We were able to determine the pigments involved (Chaplin et al., 2004) and thus 

established a standard against which others can be judged (and 

have been judged, for the 1847 issue) by the Expert Committee 

of the Royal Philatelic Society London.

During 2002 I became involved in the question of the expertization of the Hawaii 1851–1852 Grinnell Missionary stamps. 

Earlier examinations had proved inconclusive (Chaplin et al., 

2002), but, using Raman spectroscopy to compare the stamps in 

the Tapling Collection, known by their provenance to be genuine 

(Figure 2), with the Grinnell examples that were the property of 

the Shattuck family, the Expert Committee of the Royal Philatelic Society London determined that the Grinnells were forgeries 

(Pearson, 2006).

I have since been involved in other Raman work with Professor Clark, and in due course a paper about aspects of the 

Chalon issues of New Zealand will appear.

Analytical philately is the use of chemical, physical, mathematical, or other quantitative scientific methods to establish the 

facts in any philatelic matter. The facts, or evidence, are examined, with the end result of establishing the truth about a theory, 

the color, or the genuineness of a philatelic item. This may not 

be so easy.

The expertization of philatelic material has always been of 

the first importance. Publications on the detection of forgeries 

began to appear in the 1860s. Expertization took an organizational advance when in 1894 the Philatelic Society, London—

now the Royal Philatelic Society London—formed the first 

expert committee. I have come to see such committees as “the 

Figure 1. The Post Office Mauritius issue of 1847 (the Tapling Collection, Courtesy British Library).
number 57 • 3

courts of law” in philately, and, while they only give opinions, 

they represent the best we have in establishing the truth.

If committees or expertizers are the philatelic courts of law, 

what standard of proof is required for a clear verdict? Does science offer absolute proof? Can an argument of probabilities 

prove sufficient? What are the possibilities of misinterpretation? Perhaps this symposium will help to answer some of these 

questions.

Philatelic expertization is probably at something of a crossroads as new technologies have become available for the application of scientific methods. The identification of shades, a 

longtime problem, might be much improved. (I think that the 

visual discrimination of shades of color is insufficient without an 

analysis of the pigments and their prospects for change.) With 

the need of expertizers to embrace scientific analysis, will single 

experts, common in continental Europe, still be able to function 

with what might be the new standards of evidence? I have suggested in a paper (Beech, 2008) that perhaps in the near future 

an expert certificate should be

• an opinion as to genuineness;

• a record of its provenance (for sufficient rarities); and

• a record of any treatments used in conservation, with 

a full photographic record and a record of any special 

scientific analyses, such as examinations by colorimetric 

methods and Raman spectroscopy.

If items submitted for opinion need any subsequent scientific analysis, who will do the work and how will it be paid for? 

How will those who run expertizing organizations be confident 

of scientific advice? As with the expertization of the Hawaii 

1851–1852 Grinnell stamps by the Expert Committee of the 

Royal Philatelic Society London in 2006, some text in addition 

to a certificate simply stating “genuine” or “forgery” will be required. It must provide the evidence and technical details, if only 

for such scientific work to be repeated independently.

CONCLUSIONS

Much opinion today is based on evidence of earlier technologies, which the author’s Grinnell work showed were not 

sufficient to distinguish the status of the Tapling and Grinnell 

Hawaiian Missionaries. The challenge to expertizers is to have a 

good understanding of the new techniques of science. The philatelic expertizer must have a good understanding of taxonomical and quantitative methods and the philatelic background of 

the items under consideration. But how is experience to be balanced with science? It seems clear scientific methods have much 

to offer, with this symposium being a clear learning ground, but 

we must use judgment in arriving at our final determinations. 

NOTE

1. The Tapling Collection was formed by the wealthy Victorian businessman 

Thomas Keay Tapling, MP. It was bequeathed on his early death at the age of 35 

in 1891. The collection is unrivalled in that it is the only major one formed during 

the nineteenth century that is still intact and contains almost all issues of postage 

stamps and postal stationery as well as most of the rarities issued up to 1890; 

Figure 2. The Hawaiian Missionary stamps of 1851 (the Tapling Collection, Courtesy British Library).
4 • smithsonian contributions to history and technology

see http://www.bl.uk/reshelp/findhelprestype/philatelic/philateliccollections/articles

/articletapling/articlestapling.html (accessed 1 November 2012).

REFERENCES

Beech, D. R. 2008. Philatelic Conservation—Restoration. Fakes, Forgeries, Experts, 11:76–78.

Chaplin, T. D., R. J. H. Clark, and D. Beech. 2002. Comparison of Genuine, 

(1851–52 AD) and Forged or Reproduction Hawaiian Stamps Using Raman 

Microscopy. Journal of Raman Spectroscopy, 33:424–428. 

Chaplin, T. D., A. Jurado-Lopez, R. J. H. Clark, and D. Beech. 2004. Identification by Raman Microscopy of Pigments on Early Postage Stamps: Distinction 

between Original 1847 and 1858–1862, Forged and Reproduction Postage 

Stamps of Mauritius. Journal of Raman Spectroscopy, 35:600–604.

Cheavin, W. H. S. 1950. X-Rays Do It Again. A Dangerous Forgery of the 24 Cent 

Inverted Centre U.S. Air Mail Exposed. Philately, 3:54–55.

Clark, R. J. H. 1999. Raman Microscopy: Sensitive Probe of Pigments on Manuscripts, Paintings and Other Artefacts. Journal of Molecular Structure, 480–

481:15–20. http://dx.doi.org/10.1016/S0022-2860(98)00649-8. 

Pearson, P. 2006. The Investigation of the Grinnell Hawaiian Missionaries by the 

Expert Committee of the Royal Philatelic Society London. London: RPSL.
Paper Characteristics of U.S. 3¢ Stamps, 

1870–1881

John H. Barwis

ABSTRACT. This paper describes laboratory research conducted on the United States 

3¢ issues of 1870, 1873, 1879, and 1881 (Scott catalog numbers 147, 158, 184, and 207, 

respectively) to characterize the types of paper used by the three private printing companies that produced these stamps. The goal of this work was to quantitatively determine 

how many different papers each company used and which of these papers may have 

been used by more than one company. Analyses included measurement of paper thickness, fiber length and deformation, bending resistance, permeability, and sizing chemistry. 

The results demonstrate that combinations of these variables discriminate between the 

multiple paper types used by each company. The results of this research show that the 

banknote company issues comprise a more extensive range of paper types than have been 

assumed by collectors over the past 100 years. Thickness frequency distribution data are 

shown to provide important clues about whether thickness variations are simply normal 

artifacts of manufacturing or whether they represent multiple paper types with different 

mean thicknesses. Results also provide insight to papermaking practices of the 1870s and 

1880s, with particular regard to composition, quality control of thickness, and the use of 

sizing to improve paper quality.

HISTORICAL BACKGROUND

Prior to 1894 all United States postage stamps were manufactured under contracts 

with private printing companies. Stamps manufactured between 1870 and 1889, the socalled “large banknote issues,” were produced by three corporations originally involved 

in printing currency and security paper: the National, Continental, and American Bank 

Note Companies. From 1870 through 1882, these companies printed more than 21.2 

billion stamps in twelve values, using papers that varied in both thickness and texture. 

Historical information about these papers is unavailable, as the government printing 

contracts provided no technical details on the materials to be used. No information has 

been found about the paper mills that supplied the printing contractors or about the 

products they provided.

The four printings of these issues are relatively easy to identify. Small design details 

differentiate National and Continental stamps as well as the two American printings 

(Figure 1). In late 1878, a so-called “soft” paper used by Continental is likely to have 

remained in use after Continental was acquired by American in February 1879. Proof of 

a Continental Bank Note Company origin of those stamps therefore depends on covers 

dated prior to American’s takeover.

John H. Barwis, Institute for Analytical Philately, 

P.O. Box 8035, Holland, Michigan, 49422-8035, 

USA. Correspondence: jbarwis@charter.net. Manuscript received 10 April 2013; accepted 26 April 

2013.
6 • smithsonian contributions to history and technology

Collectors have been aware of banknote issue paper variations for more than 100 years and have characterized them using 

a wide range of qualitative descriptions, as summarized in Table 

1. For most collectors it is sufficient to say the National and Continental papers tend to be thinner, stiffer, and more translucent 

than the thicker and softer American papers, and the sound from 

a “snap test” helps identify the two general groups. Controversies nevertheless remain among specialists:

• How many papers were used by these companies, and 

what characterizes them? 

• Did the National and Continental Bank Note Companies 

use the same paper?

• Is the paper used by Continental in late 1878 the same 

paper first used by American?

DATA COLLECTION

From an unsorted group of used, off-cover 3¢ greens, 

stamps were first allocated to their appropriate printing. Fifty of 

the most poorly centered stamps were chosen from each printing 

to ensure at least one wide margin for measuring thickness on 

noninked areas. Each stamp was numbered so that data collected 

could be linked to unique samples. The intent was to facilitate 

comparisons of parameters other than thickness, should distinct 

thickness-based subpopulations be established within a given 

printing.

Paper thicknesses were measured by the author. Fiber composition was determined by Robert Hisey, a professional paper 

engineer. Tests for sizing composition were conducted at Hope 

College’s Department of Chemistry. All other measurements and 

their analyses were done at the Center for Ink and Printability 

in the College of Engineering and Applied Sciences at Western 

Michigan University (Pekarovic et al., 2011; Pekarovicova et 

al., 2012).

Paper Thickness

The thickness of each stamp was determined by averaging 

three measurements of an ink-free margin. A Mitutoyo handheld micrometer with an anvil diameter of 0.25 inch (~6.4 mm) 

was used, which allowed each measurement to represent an 

area of at least 6 mm2

. This approach was preferred to caliperbased point measurements, which may overrepresent small-scale 

surface irregularities. The micrometer’s precision is 0.001 inch 

(0.0025 mm), and the digital display makes it easy to interpolate 

to the next decimal place.

The printed area of every stamp was also measured to 

test thickness of the ink layer. Results varied widely enough 

Figure 1. The four printings discussed in this paper. Shades vary widely, and most are not diagnostic as to printing. Stamp scans courtesy of 

Robert A. Siegel Auction Galleries, Inc.
number 57 • 7

(0.0002–0.0009 inch) to demonstrate that measurements of 

inked areas would not yield an accurate assessment of paper 

thickness.

Bending Resistance

The bending resistance of 50 stamps from each printing was 

measured by following the T543-om-00 standard of the Technical Association of the Pulp and Paper Industry (TAPPI), using a 

Gurley bending-resistance tester. This device measures the force, 

in Gurley units, required to bend a specimen by a given distance 

under controlled conditions. One Gurley unit is equivalent to the 

force exerted by gravity on 1 mg of mass.

Fiber Analyses

Fiber identification was done using TAPPI-recommended 

staining techniques (Isenberg, 1967:232, 271), and the results 

were photographed under transmitted light at ×100 magnification. Graff C stain allowed the differentiation of cotton/linen 

from woody fibers. Cochineal stain was used to distinguish 

cotton from linen. All samples were examined to evaluate fiber 

morphology.

Selected stamps from each printing were cut in half and immersed in cuvettes filled with 20 mL of sodium hydroxide (0.05N 

NaOH) and glass beads. Samples were shaken for 12 hours to 

repulp the paper for fiber analysis. Using a fiber quality analyzer 

(Op Test Equipment, Inc.), fibers were then analyzed for length 

and degree of deformation. 

Sizing Analyses

The presence and compositions of sizing used in the four 

printings were determined using the spot tests specified by the 

Foundation of the American Institute of Conservation (1990). 

Five samples were tested from each printing, with each group 

of five chosen to span the range of paper thicknesses observed 

in a respective printing. As the use of hazardous chemicals was 

required, all tests were performed under a laboratory hood by a 

trained chemist. Because some of the indicative stains produced 

Table 1. Principal paper types of the large banknote issues as seen by various observers.

Author

National BN Co.

1870 issue

Continental BN Co.

1873 issue

American BN Co.

1879 issue

American BN Co.

1881 issue

Luff (1902) White wove, thin to 

moderately thick

1. Stiff, hard, thin to thick

2. Semitransparent, almost 

pelure

3. Porous but thinner than 

type 4

4. Thick, soft, porous

Soft, porous, same as 1873 

type 4

Same as 1879

Wiley (1915) Hard, average thickness 

0.00275 inches

1. Hard, average thickness 

0.00275 inches

2. Soft “American” paper

Soft, average thickness

0.00330 inches

Soft, average thickness

0.00330 inches

Brookman (1966) 1. Hard, white, smooth 

surfaced, thin

2. A little thicker, slightly 

less hard than normal

1. Hard, same as National 

type 1

2. Soft “American” paper

1. Very soft, coarse mesh, 

more yellowish and 

not as smooth as hard 

papers

2. Intermediate paper, 

same stiffness as hard 

paper but more opaque

Very soft

Landau (1999, 2000) Thin, hard, white, starch 

sizing

Thin, hard, white, starch 

sizing

Unbleached newsprint, 

soft, straw to ivory color

Unbleached newsprint, 

 soft, straw to ivory 

color

Barwis (2001) n/a 1. Thin, hard, close wove

2. Thin, hard, open wove

3. Medium, soft, open wove

4. Thick, soft, open wove

n/a n/a

Scott Publishing Co. (2012) White wove, thin to 

medium thick

White wove, thin to thick Soft, porous Soft, porous
8 • smithsonian contributions to history and technology

were ephemeral, photographs of results were taken immediately 

after test completion.

Permeability

“Oil Gurley porosity” was measured at least five times for 

each stamp using a Technidyne Profile Plus instrument. Oil Gurley 

porosity represents the time in seconds necessary to pass 100 mL 

of air through a constant area of substrate. Although commonly 

designated “porosity” in the paper industry such measurements 

actually describe permeability. Porosity is a percentage of a given 

solid that is occupied by pore space. Permeability is the rate at 

which a fluid under a constant pressure will flow through a porous 

solid and represents the interconnectedness of pore space. Longer 

flow-through times indicate lower permeability, an effect of both 

fiber size and how densely fibers have been packed together to form 

the paper’s fabric. Highly permeable papers will absorb ink more 

readily and can lower the resolution of line-engraved printing.

Because the tested stamps were smaller than the instrument’s 

measuring aperture, two layers of polyethylene terephthalate 

(PET) sheet (100 × 80 mm) were taped together to create a folder 

through which a circular aperture of 9 mm was cut. The stamp 

was placed into the PET folder and measurements were taken 

through the perforated area of 63.6 mm2

. 

ANALYTICAL RESULTS

Most collectors approach the identification of the bank 

note company issues first by printing contractor, then by apparent differences in paper thickness when a stamp is held before a 

light source. Paper thickness data for each printer/contractor are 

therefore presented first. Other measurements are then related 

to these data.

Paper Thickness

Wiley (1915) was the first to determine thicknesses of 

banknote issue stamps and published measurements of the 3¢ 

greens produced under each printing contract. The measurements from this study confirm the ranges of Wiley’s data for each 

of the four printings and display the same trends within each 

printing. Table 2 combines new data with Wiley’s, with measurements given in ten-thousandths of an inch. 

Two general trends are evident in the raw data. First, the 

National Bank Note Company’s stamps comprise a slightly narrower thickness range than in any of the contracts from 1873 

onward. Second, each of the four printings can be characterized by more than one commonly occurring thickness. These are 

termed modal thicknesses. Note the relative underrepresentation 

of stamps 0.0031 inches thick (0.0787 mm) within the 1879 and 

1881 printings or 0.0029 inch-thick stamps (0.0737 mm) from 

the 1873 printing. 

Displaying these data graphically provides a better understanding of the relative frequency of occurrence of a given 

thickness. Figure 2 charts the percentages within each size class 

of the first two printings, as listed in Table 2. None of the resultant curves represents a single normal distribution, that is, 

a simple bell-shaped curve. Rather, each distribution displays 

more than one modal thickness. This suggests that under each of 

these contracts, papers were drawn from more than one population, a notion reflected by collectors’ observations (see Table 1). 

Whether these modes represent more than one paper source, or 

more than one production run from a single source, cannot be 

known from these data alone.

National paper thicknesses are bimodally distributed, with 

modes at 0.0025 and 0.0028 inches (0.0635 and 0.0711 mm, 

respectively). It is possible that these modes may represent the 

means of two overlapping normal distributions; more work 

needs to be done in this regard. Brookman (1966) observed two 

discrete papers types (see Table 1), which may well have been 

represented by these modes. Although Wiley’s (1915:7) data 

clearly reveal these modes, he obscured them by characterizing the paper with a single description and a mean thickness of 

0.00275 inches (0.0699 mm). Luff (1902) must have observed 

the thickness range and noted the existence of discrete subpopulations. Scott Publishing Co.’s (2012) descriptions do not recognize discrete paper types.

The frequency distribution of Continental paper thickness is 

striking in two respects. First, Continental stamps thinner than 

0.0030 inches (0.0762 mm) are characterized by the same modes 

as the National stamps. One is tempted to conclude that the two 

companies used the same two papers, perhaps obtained from the 

same supplier. However, stiffness, fiber length, and permeability 

data refute this; these characteristics will be discussed later. 

Second, a third mode at 0.0030 inches appears in the Continental distribution. This mode is also seen in the frequency 

distribution of 1879 American Bank Note Company stamps 

(Figure 3). This may be the paper Continental began using in the 

second half of 1878, which continued in use after American assumed control of Continental’s contract and printing operation 

on 4 February 1879 (Barwis, 2001). Here we have a problem: 

when off-cover stamps were sorted for this study, how could the 

“same” paper wind up in two different piles? The answer is that 

subtle variations do exist in paper translucence within a single 

thickness grade. Given a large group of stamps 0.0030 inches 

thick, an objective observer using translucence would call almost 

half of them Continentals. Another observer would likely produce a very different result. Thus, only covers dated before 4 

February 1879 can prove whether a stamp was printed by Continental (Scott Publishing Co., 2012). 

Most of American Bank Note Company’s stamps printed 

during the 1879 contract were on paper 0.0032–0.0034 inches 

thick. This modal thickness has a higher standard deviation than 

the modal thicknesses in earlier contracts and may suggest quality control issues at the paper mill. Modal thicknesses were narrower during the 1881 contract, in which the primary mode was 

the thinner (0.0030 inches) of these two papers.

What can we infer from the thickness data? In none of 

the four printings are paper thicknesses randomly distributed. 
number 57 • 9

Figure 2. Thickness frequency distributions for of the National 

and Continental Bank Note Companies’ 3¢ stamps, based on the 

data in Table 1.

Figure 3. Thickness frequency distributions of the American Bank 

Note Company’s 3¢ stamps.

Table 2. Thickness frequency distribution of 985 3¢ banknote stamps. Data from this study combined with Wiley (1915).

National, 1870 Continental, 1873 American, 1879 American, 1881

Thickness (inches) Number Percentage Number Percentage Number Percentage Number Percentage

.0019 – – 1 0.28 – – – –

.0020 1 0.67 1 0.28 – – – –

.0021 1 0.67 1 0.28 – – – –

.0022 1 0.67 7 1.94 – – – –

.0023 7 4.67 3 0.83 – – – –

.0024 9 6.00 17 4.72 – – – –

.0025 27 18.00 65 18.06 1 0.29 – –

.0026 19 12.67 41 11.39 2 0.57 5 4.00

.0027 24 16.00 61 16.94 2 0.57 5 4.00

.0028 28 18.67 70 19.44 14 4.00 6 4.80

.0029 18 12.0 22 6.11 8 2.29 4 3.20

.0030 7 4.67 43 11.94 56 16.00 37 29.60

.0031 4 2.67 9 2.50 17 4.86 8 6.40

.0032 3 2.00 13 3.61 57 16.29 21 16.80

.0033 1 0.67 4 1.11 53 15.14 10 8.00

.0034 – – 2 0.56 53 15.14 10 8.00

.0035 – – – – 40 11.43 6 4.80

.0036 – – – – 18 5.14 4 3.20

.0037 – – – – 13 3.71 3 2.40

.0038 – – – – 6 1.71 3 2.40

.0039 – – – – 4 1.14 2 1.60

.0040 – – – – 4 1.14 1 0.80

.0041 – – – – 2 0.57 – –

.0042 – – – – – – – –

Total 150 100.03 360 99.99 350 99.99 125 100.00
1 0 • smithsonian contributions to history and technology

Rather, they cluster around four thicknesses that may represent 

normal distributions around the means of four discrete populations. Some of the variation is no doubt due to the number of 

times stamps have been soaked by philatelists in the past 130+ 

years, as soaking tends to thicken and roughen paper. Soaking 

some stamps more often than others would tend to increase the 

standard deviation of a given population.

The thickness frequency data suggest the use of four modal 

thicknesses with different basis weights. Based on the weights 

of the 200 stamps used to collect the thickness data, the papers’ 

basis weights would have ranged from 53–56 g/m2

 (0.0025 

inches thick) to 69–72 g/m2

 (0.0032 inches thick).

Bending Resistance

Elastic modulus is the tendency of a solid to deform nonpermanently when a force is applied. It is basically the slope of the 

stress strain curve in the region of elastic deformation. Because 

bending resistance (stiffness) of a paper sample is a function of 

its thickness and its elastic modulus, elastic modulus can easily 

be determined, since

M = EI,

where M is bending moment or “stiffness” (bending force in 

Gurley units), I is moment of inertia (thickness squared times 

width), and E is elastic modulus.

Sample width can be neglected, since differences in stamp 

width were negligible. To determine the elastic modulus of a stamp, 

divide the measured bending force by the square of thickness:

E = M/T2,

where T is paper thickness.

The relationships between bending resistance and elastic 

modulus for each of the four printings are summarized in Figure 

4. The correlation coefficients, although not unduly low, may 

well have been reduced in part by the varying experience each 

piece of paper has had since its manufacture. Papers with identical thicknesses may have contained different percentages of fines 

in the pulp resulting from different treatment in the beater, thus 

widening the range of bending resistances. Sizing concentrations 

may have varied, which would also lead to greater variation in 

bending resistance. Variations in ink layer thickness would tend 

to broaden the range of bending resistances for any given paper 

thickness. Soaking stamps in water increased paper thickness 

and therefore decreased elastic modulus.

Table 3 shows that when National and Continental stamps 

were compared as entire populations, no significant difference 

was discerned in their elastic modulus. This is consistent with 

the “snap test” used by collectors for identifying “hard” versus 

“soft” paper. Although the mean elastic modulus of the 1881 

population is lower than the mean of the 1879 population, standard deviations indicate significant population overlap. 

Figure 4. Relationship between bending resistance and elastic modulus for the four printings. R

is the correlation coefficient.
number 57 • 1 1

A more revealing way to consider paper stiffness is to examine the differences in bending resistance within each printing, 

based on the modal thicknesses shown in Figures 2 and 3. Table 

4 lists the means and standard deviations of these moduli, which 

are depicted graphically in Figure 5. These data provide the first 

indication that identical thickness does not prove identical paper. 

For example, both of the modal thicknesses used by National 

were stiffer than paper of the same thickness used by Continental. The thinner of these two National papers is 13% stiffer than 

its Continental counterpart.

Elastic modulus data taken alone indicate no significant 

differences in 0.0030-inch-thick paper used in three of the four 

printings, although Continental’s displays a narrower standard 

deviation. This was most likely the paper on hand when the 

American Bank Note Company assumed control of Continental’s operation in February 1879. Paper supplied after depletion 

of the inherited supply may have been made to a less exacting standard. As we shall see later, sizing played a role in this 

regard.

In the third quarter of 1878 and January 1879 Continental 

delivered about 166 million 3¢ stamps to the Post Office Department (Luff, 1902). After February 1879, when American assumed Continental’s contract, more than 1.3 billion (6.5 million 

sheets) of these stamps were delivered prior to release of the 1881 

reengraved issue. Therefore, a random sample of Continental or 

American pre-reengraved stamps on 0.0030-inch paper is about 

eight times more likely to have been printed after January 1879.

The 0.0032-inch-thick paper used by the American Bank 

Note Company during the 1881 printing is considerably more 

pliable, that is, more easily bent, or flexible, than paper of the 

same thickness used in American’s previous contract. The 1881 

paper’s mean elastic modulus is about 16% lower, and variation about the mean is low (Figure 5). Other analytical results, 

particularly sizing and permeability, establish differences among 

papers that demonstrate very similar elastic moduli.

Fiber Analyses

The Graff C staining results are illustrated in Figure 6. Pale 

red to pink colors indicate cotton or linen. Pale blue indicates 

bleached cotton. Lignin (wood), which stains yellow, is absent 

except for a single fiber in the 1879 sample. The cochineal red 

staining results are shown in Figure 7. Cotton fibers are stained 

red; notice the absence of fibers other than cotton. In none of the 

samples was any evidence seen that would support the presence of 

soda/sulfite pulp in the American Bank Note Company printings, 

as reported by White (1983:64–65). Occasional stray fragments 

that stained as lignin are likely to have been detritus inadvertently 

introduced in the manufacturing process. A few fragments of unidentifiable debris were also observed but are immaterial.

A total of 23 stamps was repulped for fiber size analysis. 

Although this is an insufficient number to quantify differences 

among paper types, the data can establish variations between the 

fabrics of papers with identical composition and thickness. Mean 

fiber lengths range from 0.532 to 0.732 mm and are shortest in 

Table 3. Elastic modulus data for 1870–1881 U.S. 3¢ stamps 

without regard to thickness differences within each printing.

 Elastic modulus mean/

Printing Stamps standard deviation

National, 1870 50 .53/.09

Continental, 1873 50 .51/.14

American, 1879 50 .42/.08

American, 1881 50 .36/.08

Table 4. Elastic modulus data for all stamps that match the 

four modal thicknesses shown in Figures 2 and 3.

 Elastic modulus mean/standard deviation

.0025 .0028 .0030 .0032

Printing inches inches inches inches

National, 1870 .61/.08 .54/.09 – –

Continental, 1873 .53/.14 .47/.12 .40/.06 –

American, 1879 – – .43/.10 .43/.11

American, 1881 – – .40/.11 .37/.05

Figure 5. Elastic moduli of the four modal thicknesses shown 

in Figure 3. Red squares are means; blue squares are the standard 

deviation.
1 2 • smithsonian contributions to history and technology

Figure 6. Graff C stain for the presence of wood. Pink and pale red indicate cotton or linen. Pale 

blue is bleached cotton. Yellow fiber (red arrow) may be softwood. Staining and photomicrography 

courtesy of Robert Hisey.

Figure 7. Cochineal red stain for distinguishing cotton from linen. Red indicates cotton; violet indicates linen. Staining and photomicrography courtesy of Robert Hisey.
number 57 • 1 3

the Continental papers (Figure 8). Shorter fibers suggest longer 

or more intense beating of the cotton rags used as feedstock for 

pulp making. This is supported by the observation that cotton 

fibers in the Continental papers are the most deformed of the 

four printings (Pekarovic et al., 2011). A fiber size frequency distribution skewed toward the fine fraction may have adversely 

impacted permeability. Additional work would be required to 

support this conclusion.

Sizing Analyses

Sizing increases a paper’s surface strength and stiffness and 

may provide a smoother finish. Sizing also imparts some form 

of liquid resistance to the paper or paper fibers by increasing the 

surface energy or decreasing the porosity of the paper. Sizing that 

increases surface energy forms a water-repellent film on paper fibers, which inhibits adsorption of water but not oils. This allows 

a higher proportion of ink to remain on the printed surface and 

minimizes ink feathering. Rosin/alum was used for this purpose. 

Because it was added to pulp slurry, usually in the machine chest 

or the headbox, it is considered “internal sizing,” called “beater 

sizing” in the nineteenth century. 

Surface sizing involves immersing dried paper into a sizing 

solution, an extra step that adds production time and therefore 

increases unit cost. These sizing types, which include starch and 

gelatin, form films that decrease paper porosity and permeability. 

Five stamps from each of the four printings were laboratory tested for the presence of the three principal sizings used 

in nineteenth century paper manufacturing: gelatin, rosin/alum, 

and starch. Standard spot tests were used for these analyses, as 

summarized in Table 5.

Gelatin was used as sizing in all of the National and Continental stamps tested. Figure 9 illustrates the typical results. Note 

that both of the American Bank Note Company printings tested 

negative for gelatin but responded differently to the hydroxyproline test: yellow-brown results for 1879 stamps and pale straw 

to colorless for 1881 stamps. Although the hydroxyproline test 

was not designed to indicate sizing other than gelatin, the fact 

that the two American Bank Note Company printings responded 

differently suggests the papers have different chemical compositions. It turns out this is the case, as only the American Bank 

Note Company’s 1879 printing tested positive for rosin. Figure 

10 shows the characteristic pink to raspberry stain indicating 

Figure 8. Fiber lengths determined from selected repulped stamps. 

Length data from Pekarovic et al. (2011).

Table 5. Stains used to identify paper sizing.

Sizing Type Spot test Result

Gelatin Internal Hydroxyproline Rose red or pink shades 

indicate gelatin

Starch External Iodine potassium Deep blue to black 

 iodide shades indicate starch

Rosin External Raspail #1 Pink to raspberry shades 

indicate rosin

Figure 9. Hydroxyproline test for the presence of gelatin. Rose red 

to pink liquids indicate gelatin sizing. Colorless to brown indicates 

absence of gelatin. Tests courtesy of Eric Greve, Hope College Department of Chemistry
1 4 • smithsonian contributions to history and technology

rosin, which appears for only 5–10 seconds, after the stain solution is wiped off. 

Rosin is never used alone as sizing because it will not adhere to paper fibers but is always used in combination with a 

mordant, usually alum. Alum is slightly acidic (pH 4.5–7.9), so 

over time rosin/alum-sized papers can become discolored. Its inclusion in the American Bank Note Company’s 1879 printing is 

probably the reason that these stamps are usually seen with yellower paper than any of the other three printings.

For its 1881 printing the American Bank Note Company 

switched to paper sized with starch. Figure 11 illustrates the results of the positive spot test, a bluish-black stain. The 1881 issue 

papers are whiter than the 1879 papers because only starch was 

used as a sizing. 

Figure 11. Iodine potassium iodide spot test for starch, indicated by a bluish-black stain. Only 

the 1881 issue tests positive. Test courtesy of Eric Greve, Hope College Department of Chemistry.

Figure 10. Raspail #1 test showing pink to raspberry color halo around the central spot where the stain was applied, a positive indication for 

rosin. Brown toning of the paper is due to the saturated sulfuric acid used in the stain. Test courtesy of Eric Greve, Hope College Department 

of Chemistry.
number 57 • 1 5

Why were three different sizings used for the paper to print 

these issues? The decision to purchase rosin/alum-sized paper 

in 1879 was undoubtedly an economic decision by the American Bank Note Company, since the change would have lowered 

their unit cost of paper. When the mill introduced rosin/alum 

into the slurry, the process of drying the paper and then rewetting it in a sizing tank was eliminated. This would have speeded 

production, simplified equipment maintenance, and decreased 

unit labor cost, thus allowing the manufacturer to sell at a more 

competitive cost. 

Permeability

When all four printings are considered as a single population, no discernible relationship exists between permeability 

and paper thickness (Figure 12). The reasons for this are fairly 

straightforward. At least five factors influenced the permeability 

of these stamps.

1. For a given thickness, paper varies in closeness of weave 

and degree of calendering.

2. For a given thickness, paper varies in the degree of calendering, a process of smoothing by passing through 

rollers.

3. The composition and concentration of sizings varies considerably.

4. Ink layer thickness varies by a factor of four.

5. Stamps were exposed to a wide range of postuse treatment (soaking history).

A more incisive way to examine these data is to consider 

permeability variation between the modal thickness groups (see 

Figures 2 and 3) of each printing. The mean values of elastic 

modulus for each modal thickness group are plotted against each 

group’s mean permeability in Figure 13. Stiffer paper is toward 

the right of this chart, and less permeable paper is toward the 

top. From 1870 to 1879, the trend was toward papers that were 

less pliable and less permeable. Then in 1881 the American Bank 

Note Company changed to a more pliable and more permeable 

paper. It was a less acidic paper than the company had previously 

used, which is why today the 1881 papers are generally whiter 

than the 1879 papers. Figure 14, which overlays the chart in 

Figure 13 with the type of sizing used, paints a clearer picture of 

the varieties of paper involved. 

Figure 14 shows gelatin-sized papers span a wide range of 

stiffness and permeability. The stiffest gelatin-sized paper is also 

one of the thinnest—the 0.0025-inch-thick paper used by the National Bank Note Company. The thicker of the two National papers and Continental’s 0.0025-inch-thick paper have very similar 

stiffness and permeability. The thickest Continental paper—the 

0.0030-inch-thick paper used in late 1878 and January 1879—is 

the most pliable paper used by that company and is the least permeable of all papers used for the 3¢ stamps. Continental’s 1878 

gelatin-sized paper is very close to the rosin/alum-sized papers in 

both permeability and stiffness.

Although permeabilities of American’s 1881 starch-sized 

papers are close to the permeabilities of two gelatin-sized papers, 

the starch-sized papers are far more pliant.

Paper’s Impact on Print Quality

All three printing companies constantly dealt with the 

same challenge facing all manufacturers in managing the tension between minimizing unit production cost while retaining or 

improving product quality. Intaglio printing required paper pliable enough to be forced into printing plate recesses but strong 

enough to withstand the printing process and to yield prints not 

easily prone to wrinkling or tearing. Too much pressure applied 

in the calendering process might result in stronger paper but 

weaker resolution of fine line engraving. Less sizing might result 

in pliability more suitable for gravure printing, but unsized or ineffectively sized paper might cause blurry images from ink bleed.

This study suggests that type of sizing, rather than paper 

thickness or permeability, was the greatest influence on print 

quality. Figure 15 shows examples of stamps from each of the 

regions on the chart in Figure 14. First, considering groups of 

stamps with similar elastic moduli, compare line resolution of 

either of the two starch-sized stamps with either of the rosin/

alum- or gelatin-sized stamps. The 1881 reengraved stamps 

tend to look flat, in some instances resembling offset prints. 

One could reasonably hypothesize that permeability of the reengraved stamps—which is more than double that of the rosin/

alum-sized stamps or the Continental 0.0030-inch-thick, gelatinsized stamps—caused ink to be imbibed by the paper. Indeed, the 

ink layer is on average slightly thinner on the reengraved stamps. 

But the entire range in ink layer thicknesses for 200 stamps is 

only 0.0004 inches, and the range of average ink layer thicknesses varies between printings by only 0.00004 inches. 

Figure 12. Permeability versus paper thickness of the 1870, 1873, 

and 1879 issues.
1 6 • smithsonian contributions to history and technology

Figure 13. Mean elastic modulus versus mean permeability for each of the four modal thicknesses of paper. Note that permeability increases downward on the vertical axis. Paper stiffness 

increases toward the right on the horizontal axis.

Figure 14. Mean elastic modulus versus mean permeability for each of the four thickness groups. 

Shaded areas enclose papers with the same sizing.
number 57 • 1 7

A better way to understand the relative importance of permeability versus sizing is to compare groups of stamps with 

similar permeability. Compare images of starch-sized stamps 

in Figure 15 to those from all three modal thicknesses in the 

lower end of the field of gelatin-sized stamps in Figure 14. The 

0.0025-inch-thick paper used by the National Bank Note Company is the most permeable of all the paper types, yet the images 

on this paper are usually crisp. Weak lines are sometimes seen, 

but those cases are seldom blurry and are probably just the result of overly aggressive plate wiping. Nor does paper thickness 

appear to play much of a role in image quality. Continental’s 

images on 0.0030-inch-thick paper are just as finely resolved as 

those throughout the entire thickness range.

SUMMARY AND CONCLUSIONS

The main types of banknote issue papers traditionally have 

been defined on the basis of thickness and relative stiffness. This 

has always been a sensible approach for collectors. After all, 

what collector wants to run a lab test on a stamp (especially a 

destructive one) before adding it to his or her album? Yet to understand how banknote stamps were produced and the reasons 

behind their appearance requires a closer look. Paper that looks 

the same may perform very differently as an image platform.

The question “How many paper types are there?” can be 

answered quickly only if the basis for “type” is specified. If 

one is interested in paper thickness, there are four paper types, 

Figure 15. The influence of sizing on print quality.
1 8 • smithsonian contributions to history and technology

each with a fairly wide range about a mean thickness. If one 

is concerned primarily with the printing surface as influenced 

by sizing, there are three types. Table 6 summarizes the paper 

characteristics of the main types of paper used to print the large 

banknote issues. 

Within each of the 1879 and 1881 issues, the two main 

modal thicknesses display no significant differences in elastic 

modus or permeability. Print quality differences are due to different sizings. 

The National and Continental Bank Note Companies did 

not use the same papers. Although both companies used .0025-

and .0028-inch-thick gelatin-sized paper, the elastic moduli and 

permeability of both papers vary significantly between printings. 

In fact, the thicker of the two National papers is most similar to 

the thinnest Continental paper.

Continental’s thickest paper, the so-called “transitional 

paper” used in late 1878, was no doubt used by the American 

Bank Note Company in early 1879 until the supply was depleted. 

However, this .0030-inch-thick paper was made with different sizing than most paper of the same thickness also used by American.

At no time in either of the American Bank Note Company’s two printings was newsprint—cheap paper made from 

“groundwood”—used for postage stamp production. Groundwood is made by pushing logs against a grindstone, whereas the 

American papers are cotton. The few wood fragment seen in the 

Continental and American papers are most likely just debris that 

found its way into the pulp. 

ACKNOWLEDGMENTS

James E. Allen provided all stamps used in the analyses, as 

well as insights into sizing chemistry. Measurements done at the 

Center for Ink and Printability at Western Michigan University 

were supported by a 2011 research grant from the Institute for 

Analytical Philately, Inc. I thank Alexandra Pekarovicova for her 

helpful involvement in this work. I am grateful for the help of 

Paper Engineer Robert Hisey, who analyzed fiber composition 

and offered valuable advice on paper manufacturing techniques. 

I also thank Graham Peaslee, and his student Eric Greve, of the 

Department of Chemistry at Hope College, for performing the 

sizing spot tests. Technical reviews of this paper by James Allen, 

David Herendeen, and Robert Hisey are greatly appreciated.

REFERENCES

Barwis, J. H. 2001. “United States Three-Cent Continental: Date Ranges of Varieties.” In Sixty-Seventh American Philatelic Congress, pp. 1–19. Chicago: 

American Philatelic Congress.

Brookman, L. G. 1966. The United Sates Postage Stamps of the 19th Century. 

Volume 2. New York: H. L. Lindquist.

Foundation of the American Institute of Conservation. 1990. Conservation OnLine, Spot Tests for Sizing. http://www.cool.conservation-us.org/coolaic/sg/

bpg/pcc/10_spot-tests.pdf (accessed 15 January 2013).

Isenberg, I. H. 1967. Pulp and Paper Microscopy. 3rd ed. Appleton, Wis.: Institute 

of Paper Chemistry.

Landau, E. A. 1999. “Identifying the Large Bank Note Stamps.” In Linn’s U.S. 

Stamp Facts, 19th Century, pp. 251–257. Sydney, Ohio: Amos Press.

———. 2000. Continental vs. American Papers: The EKU of King Scott’s New 

Clothes. Chronicle, 52(4):280–283.

Luff, J. N. 1902. The Postage Stamps of the United States. New York: Scott Stamp 

and Coin.

Pekarovic, M. A., A. Pekarovicova, J. Pekarovic, and J. Barwis. 2011. Papermaking, Ink Chemistry and Printability of the United States Three-Cent Bank 

Note. Paper presented at the 63rd Annual Technical Conference of the Technical Association of the Graphic Arts, Pittsburgh, Pa. Available at http://

www.printing.org/abstract/10661 (accessed 15 January 2013).

Pekarovicova, A., M. Simekova, J. Pekarovic, and J. Barwis. 2012. Metals in Paper 

and Ink of United States Three-Cent Bank Note. Paper presented at the 64th 

Annual Technical Conference of the Technical Association of the Graphic 

Arts, Jacksonville, Fla. Available at http://www.printing.org/abstract/10997

(accessed 15 January 2013).

Scott Publishing Co. 2012. 2012 Specialized Catalogue of United States Stamps. 

Sydney, Ohio: Scott Publishing.

Wiley, H. L. 1915. The U.S. 3c Green 1870–1887. Boston, Mass.: Mekeel-SevernWiley.

White, R. H. 1983. The Papers and Gums of United States Postage Stamps. 

Germantown, Md.: Philatelic Research.

Table 6. Summary of paper characteristics of the main types of paper used to print the large banknote issues.

Thickness Average elastic Average permeability 

Type Issue Printer (inches) Sizing modulus (s/100 mL)

1 1870 National .0025 Gelatin .61 26.7

2 1870 National .0028 Gelatin .53 37.8

3 1873 Continental .0025 Gelatin .54 38.1

4 1873 Continental .0028 Gelatin .47 62.9

5 1873 Continental .0030 Gelatin .40 75.8

6 1879 American .0030 Rosin/alum .43 69.0

7 1879 American .0032 Rosin/alum .43 73.7

8 1881 American .0030 Starch .40 36.4

9 1881 American .0032 Starch .37 33.6
A Scientific Analysis of the First Issues of Chile 

1853–1862, London Printing

Thomas Lera, Jennifer Giaccai, and Nicole Little

ABSTRACT. The London printings of the Chilean postage stamps between 1853 and 

1862 were examined using analytical instruments available at the Smithsonian Institution. There are four broad major technical areas important to philatelic research: color 

science (colorimetry and luminescence), paper chemistry (composition, thickness, and 

roughness), ink chemistry (pigment and binder composition), and printing methods (engraving and lithography). The analyses performed in this study address these four broad 

major technical areas while providing an understanding of the characteristics of these 

stamps, showing the utility and capability of forensic and scientific equipment available to philatelic researchers and offering an effective, rapid, and nondestructive way 

of identifying the pigments and dyes in the inks and papers used. X-ray fluorescence 

(XRF), Fourier transform infrared spectroscopy (FTIR), colorimetry, and X-ray diffraction (XRD) were all used on the stamps without damaging the samples. In some cases 

different XRF and FTIR manufacturers were used to compare the capabilities of different instruments in analytical philately. Because of the significant sensitivity differences 

of the equipment, the results are often complementary. Only by combining the results 

from several pieces of equipment was it possible to gather enough information to fully 

differentiate between the stamps and to obtain the complete characterization for each 

ink, pigment, and paper. This paper gives guidance as to which scientific instruments and 

methods are most useful when examining different characteristics of stamps. The results 

show the inks vary considerably between different printings. In the various red inks used 

by Perkins, Bacon & Co. the variation in the amounts of iron, calcium, and potassium 

used in the stamps examined show printer experimentation in the recipe used to make 

the ink. However, comparison between two blue inks used between 1853 and 1862 show 

little variation in the components used. This suggests much of the variation in the red ink 

recipe is due to Perkins, Bacon & Co. trying to solve the bluing problem present in many 

of their stamps during this time period.

INTRODUCTION

Using different pieces of scientific/forensic equipment at the Smithsonian National 

Postal Museum (NPM) and Smithsonian Museum Conservation Institute (MCI), this 

study focuses on the London printings of the Chilean postage stamps issued between 

1853 and 1862. 

Thomas Lera, National Postal Museum, Smithsonian Institution, P.O. Box 37012, MRC 570, 

Washington, D.C., 20013-7012, USA. Jennifer 

Giaccai and Nicole Little, Museum Conservation 

Institute, Smithsonian Institution, 4210 Silver Hill 

Road, Suitland, Maryland, 20746, USA. Correspondence: lerat@si.edu. Manuscript received 10 

April 2013; accepted 26 April 2013.
2 0 • smithsonian contributions to history and technology

STAMPS AND PAPER

A listing of the Chilean stamps is given below (Scott Publishing Co., 1997).1

• First London Printing, July 1853 

 5 centavos brown-red on blued paper (Chile number 

1)—issued 300,000 stamps

 10 centavos deep bright blue on yellowish-white 

paper (Chile number 2)—issued 200,160 stamps

• Second London Printing, May 1855 

 5 centavos brown-red on blued paper (Chile number 

8)—issued 2,040,000 stamps

• Third London Printing, October 1861 

 10 centavos bright blue on yellowish-white or lightly 

blued paper (Chile number 12)—issued 3,000,000 

stamps 

• Third London Printing, 1 January 1862 

 1 centavo lemon yellow on yellowish-white paper 

(Chile number 11)—issued 3,000,000 stamps

 20 centavos green on yellowish-white paper (Chile 

number 13)—issued 3,000,000 stamps.

Four major technical areas are important to philatelic research of the Chile stamps: color science (colorimetry and luminescence), paper chemistry (composition, sizing, thickness, and 

roughness), ink and gum chemistry (pigment and binder composition), and printing methods (engraving and lithography). The 

analyses performed in this study address these four major areas 

while providing an understanding of the characteristics of these 

stamps, showing the utility and capability of forensic and scientific equipment available to philatelic researchers and offering an 

effective, rapid, and nondestructive way of identifying the pigments and dyes in the inks and papers used.

X-ray fluorescence (XRF), Fourier transform infrared spectroscopy (FTIR), colorimetry, and X-ray diffraction (XRD) were 

all used on the stamps without damaging the samples. In some 

cases (XRF and FTIR) multiple instruments used the same analytical technique to further explore the capabilities of different 

instruments in analytical philately and of the significant sensitivity differences of the equipment, and the results are often 

complementary. Only by combining the results from several 

pieces of equipment was it possible to gather enough information to obtain the complete characterization for each ink, pigment, and paper. This paper gives guidance as to which scientific 

instruments and methods are most useful when examining different characteristics of stamps.

HISTORY

On 14 June 1852, Messrs. Lyon Brothers, agents for the 

Chilean government, sent a letter from Valparaiso to Perkins, 

Bacon & Co. on behalf of the Chilean government. The letter 

contained an order for postage labels (stamps): 300,000 five 

centavos printed in red vegetable ink and 200,000 ten centavos 

printed in blue vegetable ink, as well as the original steel printing 

plates, 100 reams of watermarked paper, one gross obliterating 

hand stamps, and one dozen bottles of obliterating ink (Bacon, 

1902; De Worms, 1953; Gálvez, 1964; Blank, 1989; Chile the 

“Colon” Issues, 2011; Granzow, 2012).

On 31 January 1854, a second printing was ordered for 

an additional 2,040,000 five-centavos postage labels printed in 

red vegetable ink, 100 pounds of gum, the printing plate, and a 

printing press with complete instructions on how to apply the 

ink and use the press (De Worms, 1953).

The third and final order was received by Perkins, Bacon 

& Co. on 8 December 1859 for 3,000,000 postage labels of 1 

centavo printed in yellow vegetable ink, 10 centavos in blue vegetable ink, and 20 centavos in green vegetable ink. The four different value stamps printed by Perkins, Bacon & Co. are shown 

in Figure 1.

Included in the shipment to Valparaiso were the steel printing plates, reams of watermarked paper, 56 pounds of red vegetable ink, 30 pounds of blue vegetable ink, 25 pounds each of 

green and yellow vegetable inks, and 250 brass canceling devices 

with the word “CANCELLED” located between four straight 

lines (De Worms, 1953). Although the printed stamps and supplies left London in September 1860, the 10-centavo stamp was 

issued for postal use in October 1861, and the 1-centavo and 

20-centavo stamps were issued on 1 January 1862. 

Figure 1. Chile first issues—the London printings (left to right: Scott numbers 1, 2, 8, 11, 12, and 13).
number 57 • 2 1

Perkins, Bacon & Co. inks were typically composed of 

two parts, a liquid and a dry pigment. The liquid portion was 

referred to as “oil,” as it was made by heating linseed oil and 

beeswax until slightly burned. This provided a carrier or varnish 

for the pigment. To this mixture “soft soap,” which helped to 

disperse the pigment and turpentine, was added to thin the oil 

to the desired viscosity. One or more dry pigments or colorants 

were mixed into the oil to form the final ink (Bacon, 1920b:181).

Many of the Perkins-Bacon inks were cyanide based. Six 

colorants can be made by the reaction of iron with the carbonnitrogen radical (–C ≡ N), cyanide: Prussian yellow, Prussian red, 

Prussian blue, Chinese blue, Prussian green, and Prussian brown 

(Granzow, 2012).

MICROMETER

A micrometer can calculate the exact thickness of a sheet of 

paper or a printed stamp. The paper used for the Chile stamps 

was handmade; due to the human element, one sheet of handmade 

paper differed from the next in thickness. Such variation in thickness is expected because, in the 1840s in Great Britain, paper was 

sold by weight per ream. “The supplies of the watermarked paper 

furnished to Perkins, Bacon & Co. under Mr. Stacey Wise’s contract, were made in triple sheets (311⁄2 by 591⁄4 inches), and every 

sheet was divided into three parts before it was used for printing 

the stamps. The three divisions of the sheet when cut each measured 10 1⁄2 by 19 3⁄4 inches. The weight per triple ream was 311⁄2 

lbs, one ream equaling 500 sheets” (Bacon, 1920a:40–43).

COLORIMETRY

The use of colorimetry in philately has been discussed in 

depth in a recent article by Herendeen et al. (2011) and Allen 

and Lera (this volume).

X-­Ray Fluorescence

Nondestructive X-ray fluorescence (XRF) analysis is one of 

the most widely used and versatile of all instrumental analytical 

techniques. An XRF spectrometer uses primary radiation from an 

X-ray tube to excite secondary X-ray emission, or fluorescence, 

from a sample. The energy (in kV) of the fluoresced radiation is 

used to identify the chemical element from the sample that emitted 

the X-ray. For a very X-ray dense material, for example, a metallic 

alloy, the XRF spectrum penetrates only a few micrometers into 

the sample. For stamps, however, it should be expected the XRF 

spectrum will include elements from all the layers of the stamp: 

ink, cancellation, paper, gum, and any residual backing material. 

The height and area of each X-ray peak, measured in counts, relates to the concentration of the element in the sample. For further background on X-ray fluorescence see reviews by Hahn et al. 

(2006) and Janssens et al. (2000). XRF has been used on stamps 

before, both alone and in conjunction with other techniques, to 

study the materials used in the manufacturing of the stamps as well 

as to identify counterfeits (Sanchez and Valentinuzzi, 2006; Castro 

et al., 2008; Cesareo and Brunetti, 2008; Preiss and Robie, 1982). 

Infrared Spectroscopy

Fourier transform infrared (FTIR) spectroscopy refers to the 

manner in which the data are collected and converted from an 

interference pattern to an infrared spectrum and is used for the 

identification of organic as well as inorganic materials. By interpreting the infrared absorption spectrum, the chemical bonds in 

a molecule can be determined. For most common materials, the 

spectrum of an unknown can be identified by comparison to a 

library of known compounds (Griffiths and de Haseth, 2007; 

Infrared and Raman Users Group, 2013). 

A common method of acquiring IR spectra is using attenuated total reflection FTIR (ATR-FTIR). When using ATR-FTIR, 

the sample must be in complete contact with the ATR window, 

which frequently involves applying pressure to the sample. The 

infrared light in ATR-FTIR penetrates a small amount into the 

sample; the depth of penetration in ATR-FTIR is greater than 

the thickness of the ink, so information on both the paper and 

ink will be present in an ATR-FTIR spectrum. ATR-FTIR produces slightly different spectra when compared to the standard 

transmission spectra in an infrared library. ATR spectra can be 

easily corrected, if desired, before comparing to an IR library. 

Because of the small size of postage stamps, ATR-FTIR can generally be used without requiring a sample to be extracted from 

the stamp or any modification of the instrument. For more background on infrared spectroscopy see Derrick et al. (1999). Infrared spectroscopy has been used previously to examine the ink 

used in stamps; however, most of the data came from ink samples 

removed from the stamps (Ferrer and Vila, 2006).

X-­Ray Diffraction

Powder X-ray diffraction (XRD) is perhaps the most widely 

used X-ray diffraction technique for characterizing materials and 

examining the crystalline structure of compounds. Although this 

technique is typically thought of as useful for inorganic materials, some organic materials are also quite crystalline and can 

give identifiable X-ray diffraction data. As with infrared spectroscopy, X-ray diffraction data are generally compared to a library of known reference materials to identify the compounds 

that produced the peaks.2

MATERIALS AND METHODS

Stamp Selection

Because of security issues with moving the Bernard Peyton 

Collection of Chile (accession number 223486)3 out of the NPM, 
2 2 • smithsonian contributions to history and technology

analysis of the author’s private collection was performed using 

forensic equipment at MCI. 

Video Spectral Comparator 6000

Optical examination was completed using the NPM’s Video 

Spectral Comparator 6000 (VSC 6000) manufactured by Foster 

+ Freeman, Ltd. in Evesham, Worchestershire, United Kingdom 

(Figure 2). The VSC 6000 allows examination of the stamps 

using incident and transmitted visible and near-infrared illumination between 400 and 1000 nm. 

Twenty Chile stamps of each issue were tested. Each stamp 

was placed in the VSC 6000 and enlarged using a magnification 

factor of 8 so the sensor area (represented by crosshairs) was 

able to average the color over a 0.2 mm2 area (Figure 3). Three 

inked points were sampled on each stamp. If the stamp was canceled, an attempt was made to sample “pure” color, that is, a 

region with no apparent white or black.

For each of the three points, the spectral reflectance curves 

were plotted to verify the readings, yielding consistent results. 

During the data collection procedure, a visual inspection of each 

graph was made to insure no highly inconsistent measurements 

were obtained. In the event inconsistent data were recorded, one 

or more of the data points for the sample would be retested. 

These data points were averaged and used in the following 

analysis.

For each of the samples, a full range of colorimetry data 

was collected and reviewed, including chromaticity diagrams 

(both CIE 1931 and CIE UCS 1960). All tabular data, including tristimulus values, CIE 1931 x,y coordinates, CIE UCS 1960 

u,v coordinates, and CIE UCS 1976 L*u*v* coordinates, were 

collected.

At the time of the analysis, the VSC 6000 did not support 

CIE 1976 u′,v′ chromaticity coordinates. The measured tristimulus values (X, Y, Z) were used to compute these coordinates 

using the standard transformations (Herendeen et al., 2011; 

Herendeen, 2011): 

u . X Y

X v X Y

Y

15 32

4

15 32

9 = + + = + + l l

On 14 November 2012, the software program was updated 

to version 160 to calculate these values.

OTHER COLORIMETRIC ANALYSIS

Concurrently with the colorimetric analysis, James Allen, a 

recognized philatelic color expert, categorized all of the stamps 

in a controlled environment illuminated with a 5000 K daylight 

source. Stamps were held at a constant angle of inclination with 

respect to the light source. 

Paper Thickness

The Testing Machines Inc. model 49-76-01, a precision 

micrometer suitable for measuring thin sheet materials—paper, 

tissue paper, and cardboard (Figure 4)—at the NPM, was used 

to measure the thickness of the stamp. The measuring range of 

the micrometer is 0.000–1.250 mm with a resolution of 0.1 μm 

and an anvil diameter of 1.59 cm (0.68 inches) with a contact pressure of 7.3 psi. It conforms to Technical Association of 

the Pulp and Paper Industry (TAPPI) T-411 standards. The micrometer has a large digital display, auto zero, motorized auto 

cycling, and a serial port for data communications to graph 

master software with the results exported to a Microsoft Excel 

spreadsheet. 

Microscopy

The Leica microscope model M205C, with magnification 

range from ×78 to ×1,600, was used in conjunction with the VSC 

6000 software to record close examination details (Figure 5).

Figure 2. Video Spectral Comparator 6000 (VSC 6000). 

Figure 3. Sampling point on Chile number 12.
number 57 • 2 3

X-­Ray Fluorescence

Two instruments were used for XRF of stamps in this project. At the NPM, a Bruker handheld Tracer III-SD X-ray fluorescence analyzer uses a rhodium X-ray tube with a silicon drift 

detector that has a resolution of 145 kV (Figure 6) and a spot 

size of ~0.5 cm2. Spectra were acquired at a voltage of 40 kV, 

beam current of 6 μA, and live time of 180 seconds. The depth of 

penetration was 4.61 cm (1.8 inches), passing through the entire 

stamp. Results were obtained by integrating the area under each 

peak and were grouped and averaged by issue. Twenty Chile 

Figure 4. Testing Machines Inc. model 49-76-01 micrometer.

Figure 5. (top) Leica microscope and (bottom) Chile number 1 at 

×100 showing some bluing of the paper.

Figure 6. Bruker Tracer III-SD X-Ray Fluorescence Analyzer.
2 4 • smithsonian contributions to history and technology

number 1 stamps were averaged, as well as ten stamps for each 

of the other five London printings. 

At MCI, a Bruker Artax X-ray fluorescence spectrometer 

with a rhodium X-ray tube, an 80 μm polycapillary lens, and a 

silicon drift detector (Figure 7) were used. Maps were acquired 

over the denomination indicator in the lower left corner at a 

resolution of 0.1 mm. Each spot was analyzed at 40 kV, 200 μA 

under helium atmosphere for a live time of 20 seconds. Using 

the Artax 7.2.5 software, all the spectra obtained in a map were 

summed, elements of interest were identified, and the concentrations for those elements were mapped. By looking at the maps 

produced for each element, it could quickly be observed whether 

an element was primarily in the ink, paper, or any cancellation or 

was a contaminant in the stamp. 

Fourier Transform Infrared Spectroscopy

Infrared analysis at the NPM was undertaken with the 

Bruker ALPHA FTIR Spectrometer (Figure 8) with a diamond 

ATR sampling module. The spectrometer uses a deuterated triglycine sulfate (DTGS) detector. The data are collected over a 

spectral range of 4,000–650 cm–1 at 4 cm–1 spectral resolution 

for 24 scans. The depth of penetration varies with wavelength 

and for different materials; however, using a diamond ATR window, it can be estimated that the depth of penetration is approximately 2 μm.

Additional infrared spectroscopy was acquired at MCI 

using a diamond ATR GoldenGate accessory in a Thermo Nicolet 670 bench with a DTGS detector. Spectra were acquired at 

a resolution of 4 cm–1 for 64 scans. The recent acquisition of a 

diamond ATR objective for the Thermo Nicolet Continuum infrared microscope allowed microscopic infrared analysis of some 

stamps, and spectra were collected using this MCT/A detector 

between 4,000 and 650 cm–1 at a resolution of 4 cm–1 for 128 

scans. (Figure 9).

X-­Ray Powder Diffraction

The Rigaku D/Max Rapid (Figure 10) at MCI collimates 

monochromatic X-rays to a microbeam, which can be focused on 

samples as small as 100 micrometers in diameter. The instrument 

Figure 7. Bruker Artax XRF spectrometer.

Figure 8. Bruker FTIR Alpha.
number 57 • 2 5

moves the sample through an arc during X-ray exposure in order 

to randomize orientation of the crystallites with respect to the 

beam as much as possible. In this way, the characteristic angles 

of diffraction appear as whole or partial Debye cones. Patterns 

were collected using a copper X-ray tube using the Ka line. The 

stamps were mounted on the holder using wax, with care taken 

to align the XRD sample spot so that the wax and aluminum 

holders were not in the area to be analyzed. Data were collected 

for five minutes using the 0.8 mm collimator while the goniometer was fixed at 0° (Φ) and 20° (Ω).

The XRD patterns produced, after background subtraction, 

were qualitatively matched using Jade 8.0 software to reference patterns of known materials in the International Center for 

Diffraction Data libraries and/or user libraries developed from 

reference materials. The depth of penetration into a sample is 

typically on the order of 20–100 μm, depending on the density 

and mass of elements, as well as the angle of incidence. 

DATA ANALYSIS

Micrometer Results

Table 1 shows the thickness (in millimeters) of the six Chilean stamps following TAPPI T-411 standards, a method measuring single-sheet thickness and variations in single-sheet thickness 

of paper, tissue paper, and cardboard. No mint stamps were measured. The results from the micrometer were affected by surface 

roughness, cancellations, glue, and paper and hinge remnants.

Chromaticity Results

The polygons drawn in Figure 11 represent the color gamut 

covered by all of the samples, constructed by determining the 

convex hull (CH) of the set of data points. The CH is the minimal convex set containing the data points. There are many different “colors” in the spectrometric sense, but only four in the 

perceptual sense. These results support the differentiations made 

between the two blue and the two red issues, given their clustering and overlaps. The visual determinations were made independently of the VSC 6000’s findings. 

While color expert James Allen sorted and collated the 

shades of the Chilean stamps, a number of difficulties became apparent, including the underlying paper color or the bluing of the 

Figure 9. Thermo Nicolet FT-IR with Continuum microscope.

Figure 10. Rigaku D/Max Rapid with stamps mounted for 

analysis.

Table 1. Micrometer results for 20 stamps.

Thickness Standard deviation

Stamp (mm) (mm)

Chile 1 (red) 0.1161 0.0028

Chile 8 (red) 0.1227 0.0034

Chile 2 (blue) 0.1116 0.0085

Chile 12 (blue) 0.1349 0.0069

Chile 11 (yellow) 0.1411 0.0022

Chile 13 (green) 0.1098 0.0026
2 6 • smithsonian contributions to history and technology

paper affecting the color interpretation as a tint different (generally lighter) from that identified by the VSC 6000; the roughness 

of the stamp surface identified by oblique light reflections during data collection; and stamps that were either poorly inked or 

overinked, resulting in a certain level of “blotchiness.” Canceled 

and damaged stamps, paper differences, and other printing inconsistencies also contributed to the results, and all of the stamps 

had been soaked off cover and washed before affixing them to 

the album pages. As a rule, the stamp colors suffered from the 

cleaning process; for example, the 20 centavos became altered 

to a much lighter and sometimes a bluish green (Bacon, 1902).

The color expert applied de facto fuzzy membership functions and determined color ranges (Table 2), resulting in the 

identification of color variations that, while differentiable, are 

not that distinctive. They are likely the result of batch variations 

in ink or pigments, aging effects, and possible paper color transmission effects. When considering the size of the CHs relative to 

MacAdam ellipses, it is clear different color experts might well 

disagree on which shades fit which categories as the chromaticity 

moves away from the center of the individual CH.

The 5-centavos printings were probably a bright brick red 

color rather than the current brownish red. The reason for the 

various tints is the extenders used in the ink. The 10-centavos 

modified Prussian blue stamps were originally bright blue; however, after 150 years of aging, washing of the stamps, and environmental conditions, the color has changed to a deep or deeper 

bright blue. 

An extender, also known as filler, in printing ink technology 

is a white transparent, or semitransparent, component whose 

purpose is to reduce the cost of the ink by increasing the area 

covered. It can reduce the color strength of the ink without adding any white color to it, which is useful if the pigment in the 

ink is very strong. Extenders can also be used to adjust the ink’s 

consistency and viscosity.

The most interesting stamp from the London printings is the 

1-centavo stamp. There are several tints to this currently dullish green-yellow stamp. Because of the different amounts of lead 

chromate, aging 150 years and various environmental conditions 

darken and muddy the stamp colors. These stamps are considered changelings since they have dissolved to a “greenish” tint, 

while the original color was probably goldenrod. One surprising 

discovery seen under high magnification was the red spots found 

Figure 11. CIE 1976 u′,v′ chromaticity coordinates of the London 

printing of the Chile stamps.

Table 2. Colors and shades of the London printed Chile postage stamps identified by color expert.

Printing 5 centavos 10 centavos 1 centavo 20 centavos

First London printing, 

issued 1 July 1853

Brownish red with gradations of brightness on 

blued paper (Chile no. 1)

Prussian blue with gradations of deepness on 

yellowish-white paper 

(Chile no. 2)

– –

Second London printing, 

issued May 1855

Brownish red with gradations of deepness on blued 

paper or cream-colored 

paper (Chile no. 8)

– – –

Third London printing, 

issued 1 January 1862

– – Olive yellow with shade 

variations of green and 

yellow on yellowish-white 

paper (Chile no. 11)

Dark green with gradations 

of deepness on yellowishwhite paper (Chile no. 13)

Third London printing, 

issued October 1861

– Deep blue with gradations 

of bright to deeper blue 

on yellowish white 

(Chile no. 12)

– –
number 57 • 2 7

in various quantities in every stamp (Figure 12). These spots are 

further discussed in later sections.

The 20-centavo stamp has two different tints: dark green 

and deeper green with the original color being a deep green.

It should be pointed out the VSC is a comparator and is not 

calibrated as an analytical instrument. Its results are indicative 

but not definite. As many colors are made by mixing pigments 

and organic dyes, the VSC cannot distinguish them, and its use 

for individual pigment identification may be restricted as seen in 

the limited amount of data in the infrared spectrum (Figure 13).

XRF Results

The XRF spectra from the handheld portable XRF at the 

NPM and the accumulated Artax spectra from the XRF mapping data collected at MCI can be easily compared. The greater 

sensitivity of the Artax, using a helium flush in acquiring the 

elemental maps, allows detection of more fluorescence from the 

lower energy peaks from aluminum and silicon when compared 

to the Tracer data. This is reflected in the changes in element ratios, including aluminum and potassium, seen in Table 3.

However, overall, the data obtained from the two XRF 

methods are generally quite similar. The XRF maps are very useful in identifying any anomalies present. For example, the overall XRF spectrum from Chile number 2 (Figure 14) identifies a 

copper component in the ink, suggesting the use of an azurite 

colorant [Cu3(CO3)2(OH)2]. However, examination of the map 

shows the copper is a lone area of contamination (Figure 15) 

and not a component of the ink, so we can discount azurite as 

Figure 12. Chile number 11 showing the vermilion ink as red 

spots at ×1,600.

Figure 13. The reflectance curve of Chile number 8 showing no organic red dyes present.
2 8 • smithsonian contributions to history and technology

a possible ink component. The data clearly show that both lead 

(Pb) and iron (Fe) are components of the ink. 

The 5-centavo stamps (Figure 16) show major amounts of 

calcium and iron. The inclusion of trace levels of manganese in 

addition to major iron peaks suggests the use of an iron oxide 

earth, for example, the nineteenth century Venice red (Fe2O3), 

as the primary inorganic red colorant. However, the use of red 

lead (Pb3O4) or organic red colorants cannot be eliminated. In 

addition, Prussian red, K3[FeIII(CN)6], is known to be used by 

Perkins and Bacon and is suggested by the identification of minor 

levels of potassium in the ink. 

The 10-centavo stamps as seen in Figure 14 show major 

amounts of lead and minor amounts of iron and calcium. The 

large amount of lead and iron in a blue stamp suggests the use 

of lead white (PbCO3)2·Pb(OH)2 with a Prussian blue colorant. 

It should be noted that the large amount of lead present in the 

10-centavo stamps makes it difficult to determine if sulfur is 

present due to the overlap of the sulfur K peak with the lead Pb 

M peaks at 2.3 keV. 

The 1- and 10-centavo stamps both show lead, sulfur, and 

chromate, suggesting the use of a lead chromate yellow. The mercury identified in the yellow ink suggests an identification of the 

red spots (Figure 12) visible under the microscope as vermilion 

Table 3. Element ratios of the London printed Chile postage 

stamps.

Number Pb/

Stamp averaged Fe/K K/Al S/Al S/K Cr

Chile 1 (red) 20 9.11 5.75 8.91 1.55 –

Chile 1 (red) 2 8.22 5.32 12.72 2.62 –

Chile 8 (red) 10 9.04 5.50 9.66 1.76 –

Chile 8 (red) 2 11.63 3.93 9.76 3.35 –

Chile 2 (blue) 10 50.63 1.48 – – –

Chile 2 (blue) 1 30.60 3.14 – – –

Chile 12 (blue) 10 68.07 1.22 – – –

Chile 12 (blue) 3 32.97 7.75 – – –

Chile 11 (Yellow) 10 10.76 1.64 – – 2.90

Chile 11 (Yellow) 2 4.70 10.09 – – 2.71

Chile 13 (Green) 10 95.18 0.55 – – 5.13

Chile 13 (Green) 2 18.16 3.03 – – 4.20

Figure 14. Accumulated XRF spectra of blue stamp maps by Perkins, Bacon & Co., 1853 (Chile number 2) and 

1861/2 (Chile numbers 12a, 12b, and 12c).

Figure 15. XRF map from Chile number 2.
number 57 • 2 9

or cinnabar (HgS). Figure 17 shows the results for the 1-centavo 

stamps (Chile number 11).

Infrared spectroscopy shows that the large calcium peak 

present in the yellow and blue inks is from a calcium carbonate 

filler in the inks. It is interesting to note the green ink used in 

the 20-centavo stamp contains only minor amounts of calcium, 

while significant amounts of calcium are present in the yellow 

ink. The peaks from potassium, sulfur, and aluminum present 

to varying amounts in all the stamps are likely from the use of 

alum KAlSO4. 

The analysis of the six London printed stamps of Chile 

showed several interesting ratios of elements. The lead/chrome ratios in the yellow and green inks differ slightly; the yellow ink has 

a higher amount of lead to chrome than the green ink. The ratios 

Figure 16. Accumulated XRF spectra of red stamp maps from Perkins, Bacon & Co., 1853 (Chile numbers 1a 

and 1b) and 1855 (Chile numbers 8a and 8b).

Figure 17. Sample of XRF results for Chile number 11.
3 0 • smithsonian contributions to history and technology

for the Chile 1 and 8 issues and the 2 and 12 issues are similar and 

do not show any significant differences between the two printings.

FTIR Results

In all the IR spectra there is a large contribution from the 

paper on which the stamps were printed. In cases where no gum 

or adhesive remained on the back of the stamp, a reference spectrum of the paper could be easily compared to the infrared spectrum of an inked area to identify the contributions of the paper 

(Figure 18). Infrared spectroscopy was able to identify a number 

of white pigments that were added to the inks. In all stamps calcite (CaCO3), also referred to as chalk or whiting, has been identified. In the red ink, calcite appears to be the only white pigment 

present, whereas in the blue inks, lead white (hydrocerussite) 

was used primarily, with small amounts of calcite also present. 

The cyanide bands present in the red inks vary in different 

stamps and in different locations within the same stamp. Peaks 

at 2,080, 2,060, and 2,040 cm–1 have all been identified, with 

the main peaks occurring at 2,080 and 2,060 cm–1. This is in 

agreement with the results found in the penny red stamps examined by Ferrer and Vila (2006). The peak around 2,080 cm–1 can 

also be seen in the blue and green inks, here from Prussian blue 

originally present in the inks. Unfortunately, the cyanide bands 

occurring in the 2,040–2,090 cm–1 region are not distinct enough 

to identify specific ferrocyanide and ferricyanide components. 

For example, both soluble and insoluble forms of Prussian blue, 

Fe4

III[Fe2II(CN)6

] and Fe4

III[FeII(CN)6

]

3 

and KFeII[FeIII(CN)6], are 

said to absorb at 2,080 cm–1 (Berrie, 1997). It is likely that additional work in this area may be able to further elucidate the 

initial ink components. 

In the yellow and green inks, peaks from the colorants could 

be clearly identified in the infrared spectra. Peaks characteristic of lead sulfate appear in the yellow ink, in addition to large 

peaks from calcite. The green ink contains a significantly smaller 

amount of chalk than the yellow ink, which allows the lead chromate peaks centered around 850 cm–1 to be identified. 

The ATR objective on the microscope could not be used on 

all of the stamps in the study, but use on the Chile 1 issue allowed tracking of the cyanide components of the red ink into 

the blued areas (see Figures 5 and 19). Although the blued areas 

show none of the chalk component of the ink, a cyanide band at 

2,060 cm–1 is still present. 

Although both linseed oil and beeswax are known to be 

components of the ink, most of the characteristic bands for these 

media are hidden under the absorption peaks from the paper or 

other ink components. The strong bands in the C–H stretch region, at approximately 2,890 and 2,850 cm–1, are present due to 

the hydrocarbon chains in both linseed oil and beeswax. When 

comparing the ink spectra to the paper spectra both obtained 

from all the stamps, a broad shoulder at approximately 1,730 

cm–1 is present. This can be attributed to the carbonyl groups 

present in both vegetable oils and beeswax. However, neither the 

carbonyl nor the C–H stretch absorption should be considered 

definitive proof of a vegetable oil/beeswax binder. Both calcium 

and lead fatty acid soaps, which are formed when the ink components interacted with the linseed oil and stearates in the beeswax, 

were identified in the blue inks.

XRD Results

Using an 800 μm diameter collimator, X-ray diffraction 

confirmed the identification of lead chromate (PbCrO4) in the 

yellow and green inks; in addition, it was able to confirm the 

Figure 18. Infrared spectra from front and reverse of Chile number 11 showing contributions of paper and ink.

Figure 19. The μATR-FTIR of blued ink on 1853 Perkins and 

Bacon red stamp (Chile number 1a).
number 57 • 3 1

identification of the red spots in the yellow ink as vermilion (Figure 20). As in the FTIR, calcite was identified in all four inks. 

Crystalline fatty acid soaps were identified in the red ink. XRD 

of the paper areas of the stamps examined only identified cellulose of varying degrees of crystallinity. 

DISCUSSION AND CONCLUSIONS

Nondestructive analysis of the stamps was completed using 

instruments at the Smithsonian National Postal Museum and 

the Smithsonian Museum Conservation Institute. A large-scale 

analysis (10–100 mm2) provides overall examination of ink and 

paper simultaneously, while small-scale analysis (0.01–0.1 mm2) 

allows a better discrimination between paper and ink data.

While all the techniques employed have limitations when 

used individually, complementary use of the techniques and 

comparison of the data allow for better understanding of the 

results obtained by an individual instrument as well as a more 

thorough characterization of the stamps (Table 4). Although the 

specific presence of beeswax or linseed oil cannot be determined, 

the identification of fatty acid soaps in the XRD and IR data, as 

well as the strong C–H stretch bands in the IR data, indicate a 

vegetable oil or beeswax-based binding medium was likely used. 

Whiting (calcite) was identified in all of the inks examined, 

while lead white was used additionally in the blue inks. This is 

likely due to the high tinting strength of Prussian blue, which 

requires only a small amount of the pigment to produce a deep 

blue color. When Prussian blue was used in the green ink, it was 

not accompanied by lead white. The yellow pigment used in both 

the yellow and green inks is a chrome yellow (PbCrO4). A further support for the likely original goldenrod tint of the yellow 

stamps, rather than the current muddy green-yellow tint, is the 

inclusion of a small amount of the red vermilion pigment in the 

yellow ink. 

Vermilion was not identified in the red inks used. The presence of manganese in the XRF spectra of the red stamps and the 

presence of kaolinite (Al2Si2O5(OH)4) in the IR spectra of the red 

inks suggest at least some of the red color is due to the inclusion 

of a red iron oxide (Fe2O3). Unfortunately, the generally noncrystalline nature of earth pigments meant no confirmation of 

this could be found using XRD. Although Ferrar and Vila found 

gypsum used in the penny red stamps also printed by Perkins 

and Bacon (Ferrar and Vila, 2006), no gypsum was identified in 

either the IR or XRD data. 

ACKNOWLEDGMENTS

We thank Gary Granzow for his encouragement, support, 

and research of the Perkins, Bacon & Co. Archives at the Royal 

Philatelic Society London library and the Hackney Archives, 

Figure 20. XRD data from yellow ink area of Chile number 11 stamp.
3 2 • smithsonian contributions to history and technology

which contained information on Lewis Berger & Sons, an ink 

supplier to Perkins, Bacon & Co. James Allen identified the various shades and colors of the stamps, and Harry Brittain verified 

our FTIR and XRD results using the equipment in his laboratory. 

NOTES

1. Scott numbers are from 1998 Standard Postage Stamp Catalogue—Volume 

2 (Countries C–F). The third printing had two different dates of issue: October 

1861 for the 10¢ and January 1862 for the 1¢ and 20¢.

2. Most commonly, the powder diffraction file produced by the International 

Centre Diffraction Data, Newtown Square, Pa., http://www.icdd.com (accessed 15 

January 2013).

3. The Bernard Peyton Specialized Collection of Chile (accession number 

223486), which was donated to the Smithsonian National Philatelic Collection on 

23 December 1958, consists of two albums and is a comprehensive study of the 

different color shades of the first issues of Chile from 1853–1967.

REFERENCES

Allen, J. A., and T. Lera. 2013. “The U.S. 1851 3¢ Stamp: Color, Chemistry, and 

Changes.” In Proceedings of the First International Symposium on Analytical Methods in Philately, ed. T. Lera, J. H. Barwis, and D. L. Herendeen, 

pp. 71–81. Smithsonian Contributions to History and Technology, No. 57. 

Washington, D.C.: Smithsonian Institution Scholarly Press.

Bacon, E. D. 1902. The 1853 to 1867 Issues of Chili Stamps, a Paper Read Before the Philatelic Society, London May 30, 1902. The London Philatelist, 

XI(126–128):132–139, 162–169, 187–190.

———. 1920a. The Line-Engraved Postage Stamps of Great Britain. Volume 1. 

London: Chas. Nissen.

———. 1920b. The Line-Engraved Postage Stamps of Great Britain. Volume 2. 

Appendix C, reference no. 330. London: Chas. Nissen.

Berrie, B. 1997. “Prussian Blue.” In Artists Pigments, Volume 3, ed. E. W. Fitzhugh, 

pp. 191–218. Oxford: Oxford University Press.

Blank, G. 1989. Chile: First Issues of Postage Stamps, 1853–1867. London: Royal 

Philatelic Society.

Castro, K., B. Abalos, I. Martinez-Arkarazo, N. Etxebarria, and J. M. Madariaga. 

2008. Scientific Examination of Classic Spanish Stamps with Colour Error, 

a Non-invasive Micro-Raman and Micro-XRF Approach: The King Alfonso 

XIII (1889–1901 ‘Pelon’) 15 cents Definitive Issue. Journal of Cultural Heritage, 9(2):189–195.

Cesareo, R., and A. Brunetti. 2008. X-Ray Fluorescence—Analysis of 19th Century 

Stamps. X-Ray Spectrometry, 37(3):260–264.

Chile the “Colon” Issues 1853–1867: The Joseph Hackmey Collection. 2011. 

Wiesbaden: Heinrich Köhler.

Derrick, M. R., D. Stulik, and J. M. Landry. 1999. Infrared Spectroscopy in Conservation Science. Los Angeles, Calif.: Getty Conservation Institute.

De Worms, P. 1953. Perkins Bacon Records. Volume 2: Foreign Contract. London: 

Royal Philatelic Society.

Ferrer, M., and A. Vila. 2006. Fourier Transform Infrared Spectroscopy Applied 

to Ink Characterization of One-Penny Postage Stamps Printed 1841–1880. 

Analytica Chimica Acta, 555(1):161–166.

Gálvez, J. 1964. Los Primeros Sellos de Chile, 1853 a 1867; Con Traducciones al 

Inglés y al Francés. Santiago de Chile: J. Gálvez.

Granzow, G. 2012. Line Engraved Security Printing: The Methods of Perkins Bacon 1790–1936 Banknotes and Postage Stamps. London: Royal Philatelic 

Society London.

Griffiths, P. R., and J. A. de Haseth. 2007. Fourier Transform Infrared Spectrometry. 2nd ed. Hoboken, N. J.: John Wiley & Sons.

Hahn, O., I. Reiche, and H. Stege. 2006. “Applications in Arts and Archaeology.” 

In Handbook of Practical X-Ray Fluorescence Analysis, pp. 687–700. New 

York: Springer.

Herendeen, D. L. 2011. Philatelic Shade Discrimination Based on Measured 

Colour—Corrigenda. London Philatelist, 120(1385):153.

Herendeen, D. L., J. A. Allen, and T. Lera. 2011. Philatelic Shade Discrimination 

Based on Measured Colour. London Philatelist, 120:105–117.

Infrared and Raman Users Group. 2013. http://www.irug.org (accessed 15 January 

2013).

Table 4. Characterization of the London printed Chile postage stamps.

Stamp 

number Color Year of issue FTIR results XRF results XRD results

1 Red 1853 Calcite (1400, 872); kaolinite (3600, 3695); 

cyanide peaks (2060, 2080)

Major: Fe, Ca; Minor/trace: 

Pb, K, S, P, Al

Calcite; fatty acid soaps

2 Blue 1853 Lead white (br 1400 678); Prussian blue 

(2088); fatty acid soaps (1540, 1510); 

traces of calcite (872)

Major: Pb, Fe; Minor/

trace: Ca, Al, K; Sulfur 

undetermined

Hydrocerussite; cerussite; 

calcite

8 Red 1855 Calcite (1400, 872); kaolinite (3600, 3695); 

cyanide peaks (2060, 2080)

Major: Fe, Ca; Minor/trace: 

Pb, K, S, P, Al

Calcite

11 Yellow 1862 Calcite (1400, 872); lead sulfate (627, 596) Major: Ca, Pb; Minor/trace: 

S, Cr, Hg, Fe, K, Al

Lead chromate; vermilion; 

calcite

12 Blue 1861 Lead white (br 1400 678); Prussian blue 

(2088); fatty acid soaps (1540, 1510); 

traces of calcite (872)

Major: Pb, Fe; Minor/

trace: Ca, Al, K; Sulfur 

undetermined

Hydrocerussite; cerussite; 

calcite

13 Green 1862 Lead sulfate (627, 596); lead chromate (850 

trace); Prussian blue (2086); trace calcite 

(872)

Major: Pb, S; Minor/trace: 

Cr, Fe, Ca, K, Al

Lead chromate; possible 

calcite; possible minium 

or red lead
number 57 • 3 3

Janssens, K. H. A., F. Adams, and A. Rindby. 2000. Microscopic X-Ray Fluorescence Analysis. 1st ed. New York: Wiley.

Preiss, I., and S. Robie. 1982. Radioisotope X-Ray Fluorescence in Philately. Industrial and Engineering Chemistry Product Research and Development, 

21(4):676–678. http://dx.doi.org/10.1021/i300008a034. 

Sanchez, H. J., and M. C. Valentinuzzi. 2006. Authentication of Postal Pieces 

by Spatially Resolved X-Ray Fluorescence Analysis. X-Ray Spectrometry, 

35:379–382.

Scott Publishing Co. 1997. 1998 Standard Postage Stamp Catalogue—Volume 2 

(Countries C–F). Sidney, Ohio: Scott Publishing.

Documenting Science in Philatelic Literature: 

A New Perspective

David L. Herendeen

ABSTRACT. This paper addresses how scientists in the philatelic community may 

best document highly technical work in a manner that is interesting and readable for 

laypersons—stamp collectors. After describing the different scientific aptitudes of philatelists, the paper suggests guidelines scientists might use to reduce complicated concepts to 

their essence. This is crucial if there is to be an efficient technology transfer of science into 

the mainstream hobby. Methods posed include a moderation in technical complexity and 

an increased use of visualization tools, including photos, charts, drawings, graphs, and 

more. The paper concludes with a discussion of publishing venues for scientific articles to 

reach the most appropriate audience.

AN UNUSUAL REQUIREMENT

For the past decade, the number of scientific research projects related to philately, and 

their attendant publications, has been growing steadily. The majority of this research has 

been focused on various uses of spectroscopy to analyze color, inks, cancels, and paper 

characteristics. Most of the researchers (e.g., Chaplin et al., 2004; Liston, 2005; Gill, 

2007; Odenweller, 2009a; Herendeen et al., 2011; Caswell, 2012) are professors or other 

trained scientists. This is both good and bad. The good is that the quality of the research 

is high. The bad is that many of the articles were written by these scientists for scientists.

The transfer of technology into philately has an unusual requirement: the need to 

communicate highly technical information to laypersons so they understand the basic 

ideas, importance, and potential applications of scientific results. This paper poses a 

number of methods to facilitate this transfer.

DIFFERING SCIENTIFIC APTITUDES

The education, experience, and aptitude of each individual usually determine that 

person’s level of interest in science. To set the stage for understanding how to document 

philatelic science, consider a simple model that includes three widely differing aptitudes 

for science. 

High Aptitude for Pure Science

Naturally, those with the greatest aptitude for science often enter a scientific or engineering field. Scientific investigation is normally concerned with understanding natural 

David L. Herendeen (deceased), Institute for 

Analytical Philately, Inc., P.O. Box 8035, Holland, Michigan, 49422-8035, USA. Correspondence: president@analyticalphilately.org. Manuscript received 10 April 2013; accepted 26 April 

2013.
3 6 • smithsonian contributions to history and technology

phenomena, and it is performed by and for scientists. These scientists must often invent their own “language” to communicate 

previously unknown concepts. In its purest form, science is an 

intellectual pursuit. It is not even necessary that there be a practical application of the science. For example, this was initially true 

for such important discoveries as relativity, quantum mechanics, 

and string theory.

The pursuit of pure science requires years of study and training. Scientists are dedicated and highly focused. It is not reasonable to expect laypersons either to intuitively understand or to 

exert the kind of intellectual energy necessary to grasp complex 

scientific principles. It is therefore counterproductive to communicate with philatelists in “technospeak.”

Aptitude for Technology and Engineering

Other individuals with a high aptitude for science study 

methods for applying pure science to solve “real world” problems. These are technologists and engineers. Once certain scientific principles are proven, they are often used to develop 

advanced technologies, for example, internal combustion engines, nuclear reactors, and supersonic aircraft. The technologist is not obligated to rederive basic scientific principles at each 

step but rather is obligated simply to apply them to solve specific 

problems, invent new devices, or improve upon other devices. 

This group is able to understand the pure science but always 

strives to apply it to solving specific problems.

Little Scientific Aptitude

Finally, technologies are transferred to the nonscientific 

population, those with little scientific interest or aptitude. Perhaps the most famous example of this is Teflon. A material designed for use in spacecraft became a part of the cookware in 

every kitchen. Users never asked how Teflon developed or why 

it works. They were simply happy to have nonstick cookware.

This is the most important group to reach if science is to 

become an accepted part of everyday philately.

Integrating these Groups

These different aptitudes are directly reflected in forensic philately. The First International Symposium on Analytical 

Methods in Philately (subsequently referred to as “Symposium”) 

has shown that all of these aptitudes exist simultaneously in 

philatelic research.1 Indeed, papers were presented representing all three. Most important for the future, several researchers were capable of being quickly trained in the use of forensic 

equipment. Only a few key concepts may be required to interpret simple results. It is the enumeration and transfer of these 

concepts that are required to make scientific philatelic analysis 

successful.

This is where organizations such as the Institute for Analytical Philately, Inc. (IAP) and the National Postal Museum (NPM) 

are crucial. By bringing together a multidisciplinary group of 

scientists, technologists, and managers, these nonprofit organizations can facilitate communication and technology transfer 

between scientists and philatelists.

The premier English-speaking expertizing agencies, the 

Expertizing Committee of the Royal Philatelic Society London, 

the Philatelic Foundation (New York), the American Philatelic 

Expert Committee (APEX), and the Vincent Graves Greene 

Foundation (Canada) have recently begun integrating forensic 

equipment into their procedures. This adds further impetus to 

the need for development of appropriate scientific procedures for 

philatelic forensics.

The Potential Audience

What, then, is the target audience for scientific writing in 

philately? Is it the scientific peers of the writer, of which there are 

few? Or is it members of the entire stamp collecting community, 

of which there are many?

The answer to these questions should be clear. Unlike academia or industry, the application of science to problem solving 

is not an end. Instead, it is a beginning that allows new methods 

and tools to be developed for direct application to philately. As a 

simple example, consider the comparison of two stamps, nominally the same, that appear to be different colors, not shades. 

It is easily shown (Liston, 2012) using spectrographic methods 

that the elemental makeup of the inks is different. Therefore, 

the stamps are in fact different. That is all a philatelist needs to 

know. Neither detailed knowledge of the spectrograph, nor deep 

knowledge of chemistry, nor understanding of excitation of inner 

shell electrons is needed. If later a layperson wants to be involved 

in such analyses, then naturally some training will be required. 

But to benefit or learn from technology it should not be necessary to have a Ph.D. in chemistry or physics.

In summary, the scientist must convey the value of the philatelic component of the research in as direct a manner as possible, 

using plain English in a way that makes the utility of a technique 

come alive.

THE IMPORTANCE OF 

TECHNOLOGY TRANSFER

There are several reasons it is important to direct philatelic 

science to all philatelists. These are discussed in the following 

sections.

Philately is a Hobby

Scientists should always keep in mind that philately is, first 

and foremost, a hobby. For the vast majority of enthusiasts the 

hobby is about stamps. A smaller percentage of collectors focuses on the usage of the stamps. An even smaller percentage 
number 57 • 3 7

studies the development of other aspects of postal systems. While 

it is true some philatelists are very serious, not all collectors are. 

In fact, only a very small portion of the population will ever 

know or care about hard forensic science. 

On the other hand, those who do care, including scholars, 

expertizers, specialists, and exhibitors, often have an insatiable 

need to know the truth. This may result from the need to know 

that a particular item is genuine; it may be to understand the history of stamp production—especially inks and papers—during 

a certain era; or it may be pure intellectual curiosity. There are 

perhaps 3,000–5,000 such philatelists around the world based 

on the numbers of authors and exhibitors. Of these, one estimates that fewer than 2,000 were ever involved in anything at an 

advanced scientific level either in a university or in industry. At 

the present time, IAP has about 100 members, slightly more than 

half of whom are scientists. Those remaining fall into the other 

categories but are still members of the 3,000–5,000.

The key point is probably 99% of all stamps collectors are 

not science buffs. Yet many have often wondered about colors, 

ink, papers, and gum. This group must not be forsaken if science 

is to play an important role in the future of philately.

Previous Attempts Failed

How many have ever heard of Philatelic Research Laboratories, Inc., Philatelic Research Ltd., or the Arthur Salm Foundation? Ostensibly, these were earlier attempts to bring science into 

philately. Without going deeply into their history, the first was 

the brain child of Y. Souren, a major New York stamp dealer 

from the 1920s until his death in 1949 (Souren, 1939). The second was the creation of another dealer, Roy H. White. It was 

used as a vehicle for publishing a number of studies during the 

1970s and 1980s (White, 1983). The final one, the Arthur Salm 

Foundation, was created in 1991 by the Collectors Club of Chicago using a donation from the late Arthur Salm and additional 

funding from the club (Arthur Salm Foundation, 1991).

These three entities shared two traits. First, they were not 

scientific organizations. The first two appear to have been vehicles for the proprietors to generate business opportunities. This 

in no way diminishes the fact that their founders were extremely 

talented at forensic analysis. The third, the Salm Foundation, 

with an endowment of about $50,000, was formed to conduct 

research on philatelic products. They used outside laboratories 

to perform analyses with no apparent interest in developing such 

technical capabilities permanently for the hobby.

Second, none of these organizations attempted to be inclusive or to develop an ongoing organization that would survive 

either their creators or their endowments. In other words, they 

were doomed to expire from the beginning—and they did.

A New Beginning

Why did previous attempts fail? The answer lies with organizations such as IAP and the NPM.2 IAP was formed in 2009 by 

a group of philatelists who were both scientifically trained and 

held senior management positions in industry. This nonprofit 

corporation is dedicated to funding scientific research in philately and developing new methods that will advance all areas of 

scientific philately. Equally important to both IAP and NPM is 

the dissemination of the results of this research.

The long-term goals of IAP also include forming a pool of 

human resources that can perform research and assist and train 

others in performing their own research. The NPM forensic laboratory is one place open to researchers. 

It is also hoped that the expertizing bodies in the USA, 

Canada, and Europe will become resources for further research. 

Thus, it is anticipated that a synergistic relationship will develop 

that accelerates the integration of science into the hobby.

THE IMPEDIMENTS TO 

TECHNOLOGY TRANSFER

Exactly what are the impediments that prevent widespread 

assimilation of new scientific information by the philatelic public? Several of these are discussed in the following sections.

Impenetrable Language

The first potential problem is an article or paper simply contains too much science. Is this possible? Consider a few titles of 

scientific papers from major journals in other scientific domains: 

Analytical Performance in Flow Injection–Simultaneous 

Multielement–Inductively Coupled Plasma–Optical Emission 

Spectrometry Employing a Cyclonic Spray Chamber (Hettipathirana and Davey, 1996).

The Notion of a Rational Convex Program, and an Algorithm for the Arrow-Debreu Nash Bargaining Game (Vazirani, 

2012).

Only a very small percentage of the population (even of university postgraduates) has any idea what these papers may be 

about. This is not surprising because the research is published in 

specialized journals of record in the spectrographic and computing scientific disciplines.

Why would this observation not apply to stamp collectors 

as well? Consider these titles:

Characterization of Genuine Stamps, Reprints, and Forgeries of the 1867 and 1868 Issues of the Roman States by 

Diffuse Reflectance Spectroscopy (Tyler and Peck, 1978).

Fourier Transform Infrared Spectroscopy Applied to Ink 

Characterization of One-Penny Postage Stamps Printed 

1841–1880 (Ferrer and Vila, 2006).

Do you think most philatelists will immediately read these 

papers? They would perhaps glance through the paper and look 

at the “pretty pictures.” Just maybe, if the figures and graphics 

convey easily understandable information, rather than data, the 

reader might actually risk venturing into the text.
3 8 • smithsonian contributions to history and technology

Why are titles like these effective?

The “China Clay” Varieties of the 1908–1910 WashingtonFranklin Issues (Liston, 2005).

New Zealand: Inks Used for the Early Chalon Heads (Odenweller, 2009a).

They are short, do not try to explain in the title every technique used in the research, and give an easily understood overview 

of their contents. The author hopes casual readers would not be 

frightened away before even considering reading the articles.

Too Much Data

After getting past an overly complex title, some research papers proceed to have too much data. Pages full of equations or 

spectrographs quickly blur the philatelic reader’s eye, causing loss 

of interest. Data should be reduced to the minimum necessary 

to prove the thesis of the paper. It is not unusual for a research 

project to generate many, many thousands of data items. But remember, data is not information. Information is the distillation of 

raw data into trends and conclusions that allow a phenomenon to 

be better understood and for observations to become knowledge. 

As a very simple example, consider the curve shown in Figure 1. This curve represents a physical quantity sampled at more 

than 400 different conditions for a single stamp. Now, suppose 

there were a hundred such curves. Would it make sense to show 

all 100 data sets as separate plots? Of course not. They could 

all be plotted together, as shown for only 25 curves, in Figure 2. 

What a mess. Better yet, just the envelope (the upper and lower 

limits) of the data, and their average, could be shown, as seen in 

Figure 3. Thus, it has been possible to reduce tens of thousands 

of raw data items into three easy-to-understand curves showing 

us the limits and average of the data.

This shows how powerful graphical representation of data 

can be. This will be discussed in more detail later.

FIXING THE PROBLEMS

As introduced above, the easiest way to make scientific results more understandable is to improve data visualization. Specifically, this means only the data necessary to prove the thesis of 

the paper should be shown. That does not mean nonsupportive 

data should be omitted. The results should be understandable to 

any motivated philatelist. The optimal tools should be selected to 

present the data, as discussed in the following sections.

Organizing the Paper

One of the easiest ways to improve the readability of a scientific paper is by carefully organizing the presentation of the 

Figure 1. A simple curve representing more than 400 raw data 

points.

Figure 2. Data for 25 measurements on a single plot. Hopelessly 

useless: too much data, too little information.

Figure 3. Tens of thousands of raw data points reduced to three 

easy-to-understand curves.
number 57 • 3 9

experiment, equipment, and results. Some ideas are presented in 

the following sections.

Isolating Ponderous Science

There are cases when a researcher has a great desire to add 

large amounts of scientific theory, equations, or other embellishments to a paper. Ask if the reader would be better served 

if this information appeared as appendices that can be skipped 

by readers who are neither domain experts nor interested. This 

same observation applies to explaining the type of hardware 

used to perform forensic analyses. While it is important to specify the equipment used, long lists of technical specifications from 

the manufacturers’ catalog and manual should not overwhelm 

the thesis and results of the study.

This technique of isolation can greatly enhance the layperson’s interest in a paper.

Simplifying Scientific Concepts

Whenever possible, consider simplifying complicated scientific concepts. Some of the current researchers do this successfully. Consider the following description presented by Liston 

(2012:163):

The most important aspect of this technique [X-ray 

fluorescence] is that the elemental composition of the 

ink remains the same even if there has been a significant 

chemical change of the ink. For example, oxidation or 

sulfidization from contaminants in the air or reaction 

with chemicals in the paper of the album or even light 

can cause a “color changeling.” This is true because the 

binder in the ink keeps the original layer of ink, with 

its elements, in place on the stamp even if the chemical 

nature of the ink has changed.

This description is as simple as it could possibly be. While 

there may be readers who don’t even know what an element 

is, this still represents, in the author’s opinion, an excellent explanation. Researchers should strive for this level of clarity of 

communication.

Data Visualization

In many technical papers, especially those in chemistry, 

spectroscopy, and physics, much of the data may be represented 

in figures. There are many different ways to represent data, some 

of which are described in this section. As seen earlier, the point of 

using such devices comes from the old maxim “a picture is worth 

a thousand words.”

Photographs

Photographs are a wonderful way to convey knowledge 

to the reader in a nonthreatening manner. For example, Figure 

4 shows a photo of a piece of analytical equipment. This gives 

Figure 4. Photos of hardware help reduce the mystique of new technology for the uninitiated. From Herendeen et al. 

(2011, Fig. 9). Courtesy of The London Philatelist and the Royal Philatelic Society London.
4 0 • smithsonian contributions to history and technology

the reader a chance to remove any prejudged mystique and fear 

of hardware. It is also useful to include one or more reference 

items so that the viewer gets a sense of the scale of the hardware. 

Figure 5 shows an experimenter actually dealing with samples 

during a testing procedure. This kind of photo helps convey the 

careful organization needed in detailed experimental work.

Drawings and Sketches

Drawings and sketches are often used to reduce complex 

ideas to a simplified and easily digested form. Consider Figure 

6. This little sketch actually describes, in a very simple fashion, 

the energy dispersive X-ray fluorescence (EDXRF) spectrometer. 

Given the rather intimidating name of this equipment, the layperson would probably be surprised by the ease with which the 

principles of this device can be understood. One can trust the 

scientists who have developed the theory and the engineers who 

have designed and manufactured the equipment.

Graphs

Another way to make large amounts of data understandable 

in a single glance is the graph. With the advent of spreadsheet 

software, the creation of many styles of graphs has been greatly 

simplified. One use of graphs was previously shown in Figures 1, 

2, and 3. Frequently encountered are the spectrographs that are, 

not surprisingly, the result of spectrographic analyses. A classic 

example is shown in Figure 7. This graph represents many thousands of samples taken by the EDXRF to determine the chemical 

elements in a sample.

Figure 5. Photos of actual experimentation help illustrate the detail required for high-fidelity results. From Herendeen et al. (2011, Fig. 11). 

Courtesy of The London Philatelist and the Royal Philatelic Society London.
number 57 • 4 1

Figure 7. A typical spectrograph showing two different ink compositions (one in green, the other in red) based on simple elemental analysis 

using EDXRF. This allows the differences in ink composition to be easily discerned as the chemical elements are labeled.

Figure 6. An example of a drawing or sketch used to provide a simple description of a possibly complex 

process. This is the logical design of an EDXRF spectrometer.
4 2 • smithsonian contributions to history and technology

Charts

Charts include bar, pie, scatter, area, surface, and many 

others. Generally, these charts allow different classes of data to 

be readily viewed and understood. For example, typically, bar 

charts are used to illustrate quantities such as sales by quarter or 

height by age of children. 

There are many more exotic types of charts. Consider Figure 8. This is what is called a chromaticity diagram. It is very 

difficult to express what is shown in words alone. Generally 

speaking, the small area noted by the arrow describes the various shades of color (red-orange) within the spectrum of colors 

defined by a specific color model of a large group of stamps. 

These words simply do not convey as memorable a concept as 

what is present in the drawing.

The flowchart is another useful device. It is often used to show 

the logical flow of a process. An example is shown in Figure 9.

Tables

Sometimes an author wishes to present actual numeric data. 

This may be done in tables. Normally, such tables, to be useful, 

have only a few numeric values in them. 

For example, Table 1 shows a portion of a table that shows 

how an expert identified colors based on their chromaticity coordinates (Herendeen et al., 2011, Table 1:111). The author believes tables tend to be much more useful in humanities research 

than numeric-based research because there are usually very 

large quantities of data that are being reduced to draw specific 

conclusions. Mind-numbing tables of raw data seldom communicate such conclusions effectively.

Outside Readers

One of the most important aspects of scientific research is 

to have one’s work reviewed by outside readers. The principal 

reason to use outside readers is to make certain that no simple 

errors have been made and that the paper is understandable. All 

authors are subject to the same modes of failure. For complex 

Figure 9. Logical flow of the ideal manuscript peer review process.

Figure 8. An example of a chart providing a simple view of a complicated concept. From Herendeen (2011, Fig 2). Courtesy of The 

London Philatelist and the Royal Philatelic Society London.

Table 1. Allocation of color categories (extracted from Herendeen, 2011, Table 1).

Chromaticity coordinates

Sample x y Expert allocation

P1 0.3381 0.4948 H2

P2 0.3370 0.4940 H2

P3 0.3433 0.4993 H3

P4 0.3351 0.4917 H1

P5 0.3364 0.4926 H1

P6 0.3395 0.4943 H1
number 57 • 4 3

subjects that take prolonged periods of research, the scholar is 

often so embedded in his work that a wide perspective is lost. 

Experience has shown that it is possible for small, but very important, facts to be overlooked.

Odenweller (2012b:132), in an editorial in the Collectors 

Club Philatelist, wrote

On occasion we have been asked if it would be a good 

idea to “referee” the articles that appear in the way they 

are done for scholarly journals. Usually this is not practical, either due to time constraints or for finding the appropriate referee, since the author is likely to be one of 

the most likely to know the subject best. Still, we do try 

to ask for input from other specialists when it is possible, 

sometimes while the article is being processed for print. If 

this is the case, and an answer is received too late for the 

issue, we can entertain a “response” article for the next.

The author, as one who has edited several philatelic specialty 

journals, understands the origin of this position. Few philatelic 

publications have the luxury of an article “backlog.” The production of even a quarterly journal requires a constant scouring of a 

society membership for material. When using a review process of 

any type, there is usually a time lag that can easily be intolerable.

The second objection, the difficulty of finding domain experts to act as referees, is not necessarily true, as amplified in the 

next section.

Philately is Different

Scientific papers relating to philately are different from those 

in many other disciplines because there are three domains of expertise that come into play with philatelic science. The first domain 

is the science itself. Thanks to the advent of IAP and a growth in 

scientific analyses, especially those related to spectroscopy, there 

is a growing pool of talented researchers qualified to objectively 

review such manuscripts. The second domain is the philatelic one. 

The author believes that there is always at least one additional 

expert capable of critiquing and fact-checking a research manuscript. This is similar to finding professors to serve on a Ph.D. 

committee for a candidate who is already working at the state of 

the art in some scientific field. This is, in fact, a common occurrence. The third and final domain is a reviewer who can determine 

if the manuscript is conveying useful information to readers who 

may not have a strong scientific background. Such reviewers will 

most often be scientific managers who were fighting this battle 

for many years when trying to convey extremely difficult scientific 

concepts to upper management in the corporate world.

The Procedure

The logical flow of the actual procedure for the ideal peer 

review process is shown in Figure 9, an iterative procedure including feedback loops between the reviewers and the author 

and later between the author and the publication editor. It is this 

feedback that improves publication quality.

A Real-World Example

To see how this works, consider the author’s article on the 

inverted frame postage-due stamp of Labuan (Herendeen, 2006). 

This project was quite large in scope. Without getting into great 

detail, this study required contacting many collectors, dealers, 

and expertizing groups around the world; combing thousands of 

auction catalogs; and scouring many journal articles and stamp 

publications. After two and a half years, the basic research was 

completed. The article itself was multidisciplinary in nature. It 

included a detailed history of the stamps, a comprehensive census, the use of computer graphics to reconstruct multiples, and 

statistical analysis to estimate the number of errors that may 

have been printed.

So how does one have such an article “refereed?” For this 

paper, several domain experts in British colonial stamps were 

used, a university professor was used to check the statistical formulation, and several philatelic editors were used to insure the 

quality of the manuscript.

Does such a procedure take time? Most certainly, but this 

time is well worth it when it yields a superior result.

Where to Publish Scientific Philately

Once the scientific study has been documented, exactly 

where should it be published? There are two aspects to consider 

when making this decision. The first is whether a sufficient audience of philatelists exists with enough scientific background to 

gain important insight from one’s work. The second is the philatelic subject matter.

The Collectors Club Philatelist

The Collectors Club Philatelist (CCP), until recently under 

the editorship of Robert P. Odenweller, is an excellent venue 

for publishing scientific articles. There are several reasons for 

this. First, Odenweller (2012a) noted that the CCP plans to be a 

leader in the publication of quality scientific articles. During the 

2000s, a fair number of important articles have appeared (e.g., 

Liston 2005, 2012; Lera, 2012). Odenweller’s successor, Gene 

Fricks, has indicated that he will continue supporting scientific 

articles. Fricks is a professional scientist and will be a great editor for scientific work.

The CCP has a circulation of more than 900 and a good 

penetration into major public libraries. This makes it easy for 

philatelists to access materials published in it. Others may be 

able to find material on the IAP Web site,2 at the American Philatelic Research Library,3 or through the recently formed Global 

Philatelic Library (Walton, 2012).4

The London Philatelist

The honorary editor of the London Philatelist (LP) is Frank 

Walton. The LP is the literary organ of the Royal Philatelic 

Society London (RPSL). To date, only a modicum of scientific 
4 4 • smithsonian contributions to history and technology

analysis has been presented in the pages of the LP. However, the 

RPSL now has a Video Spectral Comparator 6000 and an XRF 

spectrometer on order. These should become a source of more articles based upon optical and chemical spectroscopy in the near 

future. With a worldwide circulation of more than 2,100, this 

publication is also ideal.

The American Philatelist

The American Philatelist (AP) is the monthly magazine of 

the American Philatelic Society. The editor is Barbara Boal. Many 

years ago, the AP editorial policy changed its tone, leaning more 

to historical and thematic articles than hard-core research. Nonetheless, scientific articles have appeared occasionally over the past 

four decades (e.g., Tyler and Peck, 1978; Glazer and Dow, 1983; 

Hanneman and Hintze, 1991; Bell and Blackett, 2012).

The obvious plus for the AP is that it has a circulation of 

more than 32,000 monthly, and many philatelic scientists are 

members.

Major U.S.-Related Journals

The major U.S. specialty journals The Chronicle (U.S. Philatelic Classics Society, circulation 1,200), The United States Specialist (United States Stamp Society, circulation 1,800), and The 

Confederate Philatelist (Confederate Stamp Alliance, circulation 

~700) have large circulations and a significant number of practicing and retired scientists. For research related to U.S. material, 

these may be the best venues for articles. They have already published some of these, such as White (1989a, 1989b, 1989c). These 

are all high-quality productions with good color. The Postal History Journal would generally be most appropriate for research relating to verifying markings, cancels, and other indicia on covers.

Specialty Journals

Most specialty journals have relatively low circulations, e.g., 

100–600. With the exception of Philatelica Chimica et Physica, 

the journal of the Chemistry and Physics on Stamps Study Unit, 

these specialty groups also tend to have relatively few scientists 

as members. 

Professional Technical Journals

One should consider submitting work to the various professional journals as well as the philatelic ones. There are several 

reasons to do this. First, it raises the stature of analytical philately in the eyes of those who feel that these publications are 

a validation of the worth of research. Perhaps more important, 

there is an opportunity to expose large numbers of scientists, all 

of whom have analytical capabilities, to the fact that there are 

philatelic mysteries to be solved. Readers may think of novel approaches to solving problems exposed by published papers.

This is not an easy road, and perhaps current researchers in 

academia will be able to help pursue this area.

The Book

Finally, you can write the great book on a particular philatelic subject. For example, works that have wonderful scientific 

content include Glazer (1994) and Odenweller (2009b).

The problem with a philatelic monograph is that it is virtually impossible to tell from the title that there is any scientific 

content. Also, generally speaking, the circulation of monographs 

in today’s world is modest, and their cost is often significant. 

This is not a good combination for making maximum penetration to the potential technical audience.

Web Publishing

The final possibility is to create an electronic article that is 

hosted by a Web site. IAP will do this for members and nonmembers without charge. By using this vector, the number of possible 

worldwide readers will be increased dramatically. 

THE POWER OF GRAPHICS

The author requests that readers of this paper now go back 

to the beginning. By looking only at the section headings and 

graphics, do you know what the paper is trying to convey? If yes, 

then the paper is a success. In no, the author will go back to the 

drawing board.

CONCLUSION

This paper has described the difficulty scientific philatelists 

may have in communicating scientific results to nonscientific 

philatelists. It has identified a set of problems and suggested a 

number of solutions to them.

It is hoped this new proposed publishing paradigm will 

allow the current renaissance in scientific enquiry to flourish 

rather than wilting like other earlier attempts.

ACKNOWLEDGMENTS

The author acknowledges the following individuals who 

were kind enough to review this work: Thomas Lera, Winton 

Blount Chair of Research, Smithsonian National Postal Museum; 

Gene Fricks, incoming editor of the Collectors Club Philatelist; 

John Barwis, vice president of IAP; and W. Danforth Walker, the 

designated “layperson” to test the sanity of the manuscript.

NOTES

1. The First International Symposium on Analytical Methods in Philately was 

held at the Smithsonian National Postal Museum, 12–14 November 2012. It was 

organized by the Institute for Analytical Philately, Inc.
number 57 • 4 5

2. More information on the Institute for Analytical Philately, Inc. may be 

found at http://www.analyticalphilately.org. For the National Postal Museum, see 

http://www.postalmuseum.si.edu (accessed 18 July 2012).

3. To see what the APRL offers and to use the online catalog, see http://www

.stamps.org/About-the-Library (accessed 18 July 2012).

4. Through its portal, the Global Philatelic Library has access to 19 different 

philatelic libraries in the USA, United Kingdom, Australia, Canada, Germany, and 

Norway. See http://www.globalphilateliclibrary.org (accessed 18 January 2013).

REFERENCES

Arthur Salm Foundation. 1991. Report Number 1. Chicago: Collectors Club of 

Chicago.

Bell, R. M., and R. S. Blackett. 2012. Philately & DNA. American Philatelist, 

126(3):236–241.

Caswell, L. R. 2012. Evaluation of Forensic Methods for Overprint Analysis. Collectors Club Philatelist, 91(1):35–45.

Chaplin, T. D., A. Jurado-Lopez, R. J. H. Clark, and D. R. Beech. 2004. Identification by Raman Microscopy of Pigments on Early Postage Stamps: Distinction 

between Original 1847 and 1858–1862, Forged and Reproduction Postage 

Stamps of Mauritius. Journal of Raman Spectroscopy, 35:600–604

Ferrer, N., and A. Vila. 2006. Fourier Transform Infrared Spectroscopy Applied to 

Ink Characterization of One-Penny Postage Stamps Printed 1841–1880. Analytica Chimica Acta, 555(1):161–166. http://dx.doi.org/10.1016/j.aca.2005

.08.080. 

Gill, T. E. 2007. “Analysis of 19th Century Mexican Postage Stamps by PIXE.” 

In Proceedings of the XI International Conference on Particle Induced 

X-Ray Emission and Its Analytical Applications, pp. PI-42-1–PI-42-4. Puebla, 

Mexico: Instituto de Física, Universidad Nacional Autónoma de México.

Glazer, M. 1994. The King George V High-Value Stamps of Bermuda, 1917–1938. 

Marblehead, Mass.: Calaby.

Glazer, M., and J. Dow. 1983. X-Ray Fluorescence Investigation and Analysis of 

the 12/6 King George VI Stamps of Bermuda. American Philatelist, 97(6): 

512–515.

Hanneman, W. W., and R. E. Hintze. 1991. Gum Characterization by Infrared 

Spectroscopy. American Philatelist, 105(9):816–817.

Herendeen, D. L. 2006. Labuan 8c Inverted Frame Postage Due Stamp. London 

Philatelist, 114:3–25.

———. 2011. Philatelic Shade Discrimination Based on Measured Colour—

Corrigenda. London Philatelist, 120:153.

Herendeen, D. L., J. A. Allen, and T. Lera. 2011. Philatelic Shade Discrimination 

Based on Measured Colour. London Philatelist, 120:105–117.

Hettipathirana, T. D., and D. E. Davey. 1996. Analytical Performance in Flow 

Injection–Simultaneous Multi-element–Inductively Coupled Plasma–Optical 

Emission Spectrometry Employing a Cyclonic Spray Chamber. Applied Spectroscopy, 50(8):1015–1022. http://dx.doi.org/10.1366/0003702963905286. 

Lera, T. 2012. In the National Postal Museum Research: Scientific Equipment at the 

NPM. Collectors Club Philatelist, 91(3):174–178.

Liston, E. M. 2005. The “China Clay” Variety of the 1908–1910 WashingtonFranklin Issues. Parts 1 and 2. Collectors Club Philatelist, 84(2):105–112; 

84(3):141–146.

———. 2012. Scientific Examination of a New Venezuelan “Color Error.” Collectors Club Philatelist, 91(3):163–167.

Odenweller, R. P. 2009a. New Zealand: Inks Used for the Early Chalon Heads. 

Collectors Club Philatelist, 88(4):246–250.

———. 2009b. The Postage Stamps of New Zealand, 1855–1873: The Chalon 

Head Issues. London: Royal Philatelic Society London.

———. 2012a. Editorial. Collectors Club Philatelist, 91(2):68.

———. 2012b. Editorial. Collectors Club Philatelist, 91(3):132.

Souren, Y. 1939. Philately of Tomorrow. New York: Philatelic Research Laboratories.

Tyler, V., and G. E. Peck. 1978. Characterization of Genuine Stamps, Reprints, and 

Forgeries of the 1867 and 1868 Issues of the Roman States by Diffuse Reflectance Spectroscopy. American Philatelist, 92(6):580–587.

Vazirani, V. V. 2012. The Notion of a Rational Convex Program, and an Algorithm 

for the Arrow-Debreu Nash Bargaining Game. Journal of the ACM, 59(2):7. 

http://dx.doi.org/10.1145/2160158.2160160. 

Walton, F. 2012. Global Philatelic Library. London Philatelist, 121:196–197.

White, R. H. 1983. The Papers and Gums of United States Postage Stamps 1847–

1909. Germantown, Md.: Philatelic Research.

———. 1989a. Application of Electron Microscope and X-Ray Analysis to Identification Techniques for Stamp and Proof Papers. Part 1. United States Stamp 

Specialist, 60:187–191.

———. 1989b. Application of Electron Microscope and X-Ray Analysis to Identification Techniques for Stamp and Proof Papers. Part 2. United States Stamp 

Specialist, 60: 299–305.

———. 1989c. Application of Electron Microscope and X-Ray Analysis to Identification Techniques for Stamp and Proof Papers. Part 3. United States Stamp 

Specialist, 60:419–427.

Infrared Spectroscopic and X-Ray Diffraction 

Studies of the Typographed Confederate 

5¢ Stamps

Harry G. Brittain

ABSTRACT. It has been determined that X-ray diffraction (XRD) is a highly useful 

analytical tool for study of the paper used in the printing of postage stamps of the Confederate States of America. Through use of the technique, one may differentiate among 

different types of paper that were used in the printings, primarily through a characterization of the inorganic salts used as sizing and filling agents. When combined with attenuated total reflectance (ATR) sampling, Fourier transform infrared (FTIR) spectroscopy 

can be used to study the pigments used in the printing inks, and with comparison with 

suitable reference standards, FTIR-ATR spectra can be used to identify the pigments 

used in these inks. The utility of XRD and FTIR-ATR will be illustrated using the 5¢ 

blue typographed postage stamps featuring the portrait of Jefferson Davis that were issued by the Confederate States of America during 1862–1863 (Scott CSA-6 and CSA-7). 

Through study of appropriate examples, it has been found that FTIR-ATR spectroscopy 

can be used to distinguish between the printing ink used by the De La Rue Company 

(London, England) and by the Archer & Daly Company (Richmond, Virginia). It has also 

been found that XRD can distinguish between paper supplied by De La Rue and paper 

obtained locally by Archer & Daly. The nondestructive protocol that has been developed 

is to first use FTIR-ATR to determine whether a given stamp should be classified as being either CSA-6 or CSA-7. Subsequently, XRD is used to confirm that a CSA-6 stamp 

is printed on London-sourced paper or whether a CSA-7 stamp is printed on Londonsourced or Richmond-sourced paper.

INTRODUCTION

The first stamps printed by the Confederate States of America (CSA) were produced 

by the Hoyer & Ludwig and the J. T. Paterson companies using a lithographic process 

(Dietz, 1929: chapter 5). It was always the intent of the Confederate postmaster general, John H. Reagan, to print stamps using steel engraving whose quality would equal 

those printed by the United States Federal government, but logistics prevented him from 

achieving his goal until the spring of 1863 (Kimbrough and Bush, 2011:90–98).

In October of 1861, the Confederacy sent Major Benjamin F. Ficklin to England to 

contract for various supplies needed by the CSA Post Office Department to produce its 

own high-quality stamps (Dietz, 1929: chapter 7). The CSA needed to acquire a sufficient 

quantity of printed stamps to hold them over until it could obtain the plates and materials for production of locally printed stamps. Accordingly, an agreement was reached 

with the Thomas De La Rue & Co., Ltd., in London for typographed stamps and plates 

of two denominations of stamps. The first shipment did not make it through the Federal blockade, but the second shipment was placed aboard the blockade runner Giraffe

Harry G. Brittain, Center for Pharmaceutical 

Physics, 10 Charles Road, Milford, New Jersey, 

08848, USA. Correspondence: hbrittain@center

pharmphysics.com. Manuscript received 10 April 

2013; accepted 26 April 2013.
4 8 • smithsonian contributions to history and technology

(later renamed the Robert E. Lee), which successfully evaded the 

blockade and landed its cargo in Wilmington, North Carolina, in 

February of 1862 (Kimbrough and Bush, 2011).

The central motif of the 5¢ blue stamp (Scott catalog CSA6) (Scott Publishing Co., 2012) is a portrait of Jefferson Davis 

that was designed and engraved by Jean Ferdinand Joubert De 

La Ferte (Kimbrough and Bush, 2011:103–107). The stamps 

were printed from one 400-subject electrotype plate and were 

delivered in half sheets of 200 divided by a vertical gutter into 

two panes of 100 each. The imperforate stamps were printed on 

thin, white, woven, hard-surface paper with colorless gum, and 

the impressions were clear and distinct. Because these stamps 

were printed by De La Rue in England, these stamps are known 

as the “London Print” issue.

Using the De La Rue plates brought through the blockade, 

more 5¢ stamps were typographed in Richmond, Virginia, by 

Archer & Daly, so these stamps are known as the “Richmond 

Print” issue. Two kinds of paper were used for the Richmond 

printings, one being the thin, white, woven, hard-surface paper 

imported from England (which in this paper will be identified 

as CSA-7L) and the other being an inferior paper manufactured 

locally (which will be identified in this paper as CSA-7R). In 

addition, the ink used in the printing of the typographed Richmond prints was obtained locally, and this resulted in a range of 

apparent colors that spanned all shades of blue.

Although the Richmond printings were printed from the 

same De La Rue plate, one can generally distinguish them from 

the London printings by the overall coarser impression of the 

image. However, it can be somewhat difficult to distinguish the 

early Richmond prints from the later prints, especially when the 

stamps were printed on the imported De La Rue paper. Since 

these distinctions can sometimes be subtle, it was appropriate to 

develop analytical techniques that could be used to establish a 

protocol for the differentiation of London prints (CSA-6) from 

Richmond prints (CSA-7) as well as the two Richmond prints 

(CSA-7L and CSA-7R) from each other.

In order to determine what types of forensic analysis could 

be used to differentiate the various typographed 5¢ blue Jefferson Davis, authentic reference stamps (shown in Figure 1) were 

studied using Fourier transform infrared (FTIR) spectroscopy 

coupled with attenuated total reflectance (ATR) and using X-ray 

diffraction (XRD). It was found that the elemental components of the printing ink could be characterized using the FTIR 

method, while the composition of the paper could be deduced 

Figure 1. Typographed 5¢ blue Jefferson Davis stamps that served as references during the course of method validation.
number 57 • 4 9

using the XRD method. Subsequently, substantial numbers of 

stamps of all three types were analyzed using the same technologies to verify the rugged nature of the analytical procedure.

TECHNOLOGY PRIMER

Since the work is heavily based on forensic analytical technology, it is appropriate to first provide an outline and basis for 

the methodologies used.

X-­Ray Diffraction

The various techniques associated with X-ray diffraction 

(XRD) deal with physical properties related to the crystalline nature of solids (Brittain, 1995: chapter 7). The external examination of crystals reveals that well-formed crystals are completely 

bounded by flat surfaces, and it has been established that the surfaces of crystals depend critically on structural arrangements of 

the atom molecules in the crystal. In fact, when high-quality crystals are available, one can use single-crystal XRD to determine 

the exact structure and intermolecular bonding in the crystal.

The basis for the XRD effect lies in the fact that the threedimensional pattern of atoms or molecules in a crystalline 

solid is such that it can act as a diffraction grating to light (i.e., 

X-rays) having wavelengths of the same order of magnitude as 

the spacings between planes of atoms or molecules in the crystal. 

All X-ray diffraction techniques are ultimately based on Bragg’s 

law, which describes the diffraction of a monochromatic X-ray 

beam impinging on an atomic or molecular plane. Parallel incident rays strike the crystal planes at an angle (denoted as q) 

and are then diffracted at the same angle. The observation of 

reinforcement requires that the path difference of the impinging beam (i.e., the distance between molecular planes, known as 

the d spacing) be equal to an integral number of wavelengths. 

The scattering angles can be correlated to the spacings between 

planes of molecules in the lattice by means of Bragg’s law:

nl = 2d sin q,

where n is the order of the diffraction pattern, l is the wavelength 

of the incident X-ray beam, d is the distance between planes in 

the crystal, and q is the angle of beam diffraction. 

Stamps, of course, are not crystals, but either their ink or 

underlying paper can contain crystalline components capable of 

diffracting X-rays. As a result, the technology used to study the 

XRD of powdered solids can be easily applied to the study of the 

crystalline materials present in a stamp.

To measure the XRD of a powder, a randomly oriented sample is prepared so as to expose all the planes of a sample and is 

then irradiated with a monochromatic X-ray beam. In one measurement mode, the scattering angle is determined by slowly rotating the sample and using a scintillation counter to measure the 

angles of diffracted X-rays with respect to the angle of the incident 

beam (Klug and Alexander, 1974). The XRD pattern will therefore 

consist of a series of peaks detected at characteristic scattering angles. To measure the XRD pattern of a stamp, one conducts the 

same experiment but simply situates the stamp so that its surface is 

in the same plane as would be used for a powdered sample.

Since every crystalline compound is defined by a unique 

structure, each will yield a unique and characteristic XRD pattern. As a result, the XRD pattern of a substance can be taken as 

a “fingerprint” of that substance and can therefore be used for 

qualitative identification of materials. In practice, one obtains 

the XRD pattern of reference materials, and a positive identification of that material in an unknown sample can be made if it can 

be determined that the two diffraction patterns are equivalent.

In this work, XRD patterns were obtained using a Rigaku 

MiniFlex powder diffraction system equipped with a horizontal 

goniometer operating in the q/2q mode. The X-ray source was 

nickel-filtered Ka emission of copper (1.54184 Å). As shown in 

Figure 2, the stamps were pressed against the sample holder in 

the goniometer and were scanned over the range of 3.5–40° 2q at 

a scan rate of 0.5° 2q/min. The intensity scale for all diffraction 

patterns was normalized so that the relative intensity of the most 

intense peak in the pattern equaled 100%.

Infrared Spectroscopic Analysis

The patterns of intramolecular motion existing in molecules 

are characterized by repetitious oscillations of atoms about the 

center of gravity of the molecule, and these correlated motions 

are termed the vibrational modes of the molecule. Energies 

Figure 2. Interior view of the X-ray diffractometer, illustrating the 

goniometer and the mounting relationship of a studied stamp with 

the X-ray source (extreme left of the figure) and the detector (the 

cylindrical object at the right side of the figure). Image courtesy of 

the author.
5 0 • smithsonian contributions to history and technology

associated with the lowest-energy vibrational modes of a chemical compound will lie within the range of 400–4,000 cm–1, and 

transitions among these modes therefore fall into a region of the 

electromagnetic spectrum denoted as the midinfrared region. Infrared absorption spectroscopy is a highly useful technique for 

the physical characterization of solids, and its utility has been 

amply demonstrated in a wide variety of applications (Brittain, 

2006: chapters 7 and 8). For a variety of experimental reasons, 

the acquisition of high-quality infrared absorption spectra appropriate for the characterization of substances is now almost 

universally performed using Fourier transform technology. As a 

result, the technique is referred to as FTIR spectroscopy. 

The principles underlying the absorption of infrared energy 

by molecules can be understood using a simple example. Consider a bent molecule consisting of three atoms, such as water 

(H2O), which would be capable of undergoing a variety of bending and stretching motions. For example, a symmetric mode of 

water would be the simultaneous motions of the end hydrogen 

atoms and the central oxygen atom in a symmetric stretching of 

the bonds. Also possible is an asymmetric stretching vibration 

arising from compression of one bond and a stretching of the 

other bond as well as a bending vibration consisting of an opening and closing of the bond angle.

However, in order for these molecular motions to be initiated, the water molecule must absorb infrared energy, and that 

energy must exactly match the energy required to effect a change 

in the pattern of molecular motion. Since every molecule possesses only a finite number of molecular vibrational modes, a 

molecule can absorb only a finite number of discrete infrared energies. Each of these will correspond to the energy of a particular 

vibrational mode of the molecule, and the sum total of infrared 

absorptions is termed its absorption spectrum.

One of the outcomes of spectroscopic theory is that the energy of a particular vibrational mode is determined primarily 

by two factors. One factor is the strength of the intermolecular 

bonds involved in the vibration, and the other factor is the mass 

of the atoms involved. Consequently, the vibrational energy of 

every molecular group will fall within a fairly narrowly defined 

range, and correlation tables that relate molecular properties and 

absorption energies are well developed (Socrates, 2001). One 

often sees infrared spectra divided into two regions, one being 

termed the “fingerprint” region (400–2,300 cm–1) where groups 

of similar atomic masses undergo absorption and the other being 

termed the “high-frequency” region (2,500–4,000 cm–1) where 

hydrogen is one of the atoms undergoing absorption. 

While the energy associated with a particular molecular vibrational mode can be roughly understood, the exact value of 

that energy will be strongly influenced by the rest of the molecule 

whose motions couple into the vibrational mode of interest. As 

a result, every molecule will have its own characteristic and defining absorption spectrum, and this enables one to use infrared 

absorption spectroscopy for identity testing. The conduct of an 

infrared identification study proceeds in much the same manner 

as does an XRD investigation. The FTIR spectra of appropriate reference materials are obtained, and these are compared to 

the spectrum of the unknown sample. When equivalence in peak 

energy between reference and sample is obtained, one can be assured that the peak in the sample can be attributed to that of the 

compound constituting the reference.

Probably the most useful sampling method for FTIR spectroscopy is that of attenuated total reflectance (ATR). Here, 

infrared radiation is passed through a crystal at an angle that 

causes the light to undergo total internal reflection. At each reflection, the radiation penetrates a small distance beyond the crystal 

surface so that the internally reflected energy will be attenuated 

at those frequencies corresponding to changes in molecular vibrational states of whatever is held in physical contact with the 

crystal. The advantage of the ATR technique is that it requires 

effectively no sample preparation, since one simply clamps the 

analyte onto the surface of the crystal with moderate pressure 

to ensure a sufficient degree of optical contact. The internal reflectance process does not permit the infrared beam to pass very 

deeply into the sample, so the ATR sampling method permits one 

to effectively study only the outermost layers of a sample.

In the present study, Fourier transform infrared absorption 

spectra were obtained at a resolution of 4 cm–1 using a Shimadzu 

model 8400S FTIR spectrometer, with each spectrum being obtained as the average of 40 individual spectra. The data were acquired using the attenuated total reflectance sampling mode, in 

which the samples were clamped against the ZnSe crystal of a 

Pike MIRacleTM single-reflection horizontal ATR sampling accessory. This particular ATR sampling device enables one to study an 

approximate 1 mm2 area of a stamp and is illustrated in Figure 3.

Figure 3. View of the attenuated total reflectance sampling accessory used to obtain FTIR spectra of the portion of stamp surface 

directly under the pressure clamp. In the illustration, the stamp has 

actually been mounted upside down in order to demonstrate the 

small spot size studied in each measurement. Image courtesy of the 

author.
number 57 • 5 1

RESULTS AND DISCUSSION

Study of the Paper Used in Printing

of the Csa-6 and Csa-7 Issues

In the first half of the nineteenth century in America, the 

only source of papermaking fibers was linen and cotton rags, 

and the production of paper from wood pulp represents a technology not widely available until after the end of the Civil War 

(Sutermeister, 1954: chapter 1). Collected rags were cleaned as 

well as could be, cut into pieces about 2–4 inches square, and 

then placed in kettles where they were heated with chemicals that 

destroyed any coloring and rendered the pieces into a state where 

they could be pulverized into the component fibers that consisted 

entirely of cellulose (Sutermeister, 1954: chapter 2).

A very similar process is used today to produce a substance 

known as microcrystalline cellulose (MCC), which has found 

extensive use as an inactive *ingredient in pharmaceutical tablet 

formulations (Rowe et al., 2009:129–113). To make MCC, one 

starts with purified cotton and treats it with dilute solutions of 

mineral acids. The intermediate product is purified and filtered 

and eventually processed into a dry powdered form. The nature 

and structure of microcrystalline cellulose has been studied at 

length, and it has been found that FTIR spectroscopic methods 

are well suited for the differentiation of cellulose derivatives 

(Langkilde and Svantesson, 1995). As part of the present work, 

it has been found that microcrystalline cellulose is an excellent 

model compound upon which a variety of characterization studies can be based.

Figure 4 contrasts the FTIR absorption spectrum of microcrystalline cellulose with the corresponding spectra obtained 

from the margins of the reference stamps, and Figure 5 contains 

the X-ray diffraction patterns of the same regions of the same 

stamps. It is immediately clear from the nearly identical nature 

of the stacked FTIR spectra of Figure 4 that FTIR spectroscopy 

cannot be used to differentiate between London and Richmond 

paper. However, Figure 5 demonstrates that XRD analysis can 

differentiate between London and Richmond paper, since the 

XRD of Richmond paper (CSA-7R) contains contributions from 

crystalline components that the London paper (CSA-7L) does 

not contain. In fact, the paper used by De La Rue consists of 

the same solid-state form of cellulose as does microcrystalline 

cellulose.

In order to identify the crystalline component of the Richmond paper, a number of materials were wet slurried into microcrystalline cellulose, the products were allowed to air-dry, and 

then they were subjected to XRD analysis. As shown in Figure 

6, the entire crystalline response in the XRD of Richmond paper 

can be attributed to the presence of kaolin (a commonly encountered form of clay) as a filler/sizer in the locally sourced paper. It 

Figure 5. X-ray diffraction patterns of microcrystalline cellulose 

and the corresponding patterns obtained on the margins of the reference stamps Image used with the permission of The Confederate 

Philatelist.

Figure 4. Infrared absorption spectra of microcrystalline cellulose 

and the corresponding FTIR spectra obtained on the margins of the 

reference stamps. Image used with the permission of The Confederate Philatelist.
5 2 • smithsonian contributions to history and technology

is concluded from this study that the locally sourced paper used 

in the Richmond printings contained kaolin clay as the filler/sizer 

agent.

Therefore, the presence or absence of the kaolin component 

in the X-ray diffraction pattern of a typographed 5¢ blue Jefferson Davis stamp can be used to determine whether the paper 

used in the printing was sourced from De La Rue in England or 

whether it came from a local source in Richmond.

Studies of the Csa-6 and Csa-7 Stamp Surfaces

Before the results of studies conducted on the CSA-6 and 

CSA-7 reference stamps can be discussed, it is first appropriate 

to briefly provide some of the general characteristics of the ink 

used for typographic printing (Ellis, 1940). Typography consists 

of printing from raised characters or plates, where the paper is 

pressed against a printing form that consists of the image cast in 

positive relief. For job press printing, the paper to be printed is 

obtained as single sheets, and the image is created by pressing the 

entire sheet against the form at the same time. The plates used 

for typography are produced from an engraved plate, in which an 

image is etched onto a copper sheet using a chemical process. Since 

the duplicate plates can be manufactured at will from the original 

engraved plate, their use is preferred for extensive printing runs.

Typographic inks must be matched to the paper on which 

the printing is to be conducted or else the quality of the image 

will suffer. When printing with hard-faced paper, the printer will 

need to use more pressure to ensure good transfer of the image 

but not so much pressure that the ink squeezes out of the printing form. Suitable inks should possess as heavy a body as the 

paper stock will permit and should be almost buttery in nature 

to achieve satisfactory distribution over the plate. 

In typical ink production, the pigments are first ground in 

oil or varnish; this mixture is then ground into a vehicle; and 

finally, the mixture is diluted in a medium that facilitates the 

workability of the ink. Because the typographic inks used in the 

Civil War era were oil based, their drying was not instantaneous 

and the vehicles used were chosen to make the drying process 

most efficient. European vehicles mainly consisted of mixtures 

of linseed oil and rosin, and the English practice was also to 

admix some whale oil into the vehicle for economic reasons 

(Ellis, 1940:197–199).

The drying process that causes the oil-based inks used in 

typographic printing to dry entails oxidation of the unsaturated 

groups in the oils, resulting in polymerization reactions that yield 

a dried ink film that adheres to the paper (Ellis, 1940: 224–226). 

In general, typographic inks undergo minimal chemical reaction 

with the paper on which they are printed.

Figure 7 contrasts the X-ray diffraction patterns of microcrystalline cellulose along with the corresponding diffraction 

patterns obtained from the faces of the reference stamps. It is 

Figure 6. X-ray diffraction patterns of microcrystalline cellulose, a 

3:7 mixture of MCC and kaolin, and the CSA-7R paper. Image used 

with the permission of The Confederate Philatelist.

Figure 7. X-ray diffraction patterns of microcrystalline cellulose 

and the corresponding patterns obtained on the faces of the reference stamps Image used with the permission of The Confederate 

Philatelist.
number 57 • 5 3

immediately obvious from a comparison of Figures 5 and 7 

that the XRD pattern of the stamps is completely determined 

by the composition of the paper and that the XRD patterns do 

not contain any contribution from the printing ink. This finding 

confirms that XRD analysis can be used to distinguish between 

Richmond prints on London paper and Richmond prints on 

Richmond paper. However, it is equally clear that XRD analysis 

cannot be used to distinguish between CSA-6 stamps and CSA-7 

stamps printed on De La Rue paper.

Figure 8 contains the infrared absorption spectra of microcrystalline cellulose along with the corresponding absorption 

spectra obtained from the faces of the reference stamps. Examination of the figure reveals a number of differences between the 

spectra of the CSA-6 and the CSA-7 stamps as well as a high 

degree of similarity between the spectra of the CSA-7L and CSA7R stamps. For reasons that will become apparent in the following discussion, the spectral differences can be classed into three 

contributions, which have been marked in the figure.

Feature I of Figure 8 consists of a single absorption band, 

characterized by an absorption maximum of approximately 

2,090 cm–1. The energy of this band enables its assignment as 

being due to the symmetric stretching mode of a cyanide group, 

which leads to the conclusion that the ink of the CSA-6, CSA-7L, 

and CSA-7R stamps contained Prussian blue. This compound 

has a chemical formula that can be written as FeK[Fe(CN)6] and 

exhibits an intense blue color. To illustrate the identification, 

Figure 9 contains the FTIR spectrum of Prussian blue adsorbed 

onto microcrystalline cellulose, along with the FTIR spectra of 

the CSA-6 and CSA-7L reference stamps.

Feature II of Figure 8 actually consists of two absorption 

bands, a sharp band at approximately 665 cm–1 and a much 

broader band at approximately 1,000 cm–1. These absorption 

bands are associated with the presence of a single species, which 

has been identified as talc. As evident in Figure 10, the broad talc 

absorption band has a significant overlap with the main cellulose 

absorption but is evident in the spectra as a shoulder on the lowenergy side of the cellulose absorption.

At this point in the analysis, several conclusions can be deduced from the data presented thus far. The printing ink used for 

the CSA-6 stamps and for both CSA-7 issues consists of a mixture of Prussian blue (acting as the blue pigment) and talc (acting 

as the white pigment). It is clear that the actual color of a given 

stamp must depend on the relative amounts of blue and white 

pigment used to prepare the ink, and thus one may obtain a variety of shades of blue in stamps that contain varying proportions 

Figure 8. Infrared absorption spectra of microcrystalline cellulose 

and the corresponding FTIR spectra obtained on the faces of the 

reference stamps with the key analytic regions marked. Image used 

with the permission of The Confederate Philatelist.

Figure 9. Infrared absorption spectra of microcrystalline cellulose, 

Prussian blue absorbed onto MCC, and the FTIR spectra obtained 

on the faces of the CSA-6 and CSA-7L reference stamps. The position of the Prussian blue peak has been marked, and it corresponds 

to feature I of Figure 8. Image used with the permission of The Confederate Philatelist.
5 4 • smithsonian contributions to history and technology

of the two pigments. However, the pigment composition of the 

ink cannot be used to distinguish between London prints and 

Richmond prints.

Since typographic inks require the use of an oil phase as the 

vehicle, a number of vegetable oils were ground into microcrystalline cellulose, and the resulting mixture was subsequently oxidized with hydrogen peroxide. While these preparations could 

account for the hydrocarbon absorbance bands of feature IIIB of 

Figure 8, it was not possible to obtain the absorption bands of 

feature IIIA. However, oxidized proteins do exhibit absorption 

bands in this region, and therefore, preparations were made in 

which animal fat (commercial lard and beef fat) was ground into 

microcrystalline cellulose, and the mixtures were oxidized with 

hydrogen peroxide. As shown in Figure 11, the inclusion of oxidized oily animal fats in microcrystalline cellulose was successful in reproducing the absorption bands of features IIIA (1,535 

cm–1) and IIIB (2,580 and 2,515 cm–1).

It is concluded that the printing ink used for both types of 

CSA-7 stamps contained a significant amount of oxidized animal fat, and the nonvolatile part of this oily fat still remains in 

the stamps. The oil used in mixing the ink that was used in the 

printing of the CSA-6 stamps must have been much more volatile 

than the fat/oil used for the Richmond prints, as there was very 

little residual nonvolatile component evident in the FTIR spectra 

of these stamps. Given the practice at the time, it is most probable that this oil was derived from a vegetable origin and was 

probably linseed oil. The studies have demonstrated that FTIR 

spectroscopy can be used to distinguish between London prints 

and Richmond prints on the basis of the residual oil/fat remaining in the printing ink.

The results of the FTIR analysis of the inks used in the various printings of the typographed 5¢ blue Jefferson Davis stamps 

are most succinctly summarized in Figure 12, where the FTIR 

spectra obtained from the faces of the reference stamps can be 

simulated by the superimposition of the FTIR spectra of microcrystalline cellulose and the identified components in the corresponding printing inks. The FTIR spectrum for a theoretical 

CSA-6 stamp was simulated by numerically averaging the spectra of MCC containing talc and MCC containing Prussian blue, 

while the spectrum for a theoretical CSA-7 stamp was simulated 

by averaging the spectra of MCC containing talc, MCC containing Prussian blue, and MCC containing oxidized beef fat.

Figure 10. Expanded infrared absorption spectra of microcrystalline cellulose, MCC containing talc, and the FTIR spectra obtained 

on the faces of the CSA-6 and CSA-7L reference stamps. The positions of the talc peaks have been marked, and these correspond to 

features IIA and IIB of Figure 8. Image used with the permission of 

The Confederate Philatelist.

Figure 11. Expanded infrared absorption spectra of microcrystalline cellulose, MCC containing oxidized beef fat, and the FTIR 

spectra obtained from the faces of the CSA-6 and CSA-7L reference 

stamps. The positions of the talc peaks have been marked, and these 

correspond to features IIIA and IIIB of Figure 8. The feature in the 

MCC-OXID fat trace marked by the filled circle is due to residual 

unoxidized fat. Image used with the permission of The Confederate 

Philatelist.
number 57 • 5 5

CONCLUSIONS

The forensic analysis of typographed 5¢ blue Jefferson Davis 

stamps that were issued by the Confederate States of America 

has revealed a number of distinctive features that enable one to 

differentiate among the various subtypes. The analytical process 

requires a measurement of both the X-ray diffraction pattern 

and the infrared absorption spectrum of a given stamp in order 

to make the correct identification.

The first printings of the stamps (CSA-6) were made in 

London by the De La Rue Company and were made using ink 

and paper that was sourced in London. Collectors have usually 

recognized these stamps by the superior quality of their images, 

which undoubtedly came about by good matching of paper and 

ink by De La Rue. Using the forensic tools described in this 

paper, an analyst can identify these stamps on the basis of their 

XRD pattern (which contains features due to cellulose only, with 

no peaks associated with the presence of kaolin) and their FTIR 

spectra (indicative of Prussian blue and talc pigments but essentially lacking a contribution from residual oil).

The initial stamps printed in Richmond by the Archer & 

Daly Company (CSA-7 L) were made using ink that had been 

mixed locally on paper provided by De La Rue. The images on 

these stamps are not as good as the images of stamps printed 

in London by De La Rue, and this represents the lower-quality 

matching of ink and paper. The analyst can identify these stamps 

by means of their XRD pattern (which contains features due to 

cellulose only, without peaks associated with the presence of kaolin) and their FTIR spectra (indicative of Prussian blue and talc 

pigments but now exhibiting a significant contribution from residues associated with oxidized animal oil or fat).

When the supply of London-sourced paper was exhausted, 

additional printings of 5¢ blue Jefferson Davis stamps (CSA-7R) 

were made using the same locally mixed ink and locally sourced 

paper. These stamps usually feature the lowest-quality images, 

which are associated with poor matching of ink and paper. These 

stamps are identifiable on the basis of their XRD pattern (which 

contains features due to cellulose and significant peaks due to the 

presence of kaolin in the paper) and their FTIR spectra (indicative of Prussian blue and talc pigments and exhibiting a significant contribution from residues associated with oxidized animal 

oil or fat). For additional information on this issue please see 

Brittain (2013). 

ACKNOWLEDGMENTS

I thank Jerry Palazolo for his loan of the CSA-6 reference 

block used in this work. Special thanks are also due to Thomas 

Lera and Patricia A. Kaufmann for their encouragement, review, 

and support of the approach I have taken for the forensic analysis of Confederate stamps.

REFERENCES

Brittain, H. G. 1995. Physical Characterization of Pharmaceutical Solids. New 

York: Marcel Dekker.

———. 2006. Spectroscopy of Pharmaceutical Solids. New York: Taylor & Francis.

———. 2013. Forensic Studies of Stamps Issued by the CSA—Part I: the Typographed 5-Cent Blue Jefferson Davis Issues. The Confederate Philatelist, 

58(2) April–June 2013: 5–15.

Dietz, A. 1929. The Postal Service of the Confederate States of America. Richmond, Va.: Dietz Printing.

Ellis, C. 1940. Printing Inks: Their Chemistry and Technology. New York: Reinhold.

Kimbrough, J. L., and C. L. Bush. 2011. Collectors Guide to Confederate Philately.

2nd ed. Benbrook, Texas: printed by the authors.

Klug, H. P., and L. E. Alexander. 1974. X-Ray Diffraction Procedures for Polycrystalline and Amorphous Materials. 2nd ed. New York: Wiley-Interscience.

Langkilde, F. W., and A. Svantesson. 1995. Identification of Celluloses with FourierTransform Mid-infrared, FT-Raman and Near-Infrared Spectrometry. Journal of Pharmaceutical and Biomedical Analysis, 13:409–414. http://dx.doi

.org/10.1016/0731-7085(95)01298-Y. 

Rowe, R. C., P. J. Shesky, and M. E. Quinn. 2009. Handbook of Pharmaceutical 

Excipients. Washington, D.C.: American Pharmaceutical Association. 

Scott Publishing Co. 2012. 2012 Specialized Catalogue of United States Stamps. 

Sydney, Ohio: Scott Publishing.

Socrates, G. 2001. Infrared and Raman Characteristic Group Frequencies. Chichester: John Wiley & Sons.

Sutermeister, E. 1954. The Story of Papermaking. Boston, Mass.: S. D. Warren.

Figure 12. Infrared absorption spectrum simulated for a theoretical CSA-6 stamp (obtained by averaging the spectra of MCC containing talc and MCC containing Prussian blue) and the spectrum 

simulated for a theoretical CSA-7 stamp (obtained by averaging the 

spectra of MCC containing talc, MCC containing Prussian blue, and 

MCC containing oxidized beef fat). Also shown are the FTIR spectra 

obtained on the faces of the CSA-6 and CSA-7L reference stamps.

Forensic Analysis of Great Britain 1858–1879 

1d Plate 77 Stamps on Cover

Abed H. Najjar

ABSTRACT. In 2003, the author obtained an 1865 cover franked with three Great Britain 1858–1879 1d plate 77 stamps (SG 43). If genuine, this is a very valuable and historically significant philatelic item. Discoveries of plate 77 stamps are always met with 

suspicion because they are so rare and have often been the subject of attempted fakery. 

This paper presents a detailed scientific study of this cover and the stamps. It begins by 

presenting a compilation of possible methods that might be used for faking the plate 77 

stamps. It then develops an analysis plan that carefully examines each possibility. Appropriate analytical equipment is identified for each step in the process. Finally, the stamps in 

question are subjected to rigorous testing. The majority of the testing was performed by 

state-of-the-art, independent laboratories in the United Kingdom and the United States. 

Many different analyses were employed. These included optical and scanning electron 

microscopy, X-ray fluorescence spectroscopy, Raman spectroscopy, and more. The paper 

then presents the results of these analyses and the conclusions drawn from them. All of 

these data were reviewed by outside forensic experts in order to validate the scientific 

procedures. Two anomalies that arose during testing are discussed, and hypotheses are 

posed to account for them.

INTRODUCTION

An 1865 part cover (Figure 1), which was sent from Guernsey to Brussels, was written in the hand of the famed literary figure and playwright Victor Hugo, who resided at 

Hauteville House in Guernsey. Hugo lived on the island between 1855 and 1870. The 

letter, which was dated 27 November 1865, is addressed to his publishers La Croix Verboeckhoven in Brussels. This fact was confirmed by Mr. Adrien Legendre, specialist in 

books and manuscripts, Sotheby’s Paris, who confirmed as follows: “In my opinion, the 

handwriting on the envelope is Victor Hugo’s.”1 This cover will henceforth be referred to 

as the Victor Hugo cover.

The cover, sent from Guernsey to Hugo’s publishers in Brussels, was franked with 

three examples of the iconic Great Britain 1858–1879 1d stamp showing a plate number 

77. The stamps were canceled with the Guernsey 324 duplex dated 27 November 1865. 

The cover also carried a “PD” mark in red and was hand stamped with the ANGLETERE/

AMB. OUEST2- TPO mark and the BRUXEL arrival circular date stamp of 28 NO 65.

Because only a handful of accepted examples of this iconic stamp are known to exist, 

it is understandable the discovery of three used examples of this rarity on a part cover 

would be treated with much skepticism by the philatelic world. The purpose of this paper 

is to describe the analytical methods used to determine whether these stamps are genuine.

Abed H. Najjar, Bramble Cottage, Mount Pleasant, Porton, Wiltshire, SP4 0NA, UK. Correspondence: abed@btconnect.com. Manuscript received 

10 April 2013; accepted 26 April 2013.
5 8 • smithsonian contributions to history and technology

The accepted and provenanced stamps showing a plate 

number 77 have always been considered by the philatelic world 

to have been printed from plate 77. There was never a reason to 

question this fact, and with so few examples known there was 

never a need to research them.

Illustrated in Figure 2 are images of two of the accepted 

plate 77 stamps. These are the unused stamp BA (indicated 

by the letters next to the words “ONE PENNY”), now in 

the Tapling collection, and the used example stamp PH, the 

Fletcher copy, both in the philatelic collection at the British 

Library.2

The discovery of the 1865 Victor Hugo cover franked with 

three examples showing a plate number 77 has shed a completely 

new light onto the origin of these rare and iconic stamps from 

Great Britain. Comparing the position of the corner letters of 

the three stamps and the presence of a major plate flaw confirms 

these three stamps originated from plate 73.

The image in Figure 3 is that of the imprimatur stamps 

from plate 73. The stamps in Figure 4 are from the Victor Hugo 

cover.3 The arrow indicates the distinct flaw under the letter “S” 

in the top right box on stamp SK. This flaw is mirrored on stamp 

SK (Figure 4) from the Victor Hugo cover, which shows a plate 

number “77,” and the corner letters are identical in their positions on both stamps.

These features undoubtedly indicate that the printers, Perkins, Bacon & Co., must have reengraved some impressions on 

plate 73 with the plate number “77” clearly before 27 November 

1865, the date the three stamps were canceled, and in view of the 

great rarity of this trio must have then corrected them back very 

soon afterward using the plate 73 transfer roller to their original 

plate number 73. Plate 73 continued to print stamps until early 

1868, printing a total of 529,900 sheets.

Figure 1. Victor Hugo cover.

Figure 2. Left: Great Britain 1858–1879 1d red plate 77, BA, unused, the Tapling Collection, Great Britain section, page 28. Right: 

plate 77, PH, used, the Fletcher Collection, volume 81, page 2. Courtesy of the British Library Philatelic Collection.

Figure 3. Plate 73 imprimatur stamps SK and SL. ©The British 

Postal Museum and Archive, 2012.
number 57 • 5 9

The discovery of this remarkable cover, which is franked 

with three stamps that undoubtedly show interesting philatelic 

anomalies, necessitated in-depth research into all the accepted 

plate 77 stamps. 

For the purpose of this discussion, this paper will be divided 

into two sections: first, a comprehensive scientific investigation 

to rule out the possibility of faking or counterfeiting these three 

stamps and second, research into plate 77 and the accepted 

stamps showing a plate number 77 with discussion on why and 

how the reengraving was carried out and the possible reasons for 

producing “plate 77” stamps in this way.

THE COMPREHENSIVE SCIENTIFIC 

INVESTIGATIONS

What is in question is the following: have three stamps been 

manipulated and altered in five different locations to the extent 

of altering five printed figure “3”s into five faked figure “7”s; 

have the paper fibers in these five small areas been disturbed, 

moved, or altered; and has any foreign ink been used in order to 

carry out this faking process? 

Having examined these stamps the moment they were discovered using a light microscope at ×100 magnification and a 

UV light, no evidence whatsoever has been found of any faking, 

fiber disturbance, evidence of painting, or any other attribute 

that would indicate that these stamps have been manipulated. 

In order to obtain an endorsement from the expert philatelic 

bodies, the stamps were first presented to the Royal Philatelic 

Society London (RPSL)4 and then to the Philatelic Foundation of 

New York (PF)5 for an expert opinion (Figure 5). 

The RPSL Expert Committee issued a certificate of opinion, 

number 194446 dated 13 September 2006, which stated “stamps 

are not from plate 77 but have been faked in each case using a 

stamp from plate 73.” On 3 October 2006, the RPSL reiterated 

its opinion by stating the plate 73 numbers had been modified 

into 77s through a “cut and paste” method.

The PF Expert Committee issued certificate number 457736 

dated 6 November 2007, which stated “The stamps are not from 

plate 77, rather the second digit of each stamp has been altered 

to resemble a 7.” The PF expert responsible for this opinion believes this was done through “abrading to un-inked paper and 

painting.” The certificate is hand-stamped in red with the words 

“ALTERED OR COUNTERFEIT.” 

These two opinions, which allege that the stamps had been 

faked, necessitated scientific analysis, the only route by which 

one can establish their validity.

It is worth mentioning that the alleged alteration would have 

to have been carried out five times on the five visible 7s on three 

stamps, on most of which the cancel falls over the second “7.” 

This faking would need to have been done on an area that does 

not exceed 2 mm in width, with the downstroke of the number 

7 measuring 0.6–0.8 mm (Figures 6 and 7). This is a very small 

area indeed for such complicated faking work to be carried out.

In order to establish the stamps have not been tampered 

with, the Victor Hugo cover and the three “plate 77” stamps 

were subjected to a wide variety of scientific examinations by renowned organizations that used state-of-the-art scientific equipment. The services of two independent forensic scientists, Mr. 

Robert Radley, who specializes in the field of document tampering, and Professor Alan Jamieson, both of the Forensic Institute,6

were also employed.

The following possible methods of alteration were 

investigated:

Removing stamp design elements:

• inlaying (i.e., cut and paste),

• scraping,

• powder blasting or laser obliteration, and

• chemical erasure, partial or complete.

Adding stamp design elements:

• retouching small areas and

• retouching the whole “diamond.”

Table 1 summarizes the various possible methods by which 

the stamps could have been altered and the various scientific examinations that were used in order to determine their validity.

THE SCIENTIFIC METHODS USED 

TO ESTABLISH NONTAMPERING

Scanning Electron Microscopy Surface

Analysis of the Paper Fibers

Scanning electron microscopy (SEM) is a form of microscopy that allows for the large magnification of an area, providing an almost three-dimensional image, making the analysis of 

Figure 4. Stamps SK and SL from the Victor Hugo cover.
6 0 • smithsonian contributions to history and technology

an image a much easier task. SEM uses an electron beam to 

trace over the surface of an object, dislodging electrons from the 

surface, which are in turn attracted by a secondary electron detector. This produces an image by registering different levels of 

brightness on a monitor.

SEM provided by Reading Scientific Services Ltd. (RSSL)7

was used to study the surface of the right-hand “7”s to see if 

there were any fiber disruption or the addition of foreign paper 

fibers, and as can be seen in Figure 8, the surface is completely 

untouched.

The two SEM images in Figure 8 are from stamp SL on the 

Victor Hugo cover. These clearly show the paper fibers are matted together and completely intact and undisturbed.

The SEM image in Figure 9 is the left-hand “77” on stamp 

SK, shown in backscattered mode. The heavy elements forming 

the printing ink show up brightly within the diamond. It is important to note that both “7”s show similar “dark” features. If 

the right-hand figure “7” originated from a cleaned or a bleached 

figure “3,” then the figure “7” would not have been as clear and 

Figure 5. The PF and RPSL certificates.

Figure 6. Images of (top) the figure 73 from a plate 73 stamp and 

(bottom) the figure 77 from stamp SK on the Victor Hugo cover.
number 57 • 6 1

definitive as it appears as existing elements from the ink would 

still be present. Furthermore, there is no indication of any previous number being present.

If the figure “7” had been derived from a figure “3” as 

shown on the left, then the areas marked with arrows on the 

SEM image would appear as bright spots where the ink from the 

figure “3” would have been.

Figure 10 shows two photomicrographs of the right-hand 

figure “7” from the right panel from stamp SK. The image on 

the left was taken by Professor Gene Hall at Rutgers University, 

and that on the right was taken by the RSSL. The identical features of the left-hand “7”s can be seen between both images. It 

is also interesting to note that the small area of disturbed fibers 

in the center of the diagonal of the figure “7” clearly illustrates 

the fact that had the area been disturbed in order to alter the 

number, then such a feature would be prevalent throughout the 

diamond area.

X-­Ray Microfluorescence

X-ray microfluorescence (EDXRF) is a nondestructive 

method for detecting and analyzing the elements in inorganic 

substances. The XRF spectrometer measures the individual component energies of the X-rays emitted when the sample is irradiated with an X-ray beam. A spectrum is produced that depicts 

those elements found in a specific area.

EDXRF was used by both Professor Gene Hall and the RSSL 

in order to analyze the elemental components of the ink used to 

print the stamps. Both the right-hand and left-hand “7”s were 

analyzed in order to look for similarities or differences together 

with a normal plate 73 stamp for comparison.

Figure 11 is a plot from an EDAX International (Mahwah, 

N.J.) micro EDXRF Eagle II spectrometer used by Professor 

Gene Hall. EDXRF revealed the diamond inked area around 

the second “7” in plate number “77” contained the same elements (Hg, S, Pb, Ca, K, Al, and Si) as in the diamond inked area 

around the first “7” with additional elements of barium (Ba) and 

Figure 7. Image of the figure “3” from a plate “73” stamp and 

the figure “7” from stamp SK on the cover. A black outline has been 

drawn around the “7” and superimposed in the same location in the 

figure “3” diamond in order to show which areas need alteration 

and painting. It is clearly evident that the whole area needs to be 

completely altered in color, with some red areas needing to become 

“colorless” indicated by the yellow arrows and others needing to 

become “red” indicated by the black arrows.

Table 1. Analytical methods evaluated.

Modification type

Analytical method

Microscopy Near-visible light Spectroscopy Profilometry

(digital

Optical microscopy)

Scanning 

electron Ultraviolet Infrared EDXRF Raman

Inlaying P P P P P

Scraping P P P

Powder blasting or laser obliteration P P P

Chemical erasure P P P P P

Retouching small areas P P P P P P P

Retouching the entire diamond P P P P P
6 2 • smithsonian contributions to history and technology

chromium (Cr) in a spot location and was not homogenously 

distributed around this diamond inked area. The elements Ba 

and Cr were not found in the diamond area around the first “7” 

in the plate numbers “77” and “73” examined.

Both “7”s showed that identical elements were used for the 

printing ink. In addition, the right-hand “7” showed extra trace 

elements of chromium, barium, and phosphorus, which can only 

be regarded as plate contaminants originating from the platemaking process. 

Raman Spectroscopy

Raman spectroscopy is another nondestructive method of 

analyzing the inorganic components in the printing ink. The 

Figure 8. SEM images of the paper fibers of stamp RL from the Victor Hugo cover.

Figure 9. Right: Backscattered SEM image of stamp SK from the Victor Hugo cover. Note that all the uninked colorless 

areas appear dark on the image. Left: The red arrows indicate the area where the existing red ink must be altered/removed in 

order to produce a colorless figure “7” from the existing figure “3.”
number 57 • 6 3

difference between this and EDXRF is that Raman excites molecules rather than atoms. It works by irradiating molecules 

using light from a laser beam. The irradiated molecules will 

produce Raman scattering, which is measured and identified. 

Raman can determine the chemical compound that these elements belong to. This is only possible if the chemical compound 

is in a reasonable concentration and the compound is a high 

Raman scatterer.

Raman spectroscopy was used by Professor Gene Hall to 

analyze the molecular components of the ink used to print the 

stamps. Both the right-hand and left-hand “7”s were examined 

in order to characterize similarities and/or differences.

A Renishaw (Hoffman Estates, Ill.) system 1000 Raman microscope equipped with a Leica microscope was used to analyze 

the chemical composition of the pigments in the printing inks used 

on the stamps. Raman scattering in the stamps was produced by 

excitation with a 785 nm diode laser. The beam size of the laser 

was 2 μm, using a ×50 objective lens, and the laser power at the 

sample surface was reduced to 15 mW to prevent any damage due 

to burning of the stamps. Emphasis was focused on areas around 

the second “7” diamond area, which showed the presence of additional elements of Ba and Cr from the EDXRF analyses.

Raman analyses revealed the red pigment in the printing ink 

was composed of vermilion (HgS) and red lead (Pb2O3). Unfortunately, the chemical compound associated with Ba that was 

determined by EDXRF could not be identified. Chromium, the 

trace element also found using EDXRF, was identified as lead 

chromate; this was not homogenous or part of a faking ink, according to Professor Gene Hall. 

The Raman scan in Figure 12 shows the presence of lead chromate in the sample point on the second “7” from a stamp on the 

Victor Hugo cover. The red/orange trace shows the sample point 

from the stamp on the cover. The blue trace shows the Iconofile 

cinnabar cold and the black trace, the lead chromate (Aldrich) 

standard. Since the sample point has only traces of lead chromate, 

they show only as small, but significant, “bands” in the scan.

The band at 842 cm–1 of the lead chromate, which must be 

very strong, is particularly weak in this case, as can be seen in 

the trace in Figure 12, indicating that this compound is present 

in minute trace quantities.

The Raman plot in Figure 13 expands the right-hand side of 

the sample shown in Figure 12. The red/orange trace shows the 

standard for vermilion (HgS), while the two blue traces show the 

red color in a plate 73 stamp AB reference copy (upper trace) and 

a plate 77 stamp on the Victor Hugo cover (lower blue trace). 

Vermilion was used to print both reference stamp AB and the 

diamond area of the second “7” from the Victor Hugo cover. 

Profilometry/Topography

Profilometry was used to study the topography of the surface and to look at the figure “7” in three dimensions. In this 

way one can eliminate the possibility that faking has taken place, 

through paper fiber disruption and painting. Furthermore, a recessed “7,” if seen, could be produced only via impact, as with a 

surface relief printing process. The work was carried out at the 

RSSL using a Keyence VHX-600E digital microscope.

The resulting images (Figures 14 and 15) are astounding. 

Not only can one see the right-hand figure “7” as recessed, but 

enlargements show that the paper fibers are totally untampered 

and, as can be seen from the images, run in and out of the figure 

“7,” changing in color as they do. Furthermore, even bigger enlargements show the white fibers of the “7” totally devoid of any 

ink particles, colored or “bleached.”

Figure 11. EDXRF comparison of red ink around the first (blue 

trace) “7” and around the second (red trace) “7” in the plate number 

“77.” Notice the appearance of Ba and Cr in the second “7.”

Figure 10. Photomicrographs of the stamp SK on the Victor 

Hugo cover. The black arrows indicate the area of the minute 

paper disturbance.
6 4 • smithsonian contributions to history and technology

Figure 12. Raman spectra comparison diamond area around second “7” in plate “77.”

Figure 13. Raman spectra comparison of red ink on the diamond area around the second “7” 

and “3” in plate numbers “77” and “73.”
number 57 • 6 5

Infrared Light

Infrared luminescence and reflectance can be used to show 

the effect of any chemical treatment. Infrared light from an IR 

source and from a comparator was used to observe any differences between the two “7”s. An ACO Electronics QDX-630BE-2 

Questioned Document Examination System was used for these 

observations.

The infrared image (Figure 16) of stamps SK and SL is seen 

at 695 nm. The right-hand “7” in each label shows up darker 

than the right-hand “7.” This anomaly was observed by myself, 

Professor Allan Jamison of the Forensic Institute, and Mr. Robert 

Radley of the Forensic Document Laboratory. While it certainly 

did not mean faking, this anomaly did require addressing and an 

explanation. For this observation to be deemed as faking, several 

other factors must also be observed in order to confirm that the 

stamps were faked, factors such as fiber disruption, faking inks, 

abrading, painting, chemical manipulation, or the insetting of 

paper. Clearly, even from the most basic of observations it was 

confirmed this did not happen.

Figure 14. Depth composition analysis of the top of the right-hand 

“7” from stamp SL from the Victor Hugo cover. Such a recess of 

a colorless area can be produced only through impact between the 

plate and the paper at the time of printing and cannot be produced 

through faking.

Figure 15. Micrograph showing top section of magnified “7” on RHS of stamp SL from the Victor Hugo cover.
6 6 • smithsonian contributions to history and technology

The scientific evidence has confirmed that there was a total 

lack of any tampering with the paper fibers or the application of 

any faking ink. This must mean that the trace elements of barium 

and chromium must have been introduced during the reengraving 

process that was carried out on the plate in the right-hand diamond 

area on which the number was altered from a figure “3” into a figure “7.” The already existing left-hand figure “7,” which was not 

altered, does not show the presence of these trace elements.

Ultraviolet Light

High- and low-intensity ultraviolet light was also used to 

examine the stamps. Such a process may show if the areas under 

question have been chemically treated or have been retouched.

There were no differences seen between the two “7”s under 

UV light (Figure 17). This image was viewed at a wavelength of 

365 nm using an ACO Electronics QDX-630BE-2 Questioned 

Document Examination System.

Microscopy

Optical microscopy is another useful way of examining 

these stamps, bearing in mind the far more elaborate methods 

that were used. Using light microscopy at magnifications of up 

to ×140, no fiber disturbance was noticed. As we can see from 

Figure 18, which was obtained from a printed area of stamp SK 

at a magnification of ×100, the paper fibers are matted and very 

much interwoven, and any tampering, abrasion, scraping, or removal of these fibers would undoubtedly be clearly seen under 

this magnification. 

CONCLUSION

Conclusions of the Experts

The following conclusions, summarized in Table 2, have 

been extracted from the five reports obtained from the five scientific experts and expert groups who have examined the stamps 

first hand. It is clear they are unanimous in their conclusions.

1. Professor Gene Hall, Rutgers University8

“I found no evidence to support the hypothesis that 

paper fibers were removed or added to the second ‘7 diamond region’ on all three stamps. In addition, the chemistry of the inks surrounding all ‘7s’ are identical except 

for differences in concentration.”

2. Mr. Robert Radley, the Forensic Document Laboratory9

“I find no evidence of substance to significantly support 

the proposition that the stamps in question have been 

modified by an obliteration of a numeral ‘3’ from a ‘plate 

73’ stamp and subsequent alteration of the ‘3’ to a numeral ‘7’. The technical difficulties in modifying a ‘plate 

73’ stamp to a ‘plate 77’ stamp are immense and from a 

detailed examination of the cover in question, I find the 

combined evidence is inconsistent with such a procedure 

having been adopted.”

3. Professor Allan Jamieson, the Forensic Institute10

“Therefore, in the absence of evidence to the contrary, 

the scientifically logical conclusion is that the stamps 

have not been ‘faked.’”

4. Mr. Tom Ray, Microscopy Laboratory Manager, Reading Scientific Services Ltd.11

“I can confirm that by using a range of microscopy techniques (i.e. stereo light microscopy and scanning electron 

microscopy using secondary and back-scattered imaging 

modes), we found no evidence in terms of fiber disruption 

(such as deliberate tamper by scraping, cutting or adding 

fibers) during topographical examination of the second 

‘7 diamond’ regions on all three stamps. In conclusion, 

Figure 16. Infrared image of stamps SK and SL from the Victor 

Hugo cover. The right-hand figure “7” can be seen as a darkened 

area (circled in red).

Figure 17. Ultraviolet image of stamps SK and SL from the Victor 

Hugo cover.
number 57 • 6 7

Figure 18. The image on the right is a ×100 enlargement of a small area (left, black arrow) from the top of the 

right-hand “7” of the SK stamp from the Victor Hugo cover. The general matted appearance of the paper fibers at this 

magnification is clearly visible, and any fiber disturbance would also be visible under this magnification.

Table 2. Summary of the analytical results.

Modification type

Analytical method

Microscopy Near-visible light Spectroscopy Profilometry 

(digital 

Optical microscopy)

Scanning 

electron Ultraviolet Infrareda EDXRF Raman

Inlaying No fiber 

disruption

No fiber 

disruption

n/a n/a No chemical

difference

n/a No fiber disruption

Scraping No fiber 

disruption

No fiber 

disruption

n/a n/a n/a n/a No fiber disruption

Powder blasting or 

laser obliteration

No fiber 

disruption

No fiber 

disruption

n/a n/a n/a n/a No fiber disruption

Chemical erasure n/a n/a No visible 

difference

No visible 

difference

No chemical

difference

No chemical

difference

No fiber disruption

Retouching small 

areas

No visible 

difference, no 

feathering

No visible 

difference, no 

feathering

No visible 

difference

Note 1 Note 1 Note 1 No visible difference, 

no feathering

Retouching the entire 

diamond

No visible 

difference

No visible 

difference

n/a n/a No chemical

difference

No chemical

difference

No visible difference

aThe fluorescence noted under infrared light was confirmed by EDXRF and Raman spectroscopy to be from chromium found near the second 7s of all three Hugo cover 

stamps. As discussed in the text, this is believed to have been a contaminant introduced in the printing process.
6 8 • smithsonian contributions to history and technology

no evidence was found of the addition or bleaching away 

of additional layers of pigment in order to change a ‘3’ 

into a ‘7’, or any fiber disruption (e.g. through deliberate tamper by scraping, cutting or the addition of fibers) 

during depth composition examination of the second ‘7 

diamond’ regions on any of the stamps examined. Again, 

there is no evidence that extra layers of pigment have 

been added in order to convert a ‘3’ to a ‘7’. Individual 

fibers from the paper can be traced, again showing no 

evidence of tamper.”

5. Dr. Hans Hagemann, University of Geneva12

“Further inspection of the paper fibers do not suggest 

any mechanical action (scraping) on the stamps, in agreement with the observations in the ‘Hall’ report.”

Plate 77 Research

There is no doubt the three stamps on the Victor Hugo 

cover show a plate number 77 that originated from plate 73. The 

corner letters match, and the flaw in the “S” box of stamp SK is 

common on both the stamp and the imprimatur proof.

The fact that there is no evidence of tampering can only 

mean that Perkins, Bacon & Co., the printers of this issue, altered the plate numbers on some impressions from plate 73 to 

a number 77. 

This procedure was certainly irregular, so why do it? Perhaps it was one of the following reasons:

• a failed experiment at a temporary repair or marker 

number,

• a misunderstanding between the printers and plate makers,

• an unauthorized act at Perkins, Bacon & Co.,

• an effort to make a collectable stamp, or

• a mixture of these.

In fact, 66 impressions on plate 73 are documented in both 

the Perkins, Bacon & Co. printing records and the Inland Revenue records as having been reentered. 

As far as the origin of stamps showing a plate number 77, 

my research has revealed that there are only two possibilities for 

how these stamps came into existence (Najjar, 2008a, 2008b, 

2009a, 2009b, 2009c). 

According to the Inland Revenue document IR79/79, pages 

41 and 42, held at the National Archives, plate 77 was not registered or put to press, and no sheets were printed from it when 

the issue went to press in March 1864. The plate was rejected in 

a letter from Ormond Hill, secretary at the Board of the Inland 

Revenue, to the printers Perkins, Bacon & Co. dated 7 February 

1863 and was defaced in February of that year. 

The first possible origin is from the rejected imperforate and 

ungummed trial sheet(s) printed over a year before this issue was 

put to press. The sheet(s) that should have been destroyed would 

have had to be stored, then perforated, gummed, and released 

amongst the ~13.2 billion stamps printed but not before someone knowing their importance removed the four known unused 

examples from the top of the sheet. This gives us odds of finding 

a used example, say, stamp PH from the one trial sheet released 

to the public, as high as 1 in 13.2 billion. 

If these stamps did originate from the trial sheet(s), then one 

would expect the impression to be pristine and the plate numbers on 

all stamps to look identical in shape and position. They would also 

exactly match the roller impression from which they originated. 

However, close examination of all the accepted stamps showing a 

plate number “77” reveals that they do not (Figures 19 and 20).

Figure 19. Great Britain 1858–1879 1d red plate 77, an uninked impression taken from the transfer roller, the 

Board of Inland Revenue Stamping Department Archive, list 4, volume 12; plate 77, BA, unused, the Tapling Collection, Great Britain section, page 2 and plate 77, PH, used, the Fletcher Collection, volume 81, page 2. The black 

arrows indicate the two dashes next to each figure “7” on the roller impression. These are a fundamental feature 

of the master die yet are absent on both stamps BA and PH. Courtesy of the British Library Philatelic Collections.
number 57 • 6 9

In fact, I have examined thousands of these stamps from 

every known plate, and the shape and position of the plate number do not vary in any way apart from the expected inking vagaries on some. This, however, is not the case with the accepted 

plate 77 stamps.

The right-hand column of Figure 20 shows the two dashes 

against each number “7” present on the roller impression, which 

are absent on both stamps BA and PH (black arrows), and the 

short and misshapen figure “7”s (yellow arrows). The left-hand 

column shows the dissimilar figure “7”s and, most important, 

the position on the intersection on which they fall (yellow arrows). These could not have originated from a trial sheet produced from this roller impression.

The second possible origin is through reengraving some 

existing plates with the number “77.” Although this was quite 

an incredible procedure adopted by Perkins, Bacon & Co., this 

is a valid possibility because the existing plate 77 stamps show 

anomalies that cannot be explained by the trial sheet theory but 

can be explained only by reengraving. 

The anomalies in the figure “77” on all the accepted plate 

77 stamps cover are as follows:

• None of the figure “77”s match each other in shape and 

position as they should if they had originated from one 

roller impression.

• They lack a fundamental feature that appears on the 

master die.

• They show signs of wear that cannot be so had they originated from pristine trial sheets.

There are 13.2 billion stamps matching their plate numbers 

in shape and position, yet the few accepted stamps originating 

from the alleged proof sheet are all different. Why?

The alteration of the plate number to a number “77” could 

have been done by hand engraving directly on the plate, which 

would have been carried out either by the movement of the metal 

within the diamond area in order to produce the figure “7” or by 

the insertion of a plug on which the new number was engraved. 

Both methods have been replicated in the laboratory, proving 

that such an action could have easily been done by the master 

engravers of that time.

My research into the 1858–1879 issue and the origin of plate 

77 stamps, the imprimaturs and the roller impressions, plate 73 

and both the documented and undocumented plate repairs, the 

scientific evidence, and other matters relating to the Victor Hugo 

cover are fully published on my Web site.13

There is no doubt that the discovery of the Victor Hugo 

cover has caused a major controversy amongst philatelists and 

philatelic experts, a few of whom opted for the faking option in 

view of the incredible rarity of this major philatelic item and the 

way that these “plate 77” stamps were produced.

However, had it not been for my unwavering belief that the 

stamps and cover were completely genuine, the extensive use of 

state-of-the-art forensic science and scientific equipment and the 

involvement of internationally recognized forensic scientists, all 

of whom and without exception have found the stamps to be 

completely untampered with, then an extraordinary world-class 

philatelic gem of the greatest importance and the unique and 

most revealing research that it has generated would have been 

sadly buried for all time.

NOTES

1. Adrien Legedre, email message to author, 21 May 2012.

2. The British Library, 96 Euston Road, London, NW1 2DB, UK. http://www

.bl.uk/, accessed 28 January 2013.

3. The British Postal Museum and Archive Freeling House, Phoenix Place, 

London, WC1X 0DL, UK. http://www.postalheritage.org.uk/, accessed 28 January 

2013.

4. The Royal Philatelic Society London, 41 Devonshire Place, London, W1G 

6JY, UK. http://www.rpsl.org.uk, accessed 28 January 2013.

5. The Philatelic Foundation is located at 341 West 38th Street, 5th Floor, 

New York, New York, 10018, USA. http://www.philatelicfoundation.org/ (accessed 28 January 2013).

6. The Forensic Institute—Glasgow, Baltic Chambers 50 Wellington Street, 

Glasgow, Lanarkshire, G2 6HJ, UK. http://www.theforensicinstitute.com, accessed 

28 January 2013.

7. Reading Scientific Services Ltd., Reading Science Centre, Whiteknights 

Campus, Pepper Lane, Reading, RG6 6LA, UK. http://www.rssl.com/, accessed 28 

January 2013.

Figure 20. Left- and right-hand-side plate number “77” from the plate 77 roller 

impression plate 77 stamps BA and PH, respectively.
7 0 • smithsonian contributions to history and technology

8. Gene S. Hall, Ph.D., Professor of Analytical Chemistry, Rutgers–State University of New Jersey, Department of Chemistry and Chemical Biology, WrightRieman Laboratories, letter dated 1 April 2010.

9. Robert W. Radley, forensic handwriting and document examiner, M.Sc., 

C.Chem., F.R.S.C., F.S.Soc.Dip., F.A.E., R.F.P., the Forensic Document Laboratory, 

Macartneys, Kings Road, Silchester, Reading, RG7 2NS, UK, report on Plate “77” 

Stamps, dated 22 July 2009. 

10. Report of Professor Allan Jamieson, B.Sc. Ph.D., CBiol FSB, Director 

of the Forensic Institute, Glasgow, UK, Consideration of the Evidence Relating to 

Stamps, dated 19 July 2012.

11. Mr. Tom Ray, Technical Specialist, Microscopy Laboratory manager, 

RSSL, letter dated 30 March 2010 and Examination and Analysis of Three Penny 

Reds—Penny Red 77, report dated 29 February 2012.

12. Dr. Hans Hagemann, Department of Physical Chemistry, University of 

Geneva, 30 Quai Ernest Ansermet, CH-1211 Geneva 4, Switzerland, letter dated 

5 October 2010. 

13. The Victor Hugo Cover–Plate 77 Web site. http://1dplate77.com, accessed 10 February 2013.

REFERENCES

Najjar, A. H. 2008a. Great Britain: The 1858–59 1d Rose-Red Plate 77. Collectors 

Club Philatelist, 87(5):269–284.

———. 2008b, Great Britain: The 1858–59 1d Rose-Red Plate 77 Questions and 

Possible Answers with Conclusion. Collectors Club Philatelist, 87(6):333–

345.

———. 2009a, Great Britain: The 1858–59 1d Rose-Red Plate 77, a Discovery 

That Raises Questions, GB Journal, 47(4):25–38.

———. 2009b, Great Britain: The 1858–59 1d Rose-Red Plate 77 Questions (Part 

2), GB Journal, 47(5), 98–112.

———. 2009c, Great Britain: The 1858–59 1d Rose-Red Plate 77 Questions (Part 

3), GB Journal, 47(6), 131–142.</refs>

SUGGESTED READINGS

Bacon, M. V. O., and E. Denny. 1920. The Line-Engraved Stamps of Great Britain. 

Volumes 1 and 2. London: Chas. Nissen.

de Worms, P. 1953. Perkins Bacon Records. Volume 2. London: Royal Philatelic 

Society.

Melville, F. J. 1916. Postage Stamps in the Making. London: J&H Books.

Moubray, J., and M. Moubray. 1992. British Letter Mail to Overseas Destinations 

1840–1875. London: Royal Philatelic Society.

Osborne, H. 1949. British Line Engraved Stamps: Repaired Impressions. London: 

H. F. Johnson.

Stanley Gibbons Channel Islands Postal History Catalogue. 2008. London: Stanley 

Gibbons.

Stanley Gibbons Collect British Stamps. 2012. London: Stanley Gibbons.

Stanley Gibbons Commonwealth and British Empire Stamps 1840–1952. 2006. 

London: Stanley Gibbons.

Vila, A., and N. Ferrer. 2006. Fourier Transform Infrared Spectroscopy Applied 

to Ink Characterization of One-Penny Postage Stamps Printed 1841–1880. 

Analytica Chimica Acta, 555:161–166.

Wiggins, W. R. D., ed. 1962. The Postage Stamps of Great Britain Part Two, the 

Perforated Line Engraved Issues, London: Royal Philatelic Society.

Williams, L.N. 1993. Encyclopedia of Rare and Famous Stamps. Geneva: David 

Feldman.

Williams, L. N., and M. Williams. 1949a. Stamps of Fame. London: Blandford Press.

———. 1949b. Fundamentals of Philately, State College, Pa.: American Philatelic 

Society.
The U.S. 1851 3¢ Stamp: 

Color, Chemistry, and Changes

James A. Allen and Thomas Lera

ABSTRACT. This paper describes research performed on the United States 3¢ 1851 

stamp (Scott USA numbers 10, 10A, 11, and 11A) both to determine analytically the 

elemental composition of their printing inks and to demonstrate quantitative measures 

of their color with state-of-the-art technology. The principal analytical tools for performing these analyses were X-ray fluorescence spectroscopy (XRF) and optical reflectance 

spectroscopy. A relatively simple technique for determining significant elements in the ink 

pigment is presented based on XRF analysis. The resulting elemental data are then correlated with documented chemical formulae and visual properties of pigments and inks 

of the period. This correlation allows the likely and predominant pigments used in the 

manufacture of the inks to be inferred. From this, a general approach for the evaluation 

of ink colors in terms of likely pigments is offered. The use of rigorous scientific analyses 

led to results that challenge long-held historical beliefs about particular inks used for 

these stamps. The results were surprising and not predictable. The older hypotheses, 

while posited using a technical approach, did not have access to the types of analytical 

tools available today.

HISTORICAL BACKGROUND

The United States 1851 3¢ stamp is an important and popular philatelic collectible. 

It has been the subject of significant research for a long period of time. The stamps are 

distinguished for collecting purposes by the characteristic positions of the specific plate 

from which they were produced. Furthermore, over 1 billion stamps were produced during a 10-year period from 28 original or modified plates. This resulted in many plate 

varieties and color shades (Granzow, 2004:268). The specific colors of the stamps, a 

subject of much specialization, can often be associated with the plate used, the year of 

production, or both. The year of production is deduced from dates found on postal usages and through the years agreed upon by specialists studying these stamps. However, 

almost no scientific work has been done in the area of inks, pigments, and the resulting 

colors. Nonetheless, speculation and hypotheses have abounded and have become part 

of the documented philatelic history of the stamp.

What follows is the history of what was believed concerning the colors and their 

origins for the subject stamp prior to the work recorded in this paper being done. This 

work was done to explore the elemental content of the stamps of the period with no 

preconceptions influencing the selection of the tools or the plan of the experiments or the 

possible outcomes. Nor was there any preconception about what would be discovered.

In Chase’s (1942:154–158) landmark book on the 3¢ stamp of the 1851–1857 

period, he described in some detail the various colors of the stamps by year. The sequence 

James A. Allen, 4608 Oakridge Drive, Midland, 

MI, 48640-1914, USA. Thomas Lera, National 

Postal Museum, Smithsonian Institution, P.O. 

Box 37012, MRC 570, Washington, D.C., 

20013-7012, USA. Correspondence: stampmole@

sbcglobal.net. Manuscript received 10 April 2013; 

accepted 26 April 2013.
7 2 • smithsonian contributions to history and technology

discussed by Chase, the one we will follow covering the first 

two years or so, begins with the orange-brown stamps, then 

the brownish-carmine stamps, followed by the dull red stamps. 

Chase then proceeds to hypothesize how these colors were compounded or created. Chase eliminated most dyes and lakes based 

on observed stamp colors, commonly known printing practices, 

and pigment availability at the time of the 1851 stamp production. This was a very logical and thoughtful assessment of the 

options for color generation of the time. The authors followed a 

similar approach in their analysis but with much more access to 

historical information. 

Chase then described experiments used to determine the 

primary pigment as Venetian red (an iron oxide–derived pigment, Fe2O3) augmented with vermilion (mercuric sulfide, HgS) 

to obtain a very rich, more orange color. Figure 1 illustrates an 

example of the orange-brown stamp used on a first-day cover 

dated 1 July 1851. 

He also commented the pigments used were, for the most 

part, resistant to sunlight. He speculated the stamp pigment was 

approximately 80% Venetian red and 20% vermilion based on 

experiments using color matching with selected contemporaneous pigments. He further commented on the pigment sensitivity to atmospheric sulfur dioxide. Occasionally, this pollutant 

caused darkening of the stamps, which he noted could be remedied by treatment with hydrogen peroxide, H2O2. Chase continued, saying the next “serious” color was brownish carmine. 

This is the most common color produced in 1852, although it 

first appeared in the late fall 1851. Chase went on to say it was 

probably a very good quality Venetian red without admixture of 

the vermilion as was done in the early orange-brown pigmented 

stamps (Chase, 1942:156). Indeed, today this color would approximate the artist color known as Venetian red. Figure 2 

shows the earliest documented example (22 October 1851) of 

the brownish-carmine color.

Chase continued, observing that soon after January 1853, 

another major color change occurred. The ink, he stated, “was 

somewhat suggestive of the original orange brown color, though 

the color is duller and impressions are never very clear” (Chase, 

1942:156). Figure 3 shows an example of the dull red–colored 

stamp from the author’s collection that was tested during the 

current research. Chase stated the pigment was Venetian red, 

though perhaps with less vermilion (Chase, 1942:156). This is 

his last mention of ink pigments for the stamps. 

Those pigments, Venetian red, or similar iron oxide–based 

pigments, with or without vermilion (mercuric sulfide, HgS), 

were deemed the component bases of the remainder of the colors 

of the series. Nothing was later added about ink composition 

versus perceived color versus years of use, except for a relatively 

standardized naming nomenclature per color per year range.

Post-1942 Color Explorations Until Now

Since the time of Chase’s book publication in 1942, almost 

no technical work, much less scientific work, has been performed 

on the 3¢ 1851–1861 stamps. The only notable exception has 

been very critical visual comparisons, categorizations, and 

Figure 1. Orange-brown color (Scott 10A) first-day cover, 1 July 1851. Courtesy of the author. 
number 57 • 7 3

naming of the 3¢ colors (Amonette, 1973; Beals, 1974; Amonette 

and Hulme, 2005). These works have become the basis of color 

standardization and naming in this area of specialization. The 

subject stamp was produced and used from July 1851 to the fall 

of 1861. As mentioned earlier, the 3¢ stamps were produced in 

many distinctive or slightly different colors, hues, and shades. 

However, it should be noted the term used to describe the color 

of this stamp by the Post Office Department was simply “red.” 

This fact is documented in correspondence from the Post Office 

Department to the stamp contractor, Toppan, Carpenter & Co. 

(Toppan, Carpenter & Co., 1851).

Color Differentiation and Naming

Color identification and matching have been done for the 

1851 3¢ stamps for over 70 years. Starting with Chase’s (1942) 

work, specialists have continued to study the colors. This has 

included Card (1964), Amonette (1973), Beals (1974), Amonette 

and Hulme (2005:103–109), and James Allen. 

Significant collections of these stamps, starting with those 

of Chase, have been retained and extended by today’s specialists. 

Through the years, additional stamps would be sent to all of 

the experts on this issue for identification. The colors were then 

agreed to by these experts, thus becoming a de facto standard. 

Standard color charts were then prepared using actual stamps. 

These charts can be used to perform color matching on unknown 

samples.

Ink Formulation in the Mid-­Nineteenth Century

During the period 1851–1861, based on actual practice, 

oil-based inks for banknotes, paper, and stamp production were 

fairly similar in composition and manufacture.1 The banknote 

inks were usually black and carbon based. Beyond the midnineteenth century, 1856 in the case of Toppan, Carpenter & 

Figure 2. Earliest known use, 22 October 1851, for brownish-carmine color (Scott 11A) (Plate 1 

late). Courtesy of the author.

Figure 3. Dull red color (Scott 11A) identified by Chase (1942). 

Courtesy of the author.
7 4 • smithsonian contributions to history and technology

Co., color began to be used more. The inks were composed of a 

liquid vehicle that was combined with the dry pigment portion 

of the ink.2 The liquid portion consisted primarily of linseed oil, 

often a blend of viscosities. It might also include a higher heat 

treated, slightly oxidized oil component called a varnish to modify viscosity and aid in adhesion. Finally, other ingredients were 

often included: a drying agent, a very volatile hydrocarbon to 

facilitate mixing and wetting of the pigments, a wax to modify 

flow properties, and a few other proprietary ingredients. The 

actual solvent recipes are rarely found or are nonexistent. Pigment recipes for early stamps are rare and proprietary. That was 

all part of the craft at the time. Vehicle properties were tailored 

to the needs of the final ink properties desired and the specific 

incorporated solids. Attention was paid to the ability to mix the 

ground pigments thoroughly into the vehicle. These were, by 

nature, complex mixtures that required recipes and significant 

knowledge and skill of the ink maker. Inks for the banknotes 

were compounded “in house” most of the time and were modified as needed during production. Carbon-based black inks 

could be purchased premixed depending on the nature of the 

ink and printing desired. Colored inks, however, often required 

mixing on site for technical reasons. The ink recipe formulations, including the pigments used, were often proprietary in 

nature. 

Opaque, semiopaque, and translucent inks were engineered 

to give rise to dried films of particular characteristics such as 

opacity, carefully designed hues and shades, reflectivity, adhesion, drying characteristics, and long-term stability, all the while 

with attention paid to cost. Many pigments or inks in this period 

were relatively expensive. Solid ingredients such as extenders 

were used essentially to produce more of the ink through basic 

dilution while not sacrificing the body of the ink or altering the 

color any more than necessary. Other solids might be added to 

change the tint of the final product or were added to maintain 

the effect of translucency because of selected refractive or reflective properties. Still other pigments were added to increase 

opacity. All pigments had some of these characteristics to effect 

change and had to be carefully selected and formulated to get the 

desired effects. A good summary of many of the elements and 

pitfalls of ink production, albeit derived from a later banknote 

period but that are nevertheless applicable to the 1851 decade, 

has been written by Sayers (2009). 

Most of the pigments of this period were either ground naturally occurring minerals or chemically prepared, precipitated 

compounds. Ground, mined pigments were already declining in 

relative usage volumes compared to the growing uses of chemically synthesized versions. Chemically prepared pigments appeared by the 1820s, and by the late 1860s significantly more 

were introduced. This was facilitated by the growth of the German chemical industry for producing chemical dyestuffs. For all 

practical purposes, only a few natural dyestuffs were available 

during the time period considered and were not used in the formulation of the ink for these stamps. This will be discussed later 

in the pigment determination section.

EXPERIMENTAL SETUP

The experimental setup includes both the selection of stamps 

for analysis and the selection of analytical hardware. These are 

described in the following sections.

Sample Selection

This research was limited to 3¢ 1851 stamps issued during 

the first 24 months of usage. The specific stamps selected for 

testing represent the five important colors of this early period. 

Those colors are orange brown, the experimental orange-brown 

color with the mid-1852 color being a variant, brownish carmine, the 1852 claret, and dull red. They were selected based 

on standards discussed in the “Color Differentiation and Naming” section above. The reader should consult the references for 

more information. Colorimetric and XRF analyses were then 

performed on each test sample as described in the following section. The elemental compositions of the ink were then used to 

deduce the pigments that were used in the ink formulation. This 

inference was drawn by considering historically used pigments, 

their commercial availability, and their color characteristics. For 

this paper, 11 stamps were selected to illustrate the experimental 

procedures and results interpretation. For identification, these 

were labeled Sample A to Sample L (no Sample I). Results of the 

analyses of these samples are given in subsequent sections.

Hardware Selected for Performing the Analyses

As introduced above, two analytical devices were selected for 

this research. The first was the Video Spectral Comparator (VSC 

6000),3 (Foster + Freeman, Ltd., 2011), and the second was the 

Bruker Handheld Tracer III-SD X-Ray Fluorescence Analyzer.4

Both of these devices, located at the Smithsonian National Postal 

Museum in Washington, D.C., are described very briefly below.

The Video Spectral Comparator (VSC 6000)

The VSC 6000 is an analytical device that can perform many 

different forensic analyses on paper documents. It has a number 

of functions that are ideally suited for the analysis of philatelic 

material. The capability used for this research was to determine 

the reflectivity of sample stamps under light with wavelengths 

from 400 to 1,000 nm. This range includes visible light and nearinfrared and near-ultraviolet wavelengths. More important, the 

VSC 6000 can provide quantitative measures of colors, or colorimetry analysis, based on the CIE color standards.5

Bruker Handheld Tracer III-SD X-Ray 

Fluorescence Analyzer

For elemental analysis of the ink on the subject stamps, a 

Tracer III-SD X-ray fluorescence analyzer was used. This spectroscopic device uses X-rays to excite electrons in the atoms in 
number 57 • 7 5

a specimen to be analyzed. These atoms then emit photons that 

can be counted. Each chemical element emits photons at different energy levels. The number of counts for each energy level, 

measured over a given sampling period, indicates the amount of 

various elements present in a sample. Figure 4 illustrates a typical spectrograph that results from the XRF analysis. Software 

that is part of the testing device produces the spectrographs and 

also helps identify the specific elements present.

It is also possible to describe elemental content by the number of counts for each element. This method will be used subsequently in this paper.

EXPERIMENTAL RESULTS

As noted above, two types of analysis were performed on each 

of the sample stamps. The first was an analysis of color using the 

VSC 6000, and the second was an analysis of chemical elements 

using the Bruker XRF. The results are presented in this section. 

Color Analysis

The VSC 6000 was used to measure the reflectivity of all of 

the sample stamps. Figure 5 illustrates the range of stamp colors 

that were obtained by this testing. While five major colors were 

highlighted for testing for elemental analysis, a much larger sample was used merely to explore the range of color variations as detected by the VSC 6000 colorimeter. The 33 points correspond to 

measurements at three different locations on each of 11 different 

stamps selected for color variations, which included heavily inked 

areas and lightly inked areas that would include more color influence caused by the paper. Figure 5 also shows a small ellipse. This 

is called a MacAdam ellipse. It represents an estimate of a discernible range of colors that an individual perceives as being the same 

Figure 4. Typical X-ray fluorescence spectrograph, illustrating portion of stamp ink for three different samples of Scott 10A. The white oval 

on the inset stamp is the approximate sample size. Courtesy of the author.
7 6 • smithsonian contributions to history and technology

(MacAdam, 1942; Wyszecki and Stiles, 2000:308; Herendeen et 

al., 2011:108). The size of the color gamut of the measured stamps 

is many times the size of the MacAdam ellipse. 

Thus, there are definitely many different, and discernible, 

colors of the stamps examined. Figure 6 shows the location 

of the measured colors on the CIE uniform chromaticity scale 

(Billmeyer and Saltzman, 1981, chapter 2). Visual analysis of 

the stamps and their resulting positions logically followed the 

“warmth or coolness” expected from the color gamut in Figure 6. Future work with this technology will explore the value 

of these analyses for evaluating standard colors. Overall, these 

stamps were classified as “red” when specified by the Post Office Department back in 1851, and certainly they fall into that 

part of the spectrum as shown in Figure 6, with a bias towards 

“brown or orange” as they are observed today.

In simple terms, the plot in Figure 6 also shows, in the “plus 

square” near the top, the location of the colors of the 3¢ 1851 

stamps tested under the current research on a full gamut of perceivable colors. As noted, this research restricted the detailed 

analysis and discussion to the first 24 months or so of issuance, 

specifically addressing the colors mentioned previously that were 

identified by Chase and the other students of the 1851 issue.

XRF Analysis

When using XRF, the X-rays generally penetrate the whole 

stamp. As a result, the elemental composition of the paper is also 

being measured. This research performed testing to correct for 

any errors that this might introduce. All samples were irradiated 

for 180 seconds, and the resulting photon counts were recorded. 

Basically, the stamp is irradiated with measurements taken front 

and back on inked and very lightly inked or uninked portions of 

the stamp. By comparing the photon readings between the front 

and back, with a check when possible on the marginal paper that 

is not inked, one can ascertain the base number of photon emissions coming from elements in the paper. To correct for these 

effects, one can subtract the resultant photon measurements of 

the back from the photon measurements from the front. A titanium filter (called a blue filter) was used to measure the reflected 

photons from Mg, Al, Si, P, Cl, S, K, Ca, V, Cr, and Fe and any L 

and M lines for the elements that fall between 1.2 and 6.5 keV. 

All photons beyond 6.5 keV were filtered out.

Accounting for Paper Chemistry

During stamp production, sheets were routinely stacked in 

piles to complete the drying and curing process or for storage 

prior to gum application. As a result, the backs of the stamps 

may have pigment traces. While these are actually contaminants, 

and perhaps not visible, they could still be sufficient to be detected by XRF. Such photon readings can be mistaken for paper 

elemental content. However, the counts here are fairly low relative to those measured on the front of the stamp. Thus, they have 

no significant impact on the conclusions.

The Pigments

Likely pigments and their properties were determined by 

studying various key reference texts (Eastaugh et al., 2008; Higgitt et al., 2005) and then selecting possible pigments based on 

Figure 5. Chromaticity plot of 1851 3¢ stamps.

Figure 6. Location of 3¢ stamp colors in full 1976 CIE color 

gamut.
number 57 • 7 7

elemental content. Those candidates were then researched further based on their relevant color and probability of use during 

the 1851–1861 period.2 Pigment properties were also assessed as 

to their chemical and light stability. Thus, obvious fugitive colors 

that are very sensitive to environmental factors were eliminated. 

The likely pigments are mineral based and all were also available 

chemically produced at the time. While a few of the available 

pigments arose from mining, these were generally of lesser quality. In either case, XRF identifies the important elements in the 

pigment and results in the same basic conclusions. Another important observation is the analyst can glean additional valuable 

information about possible pigments by noting which elements 

are not present in the XRF scans.

The commercially available dyes in the general color family 

of this particular period used to any significant degree were natural products. These included, for example, brazilwood, logwood, 

cochineal, and madder. Pigments derived from these products 

had a number of problems, including the following:

• They could be fugitive;

• They could become unstable in the presence of other pigments;

• They could bleed into the other pigments or the paper; 

and

• They were the wrong color match for the finished stamps, 

at least when viewed in the current era 155 years after 

the stamps were printed.

Additionally, the “laking” processes at the time utilized primary flocculation of the colors on amorphous aluminum-based 

substrates with calcium salts (Ellis, 1940:158–159). Aluminum 

is one of the most widespread elements in the universe and is 

expected to appear in all elemental analyses of mixed products. 

Therefore, the presence of more than a trace of aluminum would 

be a requirement for most of the red lakes. This result was not 

found for the samples tested. Calcium salts, which are present in 

nearly all lake pigments, were present in all the pigment portions 

of the stamps tested. However, calcium could be expected to be 

present in the paper as well as a consequence of the preparation 

water (but only at very low levels). Water sources for paper production during this period were selected for overall low mineral 

content. Calcium salts are likely candidates as a filler or colorant 

in any paper, usually in the form of calcium carbonate (CaCO3).

The Orange-Brown Shades

Figure 7 shows a range of orange-brown stamps used in 

the early period of the 1851 3¢ issuance. Dated orange-browncolored stamps range from 1 July 1851 to mid-1852 or a little 

later, but few orange-brown stamps are found after March 1852. 

They originated primarily from five plates. Table 1 presents the 

XRF results, giving photon counts for various elements. We observed that all the orange-brown stamps of the 1851 period that 

were sampled contain primarily iron as the principal elemental 

colorant source. Iron oxide (Fe2O3) is the clear choice from the 

historical pigment considerations. This pigment has what is called 

a high extinction coefficient. This means it imparts color very effectively at low volume or weight because it is intense and saturated as determined by eye or machine. The artist color and name 

and ink color today would be similar to that named burnt sienna. 

At the time of the 1851 stamp, Venetian red was the most 

common reddish brown earth pigment. It varied in shade and 

hue depending upon the manufacturer and whether it was mined 

from the earth as hematite or chemically produced. Today Venetian red as a named pigment is much redder and darker. It is an 

earth pigment, and while it was still mined in the 1850s, it was 

becoming widely available as a synthetic, having been manufactured chemically for over 50 years at the time the 3¢ 1851 was 

produced. Chemically manufactured pigments were preferred 

by the 1850s and earlier because of their typical higher quality, 

consistency, and minimum contaminates. By 1850, all calcium 

and lead salts that might be used in pigments or extenders were 

chemically prepared and relatively pure. The red lead chemical 

Figure 7. Representative orange-brown stamps used for testing. Courtesy of the author.
7 8 • smithsonian contributions to history and technology

process, for example, had been around for hundreds of years. 

The calcium salts used were all white and uniform. Any iron 

oxide variations due to sourcing, whether mined or chemically 

prepared, would then require more fillers and extenders in an 

attempt to achieve consistent shades and hues. 

Table 1 shows that one of the inks contained barium (Ba). 

The sample shown was not a single occurrence. Barium sulfate 

(BaSO4) is slightly opaque and white in color and was commonly 

used as an extender to dilute the more expensive pigment in the 

ink. It was commonly synthetic but could be mined as the mineral 

barite. No barium pigment at the time was colored other than 

white except for barium chromate (BaCrO4), and the samples 

tested did not show chromium. Given the small amount of sulfur 

present, this should be attributed to the barium sulfate component, which is likewise small, and the calcium salt would likely be 

predominantly calcium carbonate. Calcium carbonate (CaCO3) 

and calcium sulfate (CaSO4) were and are both used to extend 

inks and to tint them because they are white in color. However, 

they have low refractive indexes and are not very efficient in tinting or achieving opacity, thus leaving an ink more translucent. 

Simple calcium salts such as the ones mentioned are all white 

but less so when dispersed in linseed oil. Varieties and ranges of 

particle size and oil take-up of the extenders were used to affect 

handling characteristics and final refractive indices of the ink. 

The Experimental Orange Brown

Figure 8 shows samples of the experimental orange-brown 

color used for testing. Table 2 shows the elemental content of 

these samples. This color was suddenly introduced in early October 1851, for reasons still unknown. It is suspected to be related 

to the issues surrounding the original orange-brown pigment and 

is the subject of ongoing research.

Sometime after Chase’s (1942) publication, many students 

began to realize in fact this was a significant color variety that 

was in effect for about five months, even if it was a relatively 

Table 1. Chemical elements in orange-brown stamps, photon counts at 180 seconds, all corrected for paper content.

Calcium Iron Lead Sulfur (S) Other

Stamp (Ca) (Fe) (Pb)a (blue filter) elements

Sample A, position 59L1 early; yellowish orange brown; 54,000 96,000 99,000 4,400 0 Mercury (Hg)a

earliest color, 1851

Sample B, position 7R1 early; orange brown; 170,000 360,000 332,000 6,500 0 Mercury (Hg)a

first two weeks of production, 1851

Sample C, position 92R1i; orange brown; 28 Nov 1851 50,000 101,000 80,000 4,500 0 Mercury (Hg)a

Sample D, position 91R2 early; orange brown; early 1852 88,000 310,000 152,000 6,500 0 Mercury (Hg)a

 8,000 Barium (Ba)a

aResults from the L1 energy level.

Figure 8. Representative experimental orange-brown stamps used for testing. Courtesy of the author.
number 57 • 7 9

scarce color change in the broad scheme of color groups based 

on populations. As a result of this research, it has been determined that the experimental orange brown was not just a variation of orange brown but was in fact foreshadowing a major 

change in color schemes and pigment chemistry. 

It is noted some of these experimental orange-brown stamps 

contain barium (Ba). One sample contained iron (Fe), which 

could be a cross-contamination from the orange-brown ink that 

was still in production at the time. That sample, Sample H, is 

what is classed as a mid-1852 orange brown, which is duller 

in shade and does not fit into other color classifications. The 

iron-based pigment continued to be used on select plates, or at 

least stamps appearing on dated letters, well into 1852, dropping 

quickly in numbers into the year, being replaced by several leadbased pigments and colors.

Later Shades

Table 3 shows the XRF results for three stamps printed after 

the experimental orange brown introduction, as shown in Figure 

9. The results show that the move to lead-based pigments continued. The brownish carmine of 1852, which is considered the primary color for the year based on populations (Amonette, 1973; 

Amonette and Hulme, 2005), and the 1852 claret, a lesser color 

variety introduced in late 1851 and discontinued in early 1852, 

both utilized primary lead-based systems with no significant iron 

(Fe) present in the inks. The iron (Fe) present in the brownishcarmine sample is likely from the blue cancel common to the 

period, iron ferrocyanide (Prussian blue). Sulfur is also present 

and likely attributable to the filler calcium sulfate, CaSO4. Noteworthy is the fact that Sample L, the characteristic “dull red” 

color of late 1852 extending well through 1853 and beyond, 

contains not only sulfur (S) but also chromium (Cr). This was the 

first sample detected to contain chromium in these early years. 

The likely source is lead chromate (PbCrO4), which is normally 

yellow, but orange and red varieties also exist. Again, red lead is 

a possible candidate for the primary “red” color, augmented by 

whites and possible yellow or orange. It is highly unlikely that 

the initial color mixed was quite this dull based on the known 

color chemistries. It should be noted that no mercury (Hg) is 

Table 2. Chemical elements in experimental orange-brown stamps, photon counts at 180 seconds, all corrected for paper content.

Calcium Iron Lead Sulfur (S) Other

Stamp (Ca) (Fe) (Pb)a (blue filter) elements

Sample E, experimental orange brown; 8 Oct 1851, 260,000 0 650,000 12,000 0 Mercury (Hg)a

second earliest date

Sample F, 1852 brownish carmine, position 4R3; 114,000 0 462,000 9,200 0 Mercury (Hg)a

28 April 1852 5,000 Barium (Ba)a

Sample G, 1852 claret; 2 Feb 1852 110,000 0 420,000 12,000 0 Mercury (Hg)a

 5,000 Barium (Ba)a

Sample H, early, dull red (unused) 90,000 4,000b 150,000 8,500 0 Mercury (Hg)a

aResults from the L1 energy level.

bContamination suspected from orange-brown pigment.

Table 3. Chemical elements in later shades of stamps, photon counts at 180 seconds, all corrected for paper content.

Calcium Iron Lead Sulfur (S) Other

Stamp (Ca) (Fe) (Pb)a (blue filter) elements

Sample J, 1852 brownish carmine, position 4R3; 138,000 <10,000b 353,000 6,600 0 mercury (Hg)a

28 April 1852

Sample K, 1852 claret; 2 Feb 1852 127,000 0 397,000 7,700 0 mercury (Hg)a

Sample L, early, dull red (unused) 190,000 0 300,000 10,000 0 mercury (Hg)a

 15,000 chromium (Cr)c

aResults from the L1 energy level.

bContamination suspected from orange-brown pigment.

cEarliest historical evidence of appearance of chromium in these pigments.
8 0 • smithsonian contributions to history and technology

present in any of the samples in the data tables. Sampling stamps 

across the entire 10 years has revealed no mercuric sulfide presence. The lack of the presence of mercury indicated the lack of 

the presence of the pigment vermilion (HgS), which had been 

hypothesized 80 years earlier and is repeated often in the philatelic literature. However, the practitioner should also note that 

vermilion can be present in cancellation inks and must be taken 

into account with any element measurements. 

CONCLUSIONS

There are three groups of conclusions for this study: the use 

of the analytical equipment, the results of the pigment and color 

analyses, and new discoveries made during the research. These 

are described in the following sections.

Analytical Equipment

There are three major conclusions relating to the experimental hardware used for this study. They are presented below.

• The Video Spectral Comparator (VSC 6000) has proven 

capable of determining quantitative color measurements 

for the 1851 color shades in line with human visualizations in a limited but meaningful way.

• X-ray fluorescence spectroscopy (XRF) has been shown 

to be a useful tool for elemental analysis, which helps 

to define pigment composition differences for the United 

States 1851 3¢ stamps.

• XRF is particularly effective in proving what elements 

and, by inference, which pigment is not present in a 

stamp ink.

• When performing experimental measurements, care must 

be exercised in determining, and correcting for, elements 

within the paper of the stamp as well as other inks on the 

stamp arising from cancellations or markings.

Pigments

• The primary pigment colorant for the initial 1851 

orange-brown (Scott USA numbers 10 and 10A) (Scott 

Publishing Co., 2012) stamp appears to be iron based, 

probably iron oxide in natural or man-made form. It is 

listed as primary because of its dominance.

• The secondary pigment(s) used to augment the 1851 

orange-brown pigment is lead based and is likely red lead 

(Pb3O4). It is a major component of the ink. It is listed as 

secondary because of less coloring capacity or remaining 

influence compared to the iron oxide.

• Several extenders and possible tinting agents seem to 

have been used in the first 24 months, notably BaSO4 and 

CaCO3, with minor impurities not assignable to significant pigments of the time.

• The brownish-carmine stamp pigments of the early 

period, fall 1851, were also a primarily lead based system, likely red lead. Clear evidence of dyes or dye lakes 

(such as significant aluminum content) is not readily apparent. Assuming the lake colors are visible at all, such 

colors were derived from dyes available at the time, and 

while they are inconsistent with the hues achieved in the 

finished stamps as they are viewed today, they cannot be 

eliminated from consideration. 

• No iron, in any form, was found in the brownish-carmine 

stamp pigments of the early period. 

• A base level of iron was always found in these earlier 

stamp papers. 

• The dull red of the late 1852 and early 1853 period is 

also predominantly lead based with a variety of extenders and diluents, varying in proportions.

Figure 9. Representative stamps of shades in postexperimental (later shades) 

orange-brown period used for testing. Courtesy of the author.
number 57 • 8 1

New Discoveries

• The experimental orange-brown color represents a major 

pigment transition heretofore not recognized other than 

by the appearance of an odd color. The pigments for the 

experimental orange-brown stamps are lead based and 

not iron oxide based like the original and associated 

orange-brown stamps, contrary to popular understanding. Iron content is basically nonexistent in the pigmentation of these stamps.

• Given the elemental analysis of the stamps and their 

dates of use, the move to the primarily lead based system 

and away from the iron oxide–based system used for the 

initial orange-brown stamps must have likely been made 

in mid-September 1851 or earlier.

• While cadmium pigments were coming onto the colorant 

scene during this period, no cadmium was found in the pigments, even at trace levels, over the 10-year span studied.

• Contrary to historical accounts and speculation, no vermilion or mercuric sulfide sources have been detected in 

the 1851 3¢ series of stamp color varieties in the first 24 

months of issuance of the subject stamps tested. Vermilion is not the “orange” color modifier for the Venetian 

red (iron oxide) as has been stated and often repeated 

over the last 80 years in the literature.

NOTES

1. While the two cited references (Eastaugh et al., 2008; Higgitt et al., 2005) 

are most useful, there are no single reference sources that adequately cover the pigments, and their chemical and physical properties, for this period. More than 50 

artist, museum, pigment, and historical books, articles, and Web sites were used. 

Those appearing to provide consistent information were considered reliable. The 

most difficult data to find was a description of which pigments were used during the 

period of study and when they may have been introduced. An especially useful Web 

site that provides much basic information is http://www.webexhibits.org/pigments/, 

titled Pigments Through the Ages (accessed 1 March 2013).

2. In the ink industry, the term “vehicle” is traditionally used for the liquid 

material holding and carrying the pigment and providing good workability on the 

press. Vehicles for intaglio inks may include oils, solvents, binders, and the like. 

Historically, linseed oil was the primary vehicle for mid-nineteenth century inks.

3. The Video Spectral Comparator 6000 is a spectrophotometric device used 

primarily for forensic document examination. It is manufactured by Foster + Freeman, Ltd. of the United Kingdom and United States. For more information, see 

http://www.fosterfreeman.com (accessed 1 October 2012).

4. The Bruker Tracer III-SD X-Ray Fluorescence Analyzer is a portable X-ray 

fluorescence spectrometer that allows unknown samples to be analyzed for their 

elemental composition. For more details, see http://www.bruker-axs.com/handheld

-xrf-analyzers.html (accessed 1 October 2012).

5. CIE, the Commission Internationale de l’Éclairage (International Commission on Illumination), formed in 1913, is the international organization that 

develops standards for everything having to do with light and color. They have 

had a number of color standards through the decades used for color matching. 

For more information, visit their Web site at http://www.cie.co.at/main/ (accessed 

1 October 2012).

REFERENCES

Amonette, W. F. 1973. Color Study of the Three-Cent Stamp of the United States 

1851–57 Issue. Chronicle of the U.S. Postal Issues, 25(2):85–91.

Amonette, W. F., and W. Hulme. 2005. Color Study of the 3¢ Stamp of the United 

States 1851–1857 Issue: An Update. Chronicle of the U.S. Postal Issues, 

57(2):103–109.

Beals, D., III. 1974. Colors of the Three Cent 1857–61 Perforated Type II Stamps 

(54 and 55). Chronicle of the U.S. Postal Issues, 26(1):14–17.

Billmeyer, F. W., Jr., and M. Saltzman. 1981. Principals of Color Technology. 2nd 

ed. New York: Wiley-Interscience.

Card, D. A. 1964. Some Thought about the Colors of the 3¢ 1851 (S1 and S2) 

Stamp. Chronicle of the U.S. Postal Issues. 17(1):6–10.

Chase, C. 1942. The 3¢ Stamp of the United States 1851–1857 Issue, Revised.

Lawrence, Mass.: Quarterman Publications.

Eastaugh, N., V. Walsh, T. Chaplin, and R. Siddall. 2008. Pigment Compendium, 

A Dictionary and Optical Microscopy of Historical Pigments. Amsterdam: 

Elsevier.

Ellis, C. 1940. Printing Inks, Their Chemistry, and Technology. New York: Reinhold Publishing Corporation. 

Foster + Freeman, Ltd. 2011. VSC 6000. Video Spectral Comparator Software 

Manual. Worcestershire: Foster + Freeman.

Granzow, G. W. 2004. The Plates of the 1851–1857 3¢ Stamps of the United States, 

Part III: Perforated Stamp Plates of 1857–60. Chronicle of the U.S. Postal 

Issues. 56(4):263–268.

Herendeen, D. L., J. A. Allen, and T. Lera. 2011. Philatelic Shade Discrimination 

Based on Measured Colour. London Philatelist, 120:105–117.

Higgitt, C., M. Spring, and D. Saunders. 2005. Pigment-Medium Interactions in 

Oil Paint Films Containing Lead-Based Pigment. WAAC Newsletter, 27(2): 

12–16.

MacAdam, D. 1942.Visual Sensitivities to Color Differences in Daylight. Journal 

of the Optical Society of America, 5:247–274. http://dx.doi.org/10.1364

/JOSA.32.000247. 

Sayers, G. 2009. Production Plate Varieties and the Nature of Opaque Inks, with 

Notes on the Post Office “Scummy” Printings. Chronicle of the U.S. Postal 

Issues, 61(4):310–325.

Scott Publishing Co. 2012.2012 Specialized Catalogue of United States Stamps. 

Sidney, Ohio: Scott Publishing.

Toppan, Carpenter, Casilear, & Co. 1851. Correspondence, #169, June 10, 1851, 

as Transcribed by Wilson Hulme. Washington, D.C.: Smithsonian National 

Postal Museum.

Wyszecki, G., and W. S. Stiles. 2000. Color Science. New York: Wiley-Interscience.

Analysis of Postage Stamps by Proton-Induced 

X-Ray Emission Spectrometry

Thomas E. Gill

ABSTRACT. Subtle variations in ink color and paper of postage stamps can affect their 

value and desirability to collectors and investors. Proton-induced X-ray emission spectrometry (PIXE) is a generally nondestructive forensic analysis tool that reveals the concentrations of chemical elements in a sample. PIXE has been used for more than 30 years, 

sometimes in conjunction with other analytical methods, to differentiate philatelic printing techniques; to quantify differences between different shades, varieties, and reprints of 

stamps; and to separate genuine stamps from forgeries. This paper reviews the history of 

philatelic paper and ink analysis by PIXE through a focus on case studies from the 1980s 

to the present. For example, PIXE has been used to show distinct chemical signatures between genuine stamps from China, Czechoslovakia, Eastern Silesia, South Africa, SouthWest Africa, and Taiwan and forgeries thereof. PIXE analysis showed how variations in 

ink chemistry control color shades of stamps from Mexico and reveal the origin (country 

of printing) of Iranian stamps, suggesting early (pre-twentieth century) utilization of organic inks on European-printed stamps from both nations. The technique was utilized to 

determine variations in paper types on stamps from China and Taiwan and how original 

People’s Republic of China stamps from the early 1950s can be separated from modern 

reprints. The paper concludes with a PIXE investigation of Mexico’s 1895–1898 “Mulitas” stamps. The analysis reveals that unlike previous Mexican issues, the Mulitas were 

printed with organic-based inks on largely clay-free papers. Differing amounts and/or 

formulations of metal (zinc, lead, and titanium) oxide whiteners apparently controlled 

the present-day color shade of the stamps, either directly or indirectly, with bluish inks 

having relatively more zinc and lead and greenish inks having relatively more titanium.

Introduction

Since their introduction in 1840, postage stamps have been acquired as collectibles 

and investments and studied to reveal information on the history of printing and the 

chemical and material properties of papers and inks. Potentially subtle variations in ink 

and/or paper of stamps with otherwise identical designs may affect their value and desirability to philatelists and investors or reveal them to be forgeries or reprints. Because of 

its ability to nondestructively reveal elemental compositions, proton-induced X-ray emission spectrometry (PIXE) has long been an applicable technique for analysis of a variety 

of historical inks and papers(Cahill et al., 1981; Johanson, 1989; Demortier, 1991; Hassanzadeh et al., 1999) and has been used for analysis of postage stamps from the technique’s early days to the present (e.g., Cahill et al., 1981; Malmqvist, 1986; Almquist, 

1985, 1986, 1988; Johanson et al., 1986; Hall and Lee, 1990; Johanson, 1992; Cheng 

et al., 1996, 1998; Pillay, 2000; Gill, 2007; Oliaiy et al., 2009; Voltr and Nejedly, 2012). 

Thomas E. Gill, Department of Geological Sciences, University of Texas at El Paso, 500 West 

University Avenue, El Paso, Texas, 79968, USA. 

Correspondence: tegill@utep.edu. Manuscript received 10 April 2013; accepted 26 April 2013.
8 4 • smithsonian contributions to history and technology

PROTON-INDUCED X-RAY 

EMISSION SPECTROMETRY

Proton-induced X-ray emission spectrometry was developed in the 1970s as a multielemental analysis technique that 

is generally nondestructive; requires minimal or no sample prepreparation; and is quantitative, fast, and sensitive (Pillay, 2000). 

It is conceptually similar to X-ray fluorescence spectrometry 

(XRF), which has also been used for analysis of stamps (Preiss 

and Robie, 1982; Cesareo and Brunetti, 2008; Jelovica Badovinac et al., 2010), but with PIXE a beam of protons, generally 

with energy of millions of electron volts (MeV), is used to bombard a sample. A particle accelerator, usually a Van de Graff 

accelerator, cyclotron, or similar machine, is used to create the 

proton beam; thus, PIXE facilities generally exist only at specialized academic or national nuclear laboratories (Johanson, 1992) 

and are less ubiquitous and much more costly than XRF. The 

high-energy proton beam ionizes some of the atoms in the sample. Some of the electrons in the inner shells orbiting the sample’s 

atomic nuclei are knocked away, creating a “hole.” In response, 

other electrons “drop down” from outer orbitals of the atom 

to “fill the hole” and take the place of the ejected electrons. In 

the process, X-rays with a constant and unique energy for each 

such transition (characteristic X-rays) will be emitted (Johanson, 

1989). Each chemical element will typically have several unique, 

characteristic X-ray emission energies. This discovery, made by 

Moseley 100 years ago, led him to suggest that emitted X-ray 

spectra could be used for chemical analysis (Moseley, 1913). 

These X-rays are measured by a detector and converted to electronic signals, and software is used to calculate the concentrations of the individual elements within the analyzed part of the 

sample from the number of X-rays detected with each characteristic energy. The higher energy of the proton beam used in PIXE, 

as compared to the X-ray beam in XRF or electron beam from 

an electron microprobe, allows for higher sensitivity than these 

other techniques, detecting smaller concentrations of a material’s 

constituent elements more quickly.

Although all detectable elements are quantified simultaneously, the PIXE technique allows detection only of elements sodium and heavier, so the lightest elements such as carbon and 

oxygen cannot be analyzed directly by PIXE. PIXE successfully 

detects a number of relatively light elements such as aluminum 

(used as a sizing agent for some philatelic papers) (Lera et al., 

this volume) and magnesium (also found in some philatelic papers) (Almquist, 1988) not determined by X-ray fluorescence. 

The technique works best for quantifying elements with atomic 

numbers between 20 and 30 (Johanson, 1992), including calcium and the “transition metals” such as iron and zinc (common 

components of printing inks and papers), where concentrations 

as low as a part per million or less can be routinely detected 

(Johanson, 1992). Samples that are thin and flat, such as postage stamps, provide ideal surfaces to be analyzed by PIXE. The 

actual detection limit (minimum concentration of an element detectable in the sample) will depend on the energy of the beam and 

the length of time the sample is exposed to the beam. Samples 

may be analyzed in a vacuum; in a chamber filled with helium, 

argon, or another gas; or in air (the “external beam” technique 

often used for philatelic applications [Almquist, 1985; Hall and 

Lee, 1990; Voltr and Nejedly, 2012]). The proton beam generally 

penetrates only an ultrathin layer on the surface of the sample. It 

will not pass through the paper of a postage stamp or envelope, 

thus revealing the composition of the printing ink or, when the 

beam is placed on a portion of the stamp clear of the design, the 

paper. The size of the beam determines which part of the sample 

is analyzed at any given moment. Most reported philatelic analyses have been of spots on the stamp several millimeters in diameter (“proton milliprobe”), although the beam can be focused 

down to pinpoint tiny areas on the order of a micrometer in size 

(“proton microprobe”) or moved across the sample to provide 

its overall composition. X-ray spectrometric techniques can also 

often be useful to determine what elements are not present in an 

ink or paper (beyond a minimum concentration), in addition to 

what elements are present (Allen and Lera, this volume). This is 

especially true for PIXE, with its relatively low minimum detection limits for many elements.

A potential disadvantage of PIXE is that it is purely an elemental analysis technique. PIXE cannot reveal the crystal structure or molecular species in which an element resides, which has 

led to controversies in its application for analysis of historical 

documents such as the titanium contained in the Vinland map 

(Skelton et al., 1995).1 With regard to the detection of fakes and 

forgeries, PIXE data can only show that the elemental concentrations and ratios are consistent with a known ink or paper, not 

always conclusively proving the (in)authenticity of a given item. 

PIXE relies on proton beams of high energy, typically in the millions of electron volts. This is an advantage in that it can detect 

lower concentrations of elements than other techniques such as 

X-ray fluorescence. However, it also represents a disadvantage in 

that prolonged exposure to the beam, longer than a few minutes, 

could burn or otherwise damage fragile materials such as paper 

(Cahill et al., 1986; Hall and Lee, 1990; Xeng et al., 1990; Demortier, 1991; Sánchez, 2006). Hall and Lee (1990) sandwiched 

the stamps they analyzed between thin layers of Kapton film and 

still observed some damage after five minutes of exposure to the 

proton beam. Voltr and Nejedly (2012) examined stamps by 

PIXE at reduced pressure in an argon atmosphere to decrease the 

potential radiation damage compared to analysis in a vacuum, 

while still allowing a quantitative analysis. When used carefully, 

however, PIXE is a nondestructive method of testing. The experiences of multiple investigations (as described throughout this 

paper) show that a thorough and ample PIXE analysis should be 

obtained within a few minutes of irradiation, which would not 

risk damage to the stamp. 

Although PIXE has been used most widely in materials science, environmental studies, and biological and geological investigations, it was recognized early on as a powerful tool for 

historic and forensic analyses of inks and papers (Cahill et al., 

1981; Thompson, 1983; Kusko, 1988), especially after it was 
number 57 • 8 5

used to reveal the printing methods and materials of the “Gutenberg Bible” (Schwab et al., 1983). Since then, reviews of this 

technique inevitably mention its application for analysis of historical printed documents (Johanson, 1989, 1992; Demortier, 

1991; Pillay, 2000; Vijayan et al., 2003; Vodopivec et al., 2005).

PHILATELIC APPLICATIOnS OF PIXE: 

A REVIEW

The first published report on the application of PIXE in 

philately was written by the late chemist and philatelist Herbert J. Almquist, appearing in the American Philatelist in 1985 

(Almquist, 1985). Almquist worked with physicists and document experts at the Crocker Nuclear Laboratory2 of the University of California-Davis, utilizing PIXE to analyze variations in 

color from blue-green to dull green of ledger lines on the paper of 

the Mexican “Large Numerals” stamps printed in 1887 (Scott3

195–211) (Figure 1).

No significant variations were found in the elemental chemistry of the different colored lines, and Almquist (1985:242) concluded “the grey-green color is derived from the turquoise-green 

by aging and sulfurization over a period of many years.” The 

PIXE analyses did, however, shed light on the compositions of 

the paper and the ledger line ink, suggesting that clay and a calcium compound were added to the paper and that the ink was 

an “iron blue” compound with zinc oxide added as a whitener. 

Additional analyses of the papers, as well as the ink used to 

print the Mexico 1-centavo green stamp (Scott 201) (Figure 2), 

were reported a year later in Mexicana, the quarterly journal of 

the Mexico-Elmhurst Philatelic Society International (Almquist, 

1986). Almquist (1986:207) concluded that “the amounts of clay 

corresponding to these elements could be several percents of the 

paper,” that the green ink and the green lines on the paper were 

derived from different materials, that the green color of the ink 

could have been derived in part from green chromic oxide, and 

that zinc and lead oxides were used as whiteners in the inks. A 

final set of PIXE analyses reported by Almquist (1988) examined 

the compositions of the paper used for the “Numerals” issue and 

three other watermarked papers used for contemporary Mexican 

stamps (Scott Mexico watermark numbers 152–154). The presence of relatively high amounts of magnesium, silicon, and aluminum in the Numerals paper, but not the watermarked papers, 

suggested to Almquist that the ledger-lined papers of the Numerals were grass based with clay fillers, while the watermarked 

papers were derived from wood fiber.

The first reports in the scientific literature referring to PIXE 

analysis of stamps were published by Johansen et al. (1986) in 

a report also providing “proof of concept” of PIXE’s application to the forensic analysis of art objects, jewelry, and artifacts. 

Various examples of the Swedish “6-ore ringtyp” stamps issued 

in 1872 (Scott 20) (Figure 3), which exist in various shades of 

violet, lilac, and mauve, were analyzed in a Swedish nuclear research center, with the inked paper in the center of the stamp 

Figure 1. The Mexican “Large Numerals” stamps of 1887. Courtesy of the Smithsonian 

National Postal Museum.

Figure 3. The Swedish 6-ore 

“ringtyp” stamp of 1872. Courtesy 

of the Smithsonian National Postal 

Museum.

Figure 2. The 1-centavo green “Large 

Numerals” stamp. Courtesy of the 

Smithsonian National Postal Museum.
8 6 • smithsonian contributions to history and technology

evaluated separately from the inkless edges of the stamps near 

the perforations.

The analysis of the edges provided an assumed contribution from the paper alone. The authors determined that the inks 

appeared to be made from iron-and-lead- or mercury-based 

pigments, with zinc oxide added as a whitener. Johansen et al. 

(1986:48) concluded that “different proportions of the pigments 

give rise to many nuances, towards red and blue, and a visual 

classification is not easy. An objective classification can be obtained by measuring the metal content and plotting the results 

in a suitable way.” In their summary, Johansen et al. (1986:45) 

reported “for one group of stamps clustering of the visually determined nuances occurred in a two-dimensional plot of lead 

versus zinc, while for another group a plot of mercury versus 

zinc showed no such clustering.”

Peisach (1986), a South African scientist, in the same journal issue, was the first investigator to apply PIXE to investigate 

differences between genuine stamps and forgeries. Known forgeries were compared with genuine stamps from the nineteenthcentury South African Republic and South-West Africa, and on 

the basis of multielemental analytical data, the forgeries were 

shown to have different compositions from the genuine stamps. 

Hall and Lee (1990) published the first scientific paper specifically limited to PIXE analysis of postage stamps, in which the 

different chemical compositions of paper and ink were compared. 

In their work, several stamps from the short-lived Taiwanese republic of 1895 (Stanley Gibbons numbers 4–6) (Jeffries, 2011) 

were irradiated in a 4.0 MeV external proton beam. Hall and 

Lee (1990:573) summarized their results by stating, 

the paper and printing inks were compared between 

stamps made from different dies. The elemental analysis revealed that the 4 dies of stamps were printed on 

only 3 different types of paper. A majority of the elements observed in the stamps were printed on only 

3 different types of paper. A majority of the elements 

observed in the stamps were due to contributions from 

the paper except for the red stamps which were due to 

cinnabar (HgS). In addition, the elemental concentrations were different in counterfeit stamps as compared 

to the genuine stamps.

PIXE was utilized in China by Cheng et al. (1996, 1998) to 

determine the ink composition of modern Chinese stamps and 

their reprints. They compared three stamps issued in 1950 by 

the People’s Republic of China (Scott 57–59) with their official 

reprints (Scott 57r–59r), in the same color, design, and printing 

technique, stated by the authors to have been issued in 1995 

(Figure 4).

Although the colors are quite similar to the original issues, 

the 1995 reprints were shown to have much different elemental 

concentrations and/or compositions. For example, the brown 

stamp (Scott numbers 57 and 57r) contains lead and zinc in the 

original printing, which was not present in the 1995 reprints. 

The relative amount of calcium was eight times greater in the 

reprints than in the early printings. Cheng et al. (1998:900) 

concluded that “we still do not know the reason for modifying 

the printing ink for the new edition. Maybe the original type of 

printing ink was no longer available due to technical improvements. However, the PIXE method can be used to distinguish 

between the (original printing) and (reprints) of stamps.” 

More recently, a group of Iranian scientists (Oliaiy et al., 

2009) used (in conjunction with other techniques) a PIXE microprobe (which uses a micrometer-scale proton beam) scanned over a 

square with dimensions of 2.5 mm on each side to analyze various 

areas of ink and paper on eighteen Iranian stamps issued between 

1881 and 1915 and printed in Austria, France, the Netherlands, 

and Iran. The micro-PIXE was able to indicate the characteristic 

elements used for inks of different colors, as well as differences 

in the formulas for philatelic inks of the same colors utilized in 

different countries. Oliaiy et al. (2009) showed a titanium compound had been added to the paper used in the Austrian-printed 

stamps—iron and sulfur contents of green ink were different between the Austrian-printed and French-printed stamps. There 

were differences in chromium and lead levels in orange inks of the 

Iranian-printed and Netherlands-printed examples, as well as other 

differences in brown, black, grey, violet, and silver inks of stamps 

printed in different countries, suggesting (from lack of detected 

metal in some colors) that certain inks were organic in nature.

Voltr and Nejedly (2012) used PIXE to analyze two early 

spurious Czechoslovakian stamps with double overprints on 

Austrian stamps from 1919 depicting Emperor Franz Joseph 

(Figure 5) and a 1920 Eastern Silesia stamp (Scott 5) (Figure 

6), an overprint on a 20-heller green Prague Castle stamp from 

Czechoslovakia, to determine if genuine overprints could be 

distinguished from forgeries. In this case, the two Czechoslovakian stamps carried one genuine and one forged overprint on 

the same stamp, while two examples of the 1920 Eastern Silesia 

stamp were analyzed, one each with genuine and forged overprints. Voltr and Nejedly (2012:238) reported, “In all cases, 

Figure 4. The Chinese 400-yuan brown “Defend World Peace” 

stamp (left) originally issued in 1950 and (right) later reprinted. 

Original courtesy of the Smithsonian National Postal Museum. Reprint courtesy of the author.
number 57 • 8 7

we found barium as the most prominent element, with concentrations one or two orders higher than that of other elements” 

and also discovered “a specific and interesting variation of lead 

concentrations.” 

In the Czechoslovakian double overprints, lead and iron 

levels “were several times higher on genuine overprint than on 

other places” (Voltr and Nejedly, 2012:238). For the Eastern 

Silesia stamp, there was a significant difference in the quantity of 

iron between the genuine and forged overprints, some variation 

in the concentrations of lead, and a much higher quantity of potassium in the genuine overprint. Voltr and Nejedly (2012:239) 

concluded,

We are proposing a hypothesis that the stamping 

dies used shortly after the World War I were made 

from a material different from the one later used for 

falsification and that traces of the material remained 

in the overprints. Falsifier aimed to emulate the properties of the ink but failed to match the composition 

of the stamping die. As another hypothesis, we attribute the difference in potassium to the distinct printing 

houses—stamps A and B were originally overprinted 

in the printing house A. Haase in Prague in 1919, and 

stamp C was overprinted in Unie Praha later on.

Even with careful precautions made in Voltr and Nejedly’s 

experimental setup, the stamps began to show radiation damage 

(discoloration of the irradiated areas) after analysis, forestalling 

any opportunity for further examination.

CASE STUDY: 

PIXE ANALYSIS OF COLOR VARIATIONS 

IN THE 15-CENTAVO MEXICAN 

“MULITAS” STAMPS

The late philatelist Herbert J. Almquist had noted that color 

variations were known, ranging from bluish green (believed to 

be from the earlier printings) to greenish blue (believed to be 

from later printings), on the 15-centavo “Mulitas” stamp (so 

named because it depicts a stagecoach drawn by mules) of the 

Mail Transportation stamp set printed by Mexico from 1895 

to 1898 (Scott numbers 251, 263, 275, and 286) (Figure 7)

(Almquist, 1985). 

Figure 6. The 1920 Eastern Silesia stamp with overprint on 

Czechoslovakia 20-heller green Prague Castle stamp. Courtesy of 

the Smithsonian National Postal Museum.

Figure 5. The 1919 Czechoslovakian double overprint on Emperor Franz Joseph stamp.

Figure 7. The Mexican 15-centavo “Mulitas” stamps of 1895–1898, showing range of color variation, bluish shade 

on left and greenish shade on right. Courtesy of the Smithsonian National Postal Museum.
8 8 • smithsonian contributions to history and technology

Almquist expected that the ink used to print these stamps 

was the same one used to print the 1-centavo green Numeral 

stamp (Almquist, 1988) (Figure 2). Some investigations had 

been made of variations in the paper of the Mail Transportation 

stamps (Schimmer and Bulak, 1972) but not of their ink. PIXE 

was an ideal technique to determine whether these variations 

were due to chemical differences.

Approximately 100 “Mulitas” stamps for sale from commercial stamp dealers were examined. Four stamps, each displaying the most distinctly bluish and greenish color shades, 

were chosen for testing. Proton-induced X-ray emission analyses 

were performed at the Crocker Nuclear Laboratory at the University of California-Davis (UCD) with an external beam (in air) 

PIXE proton milliprobe, as had been done in Almquist’s analyses 

of the “Numerals” stamps (Almquist, 1985). This external beam 

PIXE analytical setup had been used for a large number of archaeometric analyses of papers and inks, including Gutenberg’s 

Bibles (Schwab et al., 1983) and the Vinland map (Cahill et al., 

1987), as well as the philatelic works of Almquist (1985, 1986, 

1988). The 193-cm isochronous cyclotron at UCD produced a 

beam of protons with energy of 4.5 MeV, which was taken into 

approximately 3 cm of air, passed into the stamps generating 

characteristic X-rays, and collected in a Faraday cup. The beam 

size was a rectangle 1.0 × 0.5 mm for these analyses and was 

aligned by a laser to irradiate specific spots on the sample for 100 

seconds. Prior analyses of historical papers and inks analyzed in 

this laboratory under the same setup had not been reported to 

cause any noticeable damage to samples, and no discoloration or 

other observable damage to the stamps was caused by these analyses. A lithium-drifted silicon energy–dispersive detector (SiLi 

detector) was placed several centimeters from the sample, presenting a large solid angle for X-ray detection and measurement. 

X-rays from the sample were counted at rates of approximately 

700–1500 per second for the samples analyzed here. A thin film 

multielemental standard material from the National Institute of 

Standards and Technology was also analyzed during the run to 

ensure that reported concentrations were accurate and traceable. 

A dark area of solid ink near the top frame of each stamp of 

the four greenish and bluish stamps (away from any cancellation mark) was analyzed, as well as a portion of the unprinted, 

uncanceled paper in the top margin of all eight stamps. 

Only eight chemical elements were detected in the ink and 

paper of the stamps. Three elements were present at relatively 

high densities, exceeding a microgram per square centimeter: 

zinc, silicon, and sulfur. Five “trace” elements were detected at 

lower concentrations: lead, calcium, iron, titanium, and chlorine. Distinct differences in elemental composition between 

bluish and greenish inks of the “Mulitas” were noted, as were 

differences between the “Mulitas” inks and papers and those of 

the “numerals” analyzed by Almquist (1986, 1988) using the 

same machine and experimental setup.

Unlike the “Numerals” stamps (Figure 1) previously analyzed by Almquist (1985, 1986, 1988), which were apparently 

printed with potassium-and iron-based, chromium-bearing inks 

on papers with clay (magnesium, silicon, aluminum, and calcium) coatings or fillers, the absence or much lower concentrations of these elements in the “Mulitas” stamps suggests they 

may have been printed with organic-based inks on papers largely 

devoid of clay fillers. This and the presence of sulfur suggests that 

Mexican stamps could have been printed with aniline (sulfonederived organic) pigments earlier than 1899, as had been previously thought (Schimmer and Bulak, 1972). The “Mulitas” 

paper is harder and stronger than the “Numerals” paper, which 

was easily torn, perhaps due to the latter’s clay- and calciumbased fillers. The “Mulitas” paper is noticeably lower in calcium 

than other eighteenth-century papers investigated in prior PIXE 

analyses (Cahill et al., 1981). 

Oxides or hydroxides of zinc, lead, and/or titanium were 

often added to Mexican (Almquist, 1985, 1986) and other 

(Johanson et al., 1986; Hall and Lee, 1990; Voltr and Nejedly, 

2012) postage stamp inks of the late nineteenth century as brighteners, lighteners, or extenders. The presence of these elements 

in the “Mulitas” inks, along with their relative scarcity in the 

paper, suggests they were modulated color shades of the “Mulitas” stamps, with bluish inks having more zinc and lead and less 

titanium and greenish inks having less zinc and lead and more 

titanium. These elements could have either directly influenced 

the shade of the ink as printed or secondarily protected against 

a postprinting color change of the stamps potentially caused by 

the sulfur in the inks.

conclusions

Proton-induced X-ray emission spectrometry has been a useful technique for the analysis of philatelic inks and papers for 

more than 30 years. Although the machines required to perform 

a PIXE analysis are relatively few and not commercially available, 

when this method can be utilized, its ability to determine low concentrations of metals, for example, in organic-based inks and papers, keeps it relevant. PIXE analysis has shown that a widely used 

practice controlling color shades of nineteenth-century stamp inks 

was the addition of metal oxides as whiteners. In addition, the papers used to print stamps of that era from many entities contained 

clay mineral elements as fillers. PIXE also has shown utility as a 

forensic tool, through its ability to discriminate chemical differences between original, genuine stamps and forgeries or reprints. 

The case study of the 1895–1898 Mexican “Mulitas” 

stamps indicated that they, unlike the previous Mexican issues, 

were printed with organic-based inks on largely clay-free papers. 

Mexican stamps appear to have been printed with organic inks 

several years earlier than previously believed. Differing amounts 

and/or formulations of metal (Zn, Pb, and Ti) oxide whiteners 

apparently controlled the present-day color shade of the stamps, 

either directly or indirectly, with bluish inks having relatively 

more Zn and Pb and greenish inks having relatively more Ti. 

PIXE is one of many tools described at the First International Symposium on Analytical Methods in Philately that have 
number 57 • 8 9

been used for philatelic analyses. Since PIXE is an elemental 

analysis technique, it may be combined with other techniques 

determining the actual chemical compounds or molecules for 

a more complete nondestructive analysis. In conjunction with 

PIXE or XRF elemental analyses, other methods that have been 

successfully applied to stamps, such as Fourier transform infrared spectroscopy (Poslusny and Daugherty, 1988; Ferrer and 

Vila, 2006), Raman spectroscopy (Castro et al., 2008; Jelovica 

Badovinac et al., 2010; Withnall et al., 2012), and/or X-ray diffraction (Foner and Adan, 1983; Liston, 2005; Vila et al., 2007; 

Lera et al., this volume; Brittain, this volume) should be able to 

discern the specific component compounds of the ink and paper. 

Acknowledgments

This paper is dedicated to the late H. J. Almquist (1903–

1994), who inspired the investigation. Thanks are given to 

Thomas A. Cahill, the Crocker Historical and Archaeological 

Projects (CHAPs), and others at the University of CaliforniaDavis for access to the PIXE analytical facilities and the Office 

of Research and Sponsored Projects at the University of Texas 

at El Paso for partial support. Additional thanks are given to 

other attendees of the First International Symposium on Analytical Methods in Philately for constructive discussions and 

suggestions.

NOTES

1. When the Vinland map, supposedly a fifteenth-century map of the Earth, 

was analyzed by PIXE, titanium was found to be a component of the ink; other 

analytical techniques suggested that the titanium was in the form of the compound 

anatase, a material not synthesized in such a form until the twentieth century. 

2. The Crocker Nuclear Laboratory at the University of California-Davis, 

one of the first institutes where PIXE was used for analysis of historical inks and 

papers, was named after University of California Regent William Henry Crocker 

(1861–1937), who not only funded one of the first cyclotrons in the university 

system but also was a philatelist and one of the 100 founding members of the Collectors Club of New York.

3. All references herein to “Scott” refer to the catalogue numbers and, where 

specified, watermark numbers, assigned in the Scott Standard Postage Stamp Catalogues, published every year by Scott Publishing Co., Sidney, Ohio.

REFERENCES

Allen, J. A., and T. Lera. 2013. “The U.S. 1851 3¢ Stamp: Color, Chemistry, and 

Changes.” In Proceedings of the First International Symposium on Analytical 

Methods in Philately, pp. 71–81. Smithsonian Contributions to History and 

Technology, No. 57. Washington, D.C.: Smithsonian Institution Scholarly 

Press.

Almquist, H. J. 1985. Color of the Ledger Lines of the Large Numerals Issue of 

Mexico, 1887. American Philatelist, 99:241–242.

———. 1986. Color of the Ledger Lines of the Large Numerals of Mexico, 

1887—Supplementary Report. Mexicana, 35:207–208.

———. 1988. Comparative Analyses of the Papers Used for the Lined Numerals 

and Following Issues. Mexicana, 37:42–43.

Brittain, H. G. 2013. “Infrared Spectroscopic and X-Ray Diffraction of the Typographed Confederate 5¢ Stamps.” In Proceedings of the First International 

Symposium on Analytical Methods in Philately, pp. 47–55. Smithsonian 

Contributions to History and Technology, No. 57. Washington, D.C.: Smithsonian Institution Scholarly Press.

Cahill, T. A., B. Kusko, and R. N. Schwab. 1981. Analyses of Inks and Papers 

in Historical Documents through External Beam PIXE Techniques. Nuclear 

Instruments and Methods in Physics Research, 181:205–208. http://dx.doi

.org/10.1016/0029-554X(81)90607-8. 

Cahill, T. A., D. W. McColm, and B. H. Kusko. 1986. Control of Temperature in 

Thin Samples During Ion Beam Analysis. Nuclear Instruments and Methods in Physics Research B, 14:38–44. http://dx.doi.org/10.1016/0168-583X

(86)90420-9. 

Cahill, T. A., R. N. Schwab, B. H. Kusko, R. A. Eldred, G. Moller, D. Dutschke, 

D. L. Wick, and A. S. Pooley. 1987. The Vinland Map, Revisited: New 

Compositional Evidence on Its Inks and Parchment. Analytical Chemistry, 

59:829–833, http://dx.doi.org/10.1021/ac00133a009.

Castro, K., B. Ábalos, I. Martínez-Arkarazo, N. Etxebarria, and J. M. Madariaga. 

2008. Scientific Examination of Classic Spanish Stamps with Colour Error, 

a Non-invasive Micro-Raman and Micro-XRF Approach: The King Alfonso 

XIII (1889–1901 “Pelón”) 15 Cents Definitive Issue. Journal of Cultural 

Heritage, 9:189–195. http://dx.doi.org/10.1016/j.culher.2008.02.001.

Cesareo, R., and A. Brunetti. 2008. X-Ray Fluorescence-Analysis of 19th Century 

Stamps. X-Ray Spectrometry, 37:260–264, http://dx.doi.org/10.1002/xrs

.1011. 

Cheng, H., Y. Ding, W. He, F. Yang, J. Tang, Z. Yang, and G. Chen. 1996. The 

Identification of the Republication and First Publishing Postage Stamps by 

PIXE [in Chinese with English abstract]. Sciences of Conservation and Archaeology, 1996-02.

Cheng, H., Y. Ding, W. He, and F. Fujia. 1998. Non-destructive Analysis and Appraisal of Paper-Like Objects. Nuclear Instruments and Methods in Physics Research B, 136–138:897–901. http://dx.doi.org/10.1016/S0168-583X

(97)00759-3.

Demortier, G. 1991. Review of the Recent Applications of High Energy Microprobes 

in Arts and Archaeology. Nuclear Instruments and Methods in Physics Research B, 54:334–345. http://dx.doi.org/10.1016/0168-583X(91)95535-L. 

Ferrer, N., and A. Vila. 2006. Fourier Transform Infrared Spectroscopy Applied 

to Ink Characterization of One-Penny Postage Stamps Printed 1841–1880. 

Analytica Chimica Acta, 555:161–166. http://dx.doi.org/10.1016/j.aca.2005

.08.080.

Foner, H. A., and N. Adan. 1983. The Characterization of Papers by X-Ray Diffraction (XRD): Measurement of Cellulose Crystallinity and Determination 

of Mineral Composition. Journal of the Forensic Science Society, 23:313–

321. http://dx.doi.org/10.1016/S0015-7368(83)72269-3. 

Gill, T. E. 2007. “Analysis of 19th Century Mexican Postage Stamps by PIXE.” 

In Proceedings of the XI International Conference on PIXE and Its Analytical Applications, Puebla, Mexico, May 25–29, 2007, Paper PI-42-1. Mexico 

City: Universidad Nacional Autonoma de Mexico.

Hall, G. S., and M. L. Lee. 1990. Applications of PIXE-PIGE in Philately. Nuclear 

Instruments and Methods in Physics Research B, 49:573–576. http://dx.doi

.org/10.1016/0168-583X(90)90312-I. 

Hassanzadeh, A., M. Lamehi-Rachti, P. Oliaiy, J. Rahigi, and F. Shokouhi. 1999. 

External PIXE Analysis of Old Inks and Papers. International Journal of 

PIXE, 9:481–485. http://dx.doi.org/10.1142/S0129083599000590. 

Jeffries, H. 2011. Stanley Gibbons Stamp Catalogue Part 17, China. London: Stanley Gibbons.

Jelovica Badovinac, I., N. Orlica, C. Lofrumento, J. Dobrinica, and M. Orlica. 2010. 

Spectral Analysis of Postage Stamps and Banknotes from the Region of Rijeka in Croatia. Nuclear Instruments and Methods in Physics Research A, 

619:487–490. http://dx.doi.org/10.1016/j.nima.2009.10.174.

Johanson, S. A. E. 1989. PIXE: A Novel Technique for Elemental Analysis. Endeavour, 13:48–53. http://dx.doi.org/10.1016/0160-9327(89)90002-1.

———. 1992. Particle Induced X-Ray Emission and Complementary Nuclear 

Methods for Trace Element Determination. Analyst, 117:259–265. http://dx

.doi.org/10.1039/an9921700259. 

Johanson, E. M., S. A. E. Johanson, K. G. Malmqvist, and I. M. B. Wima. 1986. 

The Feasibility of the PIXE Technique in the Analysis of Stamps and Art 

Objects. Nuclear Instruments and Methods in Physics Research B, 14:45–49. 

http://dx.doi.org/10.1016/0168-583X(86)90421-0.

Kusko, B. H. 1988. Cyclotron Analysis of the Paper and Ink Reveals the Secrets of 

the Written and Printed Word. Literary Research, 13:123–136.

Lera, T., J. Giaccai, and N. Little. 2013. “A Scientific Analysis of the First Issues 

of Chile 1853–1862, London Printing.” In Proceedings of the First Interna-
9 0 • smithsonian contributions to history and technology

tional Symposium on Analytical Methods in Philately, pp. 19–33. Smithsonian Contributions to History and Technology, No. 57. Washington, D.C.: 

Smithsonian Institution Scholarly Press.

Liston, E. M. 2005. The ‘China Clay’ Variety of the 1908–1910 WashingtonFranklin Issues? Collectors Club Philatelist, 84:105–112. 

Malmqvist, K. G. 1986. Comparison between PIXE and XRF for Applications in 

Art and Archaeology. Nuclear Instruments and Methods in Physics Research 

B, 14:86–92. http://dx.doi.org/10.1016/0168-583X(86)90428-3. 

Moseley, H. G. J. 1913. The High-Frequency Spectra of the Elements. Philosophical Magazine, Series 6, 26:1024–1034, http://dx.doi.org/10.1080/147864413

08635052.

Oliaiy, P., D. Agha-Aligol, F. Shokouhi, and M. Lamehi-Rachti. 2009. Analysis 

of Iranian Postage Stamps Belonging to the Qajar Dynasty (18th–20th Century’s) by Micro-PIXE. X-Ray Spectrometry, 38:479–486. http://dx.doi.org

/10.1002/xrs.1202.

Peisach, M. 1986. Ion Beam Analytical Methods for Attempts to Establish the 

Provenance of Archaeological Objects in the Absence of Reference Artefacts. 

Nuclear Instruments and Methods in Physics Research B, 14:99–115. http://

dx.doi.org/10.1016/0168-583X(86)90430-1.

Pillay, A. E. 2000. A Review of Accelerator-Based Techniques in Analytical Studies. Journal of Radioanalytical and Nuclear Chemistry, 243:191–197, http://

dx.doi.org/10.1023/A:1006748104841.

Poslusny, M., and K. E. Daugherty. 1988. Nondestructive Adhesive Analysis on 

Stamps by Fourier Transform Infrared Spectroscopy. Applied Spectroscopy, 

42:1466–1469. http://dx.doi.org/10.1366/0003702884429814.

Preiss, I. L., and S. Robie. 1982. Radioisotope X-Ray Fluorescence in Philately. 

Industrial Engineering Chemistry-Product Research and Development, 

21:676–678, http://dx.doi.org/10.1021/i300008a034.

Sánchez, H. J., and M. C. Valentinuzzi. 2006. Authentication of Postal Pieces 

by Spatially Resolved X-Ray Fluorescence Analysis. X-Ray Spectrometry, 

35:379–382, http://dx.doi.org/10.1002/xrs.924.

Schimmer, K. H., and C. P. Bulak. 1972. The 1895–1898 Mail Transportation Issue 

of Mexico. Mexicana, January:1–40.

Schwab, R. N., T. A. Cahill, and B. H. Kusko. 1983. Cyclotron Analysis of the 

Ink in the 42-Line Bible. Papers of the Bibliographical Society of America, 

77:283–315.

Skelton, R. A., T. E. Marston, and G. D. Painter, eds. 1995. The Vinland Map and 

the Tartar Relation. New Haven, Conn.: Yale University Press.

Thompson, A. R. 1983. Major Breakthrough in the Analysis of Historic Documents. 

TrAC-Trends in Analytical Chemistry, 2:V–VI. http://dx.doi.org/10.1016

/0165-9936(83)85017-1.

Vijayan, V., R. K. Choudhury, B. Mallick, S. Sahu, S. K. Choudhury, H. P. Lenka, 

T. R. Rautray, and P. K. Nayak. 2003. External Particle Induced X-Ray Emission. Current Science, 85:772–777.

Vila, A., N. Ferrer, and J. F. Garcia. 2007. Colored Inks Analysis and Differentiation: A First Step in Artistic Contemporary Prints Discrimination. Analytica 

Chimica Acta, 588:96–107. http://dx.doi.org/10.1016/j.aca.2007.01.071.

Vodopivec, J., J. Budnar, and P. Pelicon. 2005. Application of the PIXE Method to 

Organic Objects. Nuclear Instruments and Methods in Physics Research B, 

239:85–93. http://dx.doi.org/10.1016/j.nimb.2005.06.227.

Voltr, J., and Z. Nejedly. 2012. Measurement of Proton Beam Fluence by PIXE 

Analysis of Residual Gas. X-Ray Spectrometry, 41:235–239, http://dx.doi

.org/10.1002/xrs.2384.

Withnall, R., A. Reip, and J. Silver. 2012. “Raman Spectroscopy Gains Currency.” 

In Infrared and Raman Spectroscopy in Forensic Science, ed. J. M. Chalmers, 

H. G. M. Edwards, and M. D. Hargreaves, pp. 185–204. Chichester: John 

Wiley & Sons. http://dx.doi.org/10.1002/9781119962328.ch4f.

Zeng, X., X. Wu, Q. Shao, J. Tang, and F. Yang. 1990. Radiation Damage in PIXE 

Analysis of Museum Paper-Like Objects. Nuclear Instruments and Methods 

in Physics Research B, 47:143–147. http://dx.doi.org/10.1016/0168-583X

(90)90022-M.
Statistical Estimates of Rare Stamp Populations

David L. Herendeen and Gary C. White

ABSTRACT. This paper describes a statistical method for estimating the population 

of rare stamps from auction catalogs, price lists, expert certificates, and other generally 

available records. The method presented was developed by biologists to estimate animal 

populations. Such estimates are done by first capturing, marking, and releasing specimens and then recapturing them. From these data, statistics may be developed to estimate 

the total population. The latest-generation computer software used for such analyses, 

called MARK, was developed by Gary C. White and others at Colorado State University. 

This paper explains how MARK may be used by everyday philatelists interested in estimating the number of rare or very scarce stamps or covers in their collecting area. The 

methods described do not require one to be a mathematician to use them successfully. 

The methodology is then applied to four test cases in order to illustrate the efficacy of 

the approach.

PHILATELIC BACKGROUND

One of the most difficult tasks facing the stamp collector, researcher, and exhibitor is 

determining the rarity of particular stamps, whether alone or on cover. This is important 

for exhibitors because it allows them to make claims as to the rarity of items in their collections in a quantitative manner. This is usually done with statements such as “number 

reported,” “number recorded,” “number seen by the exhibitor,” or, most important, 

number according to a recognized expert or group of experts with published results. 

Generally, such numbers are based on censuses conducted by a specialist, or groups of 

specialists, often over prolonged periods of time. 

However, experience has shown no matter how well a census is done, just as with the 

U.S. population census, not every item that exists will be included, and other individuals 

will subsequently come to light. Consider, for example, Alexander’s monumental work 

(Alexander, 2001), in which he identified and counted the covers franked with either or 

both of the first two U.S. stamps (Scott 1 and 2)1 owned by more than a hundred collectors over 25 years (Scott Publishing Co., 2012a, 2012b). This census resulted in a 

count of nearly 13,000 covers at the time of publication. A recent update to this census 

(Scheuer, 2012) shows at least 1,300 new examples that have been identified in the intervening years.

Since it is neither practical nor possible to exactly count any given stamp population, perhaps a method that can provide a statistically valid quantitative estimator can 

be developed by transferring an existing technology to the philatelic domain. That is the 

intent of this paper.

David L. Herendeen (deceased), Institute for Analytical Philately, Inc., P.O. Box 8035, Holland, 

Michigan, 49422-8035, USA. Gary C. White, 

Department of Fish, Wildlife, and Conservation 

Biology, Colorado State University, 1474 Campus 

Delivery, Fort Collins, Colorado, 80523, USA. 

Correspondence: Gary.White@ColoState.edu. 

Manuscript received 10 April 2013; accepted 26 

April 2013.
9 2 • smithsonian contributions to history and technology

STATISTICAL BACKGROUND

A branch of statistics that originated in the field of ecobiology is devoted to developing methods for estimating the population of animals in a specific geographical area. Such techniques, 

whose origins can be traced to the 1930s, are commonly called 

capture-recapture methods. For interested readers, the historical 

background is summarized in White et al. (1982). A brief overview of these methods, intended to address the average philatelist, is presented in the following sections.

The Capture-­Recapture Model

The basic premise of this statistical methodology is that by 

trapping animals and marking them, one can recapture them at 

a later time and by simply counting the number of recaptured 

animals can estimate the total size of the animal population. Two 

important assumptions must hold. The first must be the population is closed, that is, there are no births or deaths (demographic 

closure), and the second must be there is no movement in or out 

of the area (geographic closure).

As a simple example, suppose that one wants to estimate the 

number of rabbits in Sherwood Forest. A number of rabbit traps 

are set throughout the forest. The traps are checked the next 

morning. The traps were successful in capturing n1=32 rabbits. 

Each rabbit is then identified with, perhaps, an earmark and released. The traps are then taken away. One week later, the traps 

are reset. This time, n2=50 rabbits are captured. But only one of 

these was earmarked (r2=1). Assuming that the probability of 

trapping any specific rabbit is equal to that of any other rabbit, 

the chances of capturing a marked rabbit may be estimated by

. n

r

N

n

32

1

1

2 2 = =

It is possible to make a simple estimate of the total population,, 

using the Lincoln-Petersen estimator (Cooch and White, 2012). 

The result is

N , . r

n n

1

32 50 1 600 2

1 2 t = = =

This is the general idea, but as one may expect, the real problem 

is not so simple.

Program Mark

Colorado State University has been at the forefront of research in this area since the 1970s. White and others have developed several generations of computer software designed to solve 

this problem using various levels of complexity. This research 

has led to the program MARK (http://warnercnr.colostate.

edu/~gwhite/mark/), which embodies the majority of proven 

methods for solving capture-recapture problems (White et al., 

1982; White and Burnham, 1999).

As will be discussed later in this paper, the methods most usable to estimate rare stamp populations are those that assume a 

closed population. As noted earlier, this simply means that there 

is a stable population: no births or deaths and no immigration 

or emigration. Readers might observe that there may be several 

instances of “death” in a stamp population. This would include 

copies destroyed by mishandling or war, copies that “mysteriously” disappear, and copies that find their way into museum 

collections. This will be discussed in the next section. Also, there 

is no movement in or out of the area being sampled. As will be 

seen, this assumption is always met for the philatelic application.

Program MARK has a number of models for closed population analyses. There are four possible model combinations that 

consider different population dynamics of animals, but do they 

have application to stamps?

The four models, first proposed by Otis et al. (1978), are as 

follows:

• M0: In this simplest model, it is assumed the probabilities 

of capture and recapture are constant. This means there 

is no difference in the chances of capturing or recapturing a specific animal on any occasion.

• Mt

: This model allows for a variation of capture and recapture probabilities as a function of time. Each animal 

may have a different capture probability for different 

times, but these probabilities will be constant for all animals for each trapping occasion.

• Mb: This model allows for the behavior of specific animals 

to affect their probability of capture. For example, there 

are some animals that might enjoy the trapping (trap 

happy) and those that do not (trap shy). However, the 

initial capture probability is the same across time. Further, this model works by seeing a decline in the number 

of new animals captured on succeeding occasions; that is, 

there is a depletion of animals. When such a decline is not 

happening, then the result is an unidentifiable estimate.

• Mh: This model considers the heterogeneity of the population. Heterogeneity in this context means the capture 

probability is different for each animal, but there is no 

variation across time.

Beyond these models, it is also possible to consider these 

different factors (Mt

, Mb, and Mh) in pairs (e.g., Mtb) or even taking all three possibilities simultaneously, resulting in Mtbh. Some 

of these combinations result from the work of other researchers, 

but a detailed list of these is not necessary for this paper.

The most interesting question is which of the four possible 

models most accurately reflects a rare stamp population? As will 

be seen, the estimation of rare stamp populations is quite similar 

to the animal population estimate. Since the stamps are neither 

sentient nor able to learn, there can be no behavioral differences.

THE STATISTICAL ASSUMPTIONS

The typical capture-recapture algorithms have broad applicability, but the single assumption that greatly simplifies their 

application to the stamp estimation problem is the population 
number 57 • 9 3

is closed. While it is true stamps may be lost or destroyed over 

time, this is usually negligible. On the other hand, it is possible 

that a large percentage of very rare stamps may be “lost” to 

museums. Is it necessary to consider this? Yes, it should be considered, and the easiest way to model this is to simply remove 

such stamps from the study and then add them back into the 

results. For example, suppose four of ten copies of a rare stamp 

are in museums. Then an analysis is performed for the other six 

stamps. Assume the model estimates that there is a population of 

eight stamps. Then we add the four museum copies (which are 

known to exist) to the estimate, arriving at 12 stamps (8+4).

In order to use the MARK program successfully, there are 

other necessary assumptions, which, for our problem, are as 

follows:

• Individual stamps maintain their identification over time. 

That is, one can always identify a given sample from 

its perforations, centering, cancel, or context (as on a 

cover). This is easily met for truly scarce stamps.

• All of the stamps are correctly identified when they appear in an auction, price list, or other public forum. Since 

we are dealing with rare items, we may assume photographs or scans are always available. If not, the occurrence is ignored.

• Each stamp has a constant and equal probability of being 

sold during a given capture period. Gates (1991) asserted 

this assumption may be violated because strong upward 

price pressure may cause more of the stamps to “come 

out of hiding.” The first author feels that most of the 

philatelic rarities are not purchased for investment but 

are rather purchased by dedicated collectors and exhibitors who intend to hold them for long periods.

As an example, the mean holding period for the Labuan stamps, 

discussed later in this paper, has been more than 24 years. This 

is real dedication.

SELECTING TEST CASES

In order to test the hypothesis that MARK could be used as 

an important philatelic tool, a number of test cases were selected 

and executed and the results were analyzed. To this end, four 

sample problems were chosen. These analyses were all based on 

earlier detailed census keeping by various researchers. They have 

been selected to incorporate a number of different characteristics. The test cases are described below.

• The first test case considers one of the most spectacular 

errors in U.S. philately: the 24¢ inverted “Jenny” airmail 

stamp issued in 1918 (Scott C3a). This case is important 

because the population of these iconic stamps is precisely 

known.

• The second test case uses the census and provenance data 

for the 8¢ Labuan inverted frame postage due stamp 

(Scott J6a) performed by Herendeen (2006). This case 

provides two sets of data, the census through 2005 and 

then the extension of the census to 2011. Together, these 

allow the predictive capability of MARK to be examined.

• The third is based on the detailed records of Hawaiian 

stamps and covers maintained by Gregory (2012). Specifically, the data used relate to the 5¢ provisional overprint issued in 1853 (Scott 7). This case checks that the 

estimator works as well for covers as for stamps.

• The fourth example studies a scarce U.S. stamp, the data 

for which were provided by the Robert A. Siegel Auction Galleries, Inc. Web site. This stamp is the U.S. 1¢ 

stamp made from coil waste and issued from 1923 to 

1926 (Scott 594). Only the used stamps were considered 

for this study. This case checks results for a less precise 

data set that has many observations based on expert certificates in addition to auctions. With 488 observations, 

this is also the largest set of the test data.

If all of these test cases result in reasonable estimates that correlate well with reality, then it may be concluded that MARK will 

be useful to philatelists.

ASSEMBLING THE DATA

Several steps must be taken to gather the input data for the 

statistical model. These include acquiring the raw data describing the encounters with specific stamps or covers. The data are 

then divided into time intervals for analysis. These procedures 

are described in this section.

Raw Data Acquisition

While often laborious, the assembly of raw data needed 

to perform the statistical analysis is easily done. Using any application software that allows you to enter and sort data (such 

as Microsoft Excel), you simply record each appearance of the 

stamp or cover under consideration. Data sources may include 

auction catalogues, retail price lists, copies of expert certificates, 

and any other similar records. It is most important that all the 

items are illustrated to allow positive identification.

In theory, only two pieces of data are required for each 

observation, but for completeness, three are recommended as a 

minimum. In fact, the collector may wish to include many different data items so that retracing this step will never be necessary. 

The minimal items are as follows:

• The sample identifier. A unique number, or other string 

of characters, which is assigned to each stamp or cover 

identified.

• The location where the sample was captured. This could 

be an auction catalog, price list, expertizing certificate, or 

any other reliable source.

• The date the sample was seen, offered, or sold. Full dates 

are preferable for completeness, but just the year is usually sufficient.
9 4 • smithsonian contributions to history and technology

Examples of these data are seen in Table 1 for the Labuan inverted frame postage-due stamp.

Selecting the Time Interval

Once the basic data have been assembled, the number of 

time intervals representing sampling occasions must be selected. 

This is especially important with rare stamps because the data 

are much sparser than for the typical animal populations.

In a subsequent section, the results of the statistical analyses for different time steps are presented. It appears from these 

results that no great variations in solutions occur (i.e., less than 

a 10% variation). Therefore, the best estimates should probably 

be those obtained from using a one-year time interval as the “encounter occasions.”

APPLYING THE STATISTICAL MODEL

Once the data are assembled, they are entered into an Excel 

spreadsheet. Then, special software, called POPULATION, is 

used to generate the data for MARK. This software has been 

developed by the Institute for Analytical Philately, Inc. (IAP).2

MARK is then executed and the results are produced. This process is described in the following sections.

MARK Input

The MARK program input is a computer text file that has a 

Windows file extension of .INP. While it is possible to create such 

files manually, IAP’s software tool POPULATION3 provides a 

special utility for use with philatelic data. Instead of creating the 

.INP file manually, the user creates a Microsoft Excel spreadsheet 

containing the raw survey data. 

A partial history of the Labuan inverted frame postage-due 

data is shown in Table 1. It contains a unique sample number for 

each of the stamps seen, the “trap,” which is the source of the 

data, an unused column labeled “year,” and the exact date that 

the stamp was seen.

As will be seen in Herendeen (2012) (hereinafter the Users 

Guide), there are many different options available within POPULATION. For example, when executed, POPULATION converts the exact dates into the years for further processing. The 

user might have just as easily entered only the years into the 

spreadsheet.

POPULATION is then executed. The output is simply the 

MARK .INP file. An extract of this file is shown in Table 2. 

Again, a detailed description of the meaning of this data may be 

found in the Users Guide.

MARK Output

After preparing the input data, the MARK program is executed. Step-by-step details are found in the Users Guide. The 

results of MARK are the statistical computation of the stamp 

Table 1. The history of the 8¢ Labuan inverted frame postage 

due stamp.

Sample “Trap” Date

1 Paris 1 May 1907

12 Royal Collection 1 Jan 1920

13 Ferrary 26 Apr 1923

17 Harmer-UK 14 Mar 1932

21 Harmer-UK 23 Mar 1935

27 Harmer-UK 16 Dec 1935

28 Harmer-UK 16 Dec 1935

15 BPA 1 Jan 1936

31 RPSL 1 Jan 1936

18 Harmer Rooke 1 Dec 1937

26 Harmer-UK 10 Oct 1938

14 Klein 21 Feb 1939

7 Harmer-UK 21 Oct 1947

7 Harmer-UK 25 Oct 1949

13 Harmer-UK 10 Jan 1950

3 Harmer 14 Nov 1950

22 Friedl 9 May 1951

10 Harmer-NY 9 Apr 1957

5 Harmer-NY 30 Sep 1958

9 Corinphila 18 Nov 1959

29 Siegel 24 Feb 1966

21 Gibbons 13 Feb 1969

1 Robson Lowe 30 Jun 1971

18 Harmer-NY 25 Feb 1975

6 Harmer-NY 17 Oct 1979

24 Harmer-NY 25 Mar 1981

27 BPA 1 May 1981

2 Gibbons 4 Mar 1982

3 Sotheby 6 Sep 1984

16 Christies 23 Oct 1984

32 RPSL 1 Jan 1989

5 Manning 19 Nov 1989

13 Siegel 1 May 1990

13 Western 8 Dec 1990

3 Shreve 7 Nov 1991

8 Robson Lowe 17 Dec 1991

16 Christies 5 Mar 1992

18 Shreve 23 May 1992

5 Holtz 1 Apr 1993

22 BPA 1 Jun 1993

4 Cherrystone 9 Aug 1993

25 RPSL 1 Jan 1994

19 Christies 9 Mar 1994

3 BPA 1 Feb 1995

19 Harmer-UK 18 Dec 1996

1 RPSL 1 Jan 1997

10 Ivy-Mader 1 Jun 1997

17 BPA 1 May 1999

23 Gibbons 15 Oct 1999

9 Singer 1 May 2000

21 Spink 23 Jun 2001

17 Bennett 24 Jun 2001

19 Spink 23 Feb 2003

20 Spink 21 Jun 2003

15 Dealer Stock 1 Jul 2003

19 Dealer Stock 1 Jul 2003

11 BPA 1 Aug 2003

25 Spink 16 Oct 2003

9 BPA 1 Nov 2003

15 Grosvenor 19 Nov 2003

30 Roumet 27 Jan 2004

33 Brun 1 Jan 2005

28 Victoria 7 May 2005
number 57 • 9 5

population as well as other statistical estimates. A sample output 

is shown in Table 3, which provides the summary of the statistical quantities estimated.

For this simple model, these are p, the probability of capture 

or recapture for all of the stamps on each occasion, and N, the 

estimate for the total stamp population. These statistics include 

the estimate of each parameter and the lower and upper bounds 

of the 95% confidence interval for the estimates. This can be interpreted as the probability of the true answer lying between the 

lower and upper bound being 95% (although the actual statistical description is more complex).

EXPERIMENTAL VALIDATION

To test the applicability for philatelic analysis of the statistical models used by MARK, four sample problems were assembled. These test cases, along with the purpose for each, were 

described in an earlier section. The results of these cases follow.

The Inverted Jenny—­A Closed-Form Comparison: 

Test Case C3a

A single sheet of 100 of the U.S. 24¢ “Jenny” airmail stamp 

was printed in 1918 with the center inverted, as seen in Figure 

1 (Scott C3a).

Amick (1986) presents a very detailed study of the appearances of all 96 of the recorded examples and recounts the details 

of this fascinating discovery and the many intrigues associated 

with it. No information about the missing four stamps has appeared since the initial dispersal of the stamps. 

This test case is particularly interesting for two reasons. 

First, it allows the fidelity of the MARK program to be determined relative to an exact population size known a priori, and 

second, this problem was solved in the philatelic setting (Gates, 

1992) using an earlier generation of capture-recapture software 

called CAPTURE (White et al., 1978). 

The Amick (1986) data were processed using POPULATION, and the results were used as input to the MARK program. 

Table 2. Extract from MARK data created from Excel spreadsheet.

/* Labuan invert through 2005, annual encounters */

/* Number Occurrences = 99: Starting in 1907 ending in 2005 */

/* 1:3 */ 100000000000000000000000000000000000000000000000000000000000000010000000000000000000000000100000000 1 ;

/* 2:1 */ 000000000000000000000000000000000000000000000000000000000000000000000000000100000000000000000000000 1 ;

/* 3:4 */ 000000000000000000000000000000000000000000010000000000000000000000000000000001000000100010000000000 1 ;

/* 4:1 */ 000000000000000000000000000000000000000000000000000000000000000000000000000000000000001000000000000 1 ;

/* 5:3 */ 000000000000000000000000000000000000000000000000000100000000000000000000000000000010001000000000000 1 ;

...

...

/* 29:1 */ 000000000000000000000000000000000000000000000000000000000001000000000000000000000000000000000000000 1 ;

/* 30:1 */ 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000010 1 ;

/* 31:1 */ 000000000000000000000000000001000000000000000000000000000000000000000000000000000000000000000000000 1 ;

/* 32:1 */ 000000000000000000000000000000000000000000000000000000000000000000000000000000000010000000000000000 1 ;

/* 33:1 */ 000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000000001 1 ;

/* Number Observed = 33 */

Table 3. Typical output from program MARK.

Labuan 99 sampling occasions

Real function parameters of {closed capture}

95% confidence interval

Parameter Estimate Standard error Lower Upper

1:p 0.0139593 0.0024567 0.0098795 0.0196905

2:N 43.416165 5.2347971 37.109245 59.403024
9 6 • smithsonian contributions to history and technology

In the 62 years between 1925 and 1986, there were 427 observations of this stamp. The “closed capture” model was used, and it 

was assumed that the probabilities of both capture and recapture 

were equal for all 96 stamps. MARK then found a solution. The 

results, along with those of Gates (1992), are shown in Table 4.

It is noted that the MARK results are of very high fidelity 

and predict that there are 96 examples. The upper bound of the 

95% confidence interval estimates 102 stamps. The much less 

precise results from CAPTURE occur simply because the older 

software had more limitations, especially in the number of occurrences allowed. As a result, Gates (1992) had to make certain 

assumptions that resulted in much greater variations from the 

known number of stamps.

The results shown in Table 4 indicate the methodology embodied in MARK is well suited to solving the philatelic population problem. For the remainder of the paper, the notation 

“[lower CI,prediction,upper CI]” will be used to express the statistics. Thus, the results shown in Table 4 may be stated as

MARK: [96,96,102]

CAPTURE: [94,107,121].

The Labuan Postage-­Due: Test Cases Labxx

The Herendeen (2006) study identified 33 examples of a 

variety of the postage-due stamps issued by the British colony 

of Labuan in 1901 (Scott J6a). These stamps are especially rare 

because, as shown in Figure 2, they exhibit the inverted frame 

error. Unlike the inverted airmail stamp discussed above, these 

stamps were separated into singles prior to sale. They were also 

canceled to order4 at the point of sale with a seven-bar elliptical 

obliterator. The first recorded public appearance was in 1907 at 

an exhibition in Paris. The study found 63 reported instances 

of these stamps from 1997 through 2005, whether appearing in 

public auctions, submitted to expertizing organizations, or found 

in dealers’ stock. There are undoubtedly other appearances not 

uncovered during the study. Interestingly, the MARK algorithms 

are known to be unbiased by the fact that some data are missing.

The 63 observations in 99 years represent a very sparse 

set of data in the statistical sense. If, for example, the statistical 

model assumes 99 one-year “trapping periods,” then only 42 of 

these periods result in finding a “trapped” stamp.

To determine whether the discretization of time plays an important role in the statistical analysis, three cases were run:

• 10-year time steps (10 occasions),

• 5-year time steps (20 occasions), and

• 1-year time steps (99 occasions).

Table 5 compares the results of these three models. There 

is no meaningful difference between them, with the population 

Figure 1. The “inverted Jenny” of 1918. Courtesy Smithsonian 

National Postal Museum.

Table 4. Comparison of statistics for the inverted “Jenny” 

population.

95% Confidence Interval

Study Estimate Lower Upper

MARK 96 96 102

CAPTURE (Gates, 1992) 107 94 121

Figure 2. The Labuan inverted frame postage-due stamp. Courtesy of the Smithsonian National Postal Museum.

Table 5. Comparison of statistics for three different sampling 

intervals.

95% confidence 

interval

Test case Estimate Standard error Lower Upper

LAB10 44 5.71 37 62

LAB20 46 6.26 38 65

LAB99 43 5.23 37 59
number 57 • 9 7

estimate varying from 43 to 46 and the 95% confidence intervals 

varying from 37 to 65. Thus, the sensitivity of the solution to the 

time discretization is small. However, since the execution time 

of the MARK program is so fast for the philatelic application, 

the first author feels it is easier to simply model the data on an 

annual basis.

As will be seen in a subsequent section of this paper, this 

sample problem also allowed a simulated solution for the updated basic data, which shows how the statistics can be used as 

a predictor. 

The Hawaiian Provisional On Cover: 

Test Case Hawaii

The third sample problem is drawn from a Web site called 

Post Office in Paradise.5 The analysis considers the scarce use 

of the 5¢ provisionally overprinted stamp (Scott 7) on cover as 

shown in Figure 3. Gregory (2012) has archived only 18 such 

covers encompassing 66 observations from 1909 until 1999.

A MARK input file was created from these raw data. The 

input matrix had 18 rows and 91 columns. The program was 

executed and resulted in the following estimates for [lower CI, 

prediction, upper CI]: [18,18,24].

The convergence of the estimate to the number observed is 

explained by the large number of occurrences, 91. This is interpreted to indicate that an additional five examples might be found.

The US 1914 1¢ Coil: Test Case US594

The final example analyzes the data for the U.S. 1¢ stamp 

made from coil waste and issued from 1923 to 1926 (Scott 594), 

shown in Figure 4. The Scott catalog indicates that sheets comprised either 70 or 100 stamps. Raw data were obtained from 

the Robert A. Siegel Auction Galleries, Inc. Web site.6 In addition to auction records, many stamps were reported only when 

Figure 3. Cover showing the use of the Hawaiian 5¢ provisional overprint, Scott 7. Courtesy of the Fred Gregory Collection.

Figure 4. Example U.S. 1¢ green, rotary, perforation 11 stamp 

(Scott 594). Courtesy of Robert A. Siegel Auction Galleries, Inc. Sale 

976, Lot 2170, 29 September 2009.
9 8 • smithsonian contributions to history and technology

they received certificates of genuineness, most from the Philatelic 

Foundation.7 These data were all used to form the observation 

base. Only the 88 recorded used copies of the stamp were included because they form a larger sample space than the 18 mint 

examples.

The total number of observations from 1940 to 2008 was 

199. A MARK input file was created from these data. The input 

matrix had 88 rows (one for each stamp) and 69 columns (one 

for each year). MARK was executed, resulting in [lower CI, prediction, upper CI]: [95,101,115]

This is interpreted to indicate that there are probably another 13 stamps yet to appear and perhaps as many as 27 more 

stamps. Considering that at least 100, and probably more, of 

these stamps were printed, this is not surprising.

As an additional check, the plot shown in Figure 5 shows 

the frequency of appearance by decade. Three new examples appeared in the 2000s and 13 in the 1990s. There is no reason to 

believe that others will not appear in the coming years.

PREDICTING THE FUTURE

Four test cases have been analyzed using the MARK program. The results appear to be consistent with the actual stamp 

populations as measured by censuses. Now, how can these statistical estimates be used to predict what might happen in the 

future? Two methods can help in determining this. The first is to 

simulate the passage of time by incrementally analyzing a stamp 

and the second is to actually look at the results of a real case. 

These are both described in this section.

Test Cases US594

With 199 observation of this rare stamp, the U.S. 1¢ stamp 

of 1923 affords the best opportunity to do a simulation of the 

predictive power of these statistical methods. Recall from Figure 

5 that new “discoveries” have been made across the seven decades since the first reported sighting of the stamp.

A simulation will now be made assuming that this methodology had been available in 1980. This is done by simply truncating the database of observations to any given year. To that end, 

the statistics were computed for periods through 1980, 1990, 

2000, and 2008 (the end of the available data). The results of 

these four analyses are shown in Figure 6. This figure shows, 

for each of the decades, the upper and lower bounds of the 95% 

confidence interval (UB 95% CI and LB 95% CI) and the estimate of the number of stamps. One of the interesting characteristics of statistical methods is the more items we see, the more we 

predict exist. This appears to be stabilizing during the full time 

range. The final estimates [95,101,115] are certainly plausible 

and would indicate that the number printed would be at least 

140 or 200 depending on the sheet size.

Figure 5. First appearance of Scott 594 by decade.
number 57 • 9 9

Test Case Labnew

As seen previously, the Herendeen study was published in 

2006, and the data used in the study ended in 2005. The results 

of the MARK analysis were [36,41,54]. Therefore, although only 

33 stamps were in the census, the model estimated that there 

would be 41 examples. What has actually happened?

In the intervening seven years, there have been 16 new observations of the Labuan inverts. Most important, four of them 

were not included in the 2006 census. In other words, there are 

now 37 known examples. Again, the more items seen, the more 

probably exist.

The new data were executed by MARK. The results were 

[40,45,57]. This shows that there is a useful predictive aspect to 

the statistical analyses.

ADVANCED STATISTICAL MODELS

As noted at the beginning of this paper, other models can 

be used to improve the estimates for populations of animals. In 

addition to M0, which has been used for our sample problems, 

there are also Mt

, Mb, and Mh. Furthermore, these may be applied in pairs (e.g., Mtb), or even all three possibilities can be used 

simultaneously, resulting in Mtbh. The multiple-model approach 

leads to a set of models, each with an estimate of N, and hence 

leads to model selection and how to combine the estimates from 

multiple models. This is a topic for future work and is beyond 

the scope of the current paper. 

Other Observations

Usually, statistical methods are at their best when large samples of data are available. As seen, this is generally not the case 

for rare stamps, where individual encounters may span decades. 

How can the MARK program handle situations such as<bl>

• stamps with a known upper bound or

• ultrarare stamps (<4)?

It has already been shown in test case C3A that excellent results 

were obtained for a stamp whose population has a known upper 

bound.

A simple test case was created to determine how MARK 

handles an ultrarare stamp of which only two examples have 

been seen after 150 years. The subject stamps selected were the 

U.S. 1¢ Z grill stamps of 1867 (Scott 85A). Again, the Robert 

A. Siegel Auction Galleries, Inc. maintains an online database 

Figure 6. Stability of simulated MARK solutions over time for Scott 594. Blue: lower 

bound, red: estimate, green: upper bound.
100 • smithsonian contributions to history and technology

of censuses for some rare stamps, including this one. The encounter histories for the two stamps are quite simple. The first 

example was sold in the mid-1920s (assume 1925) to the New 

York Public Library, where it remains. The second appeared in 

1919, 1957, 1975, 1977, 1986, and 1998. 

The input data for MARK thus included seven encounter 

histories from 1919 to 1998. This model was run and resulted 

in a population estimate of [2.0,2.0,2.0]. The statistical estimate 

has converged to the actual census number. This is an excellent 

result.

CONCLUSION

This paper has described a statistical method for estimating 

the number of rare stamps and covers from available records 

such as auction catalogs, price lists, and expertizing organizations. The basic method, well established in the field of wildlife 

biology and implemented in a computer program called MARK, 

was exercised using four philatelic test cases. In each test case, 

the results were completely plausible and correlated well with 

simulated predictions of future appearances of the rare stamps.

In addition, IAP has made available a Microsoft Excel–

based application called POPULATION that allows philatelists 

to go from census data to input to the MARK program. IAP 

has also written a user’s guide for philatelists to use MARK and 

POPULATION to get results without being a domain expert in 

advanced statistical analysis.

ACKNOWLEDGMENTS

The authors acknowledge the following individuals who 

were kind enough to review this work. We acknowledge Thomas 

Lera, Winton M. Blount Chair of Research, Smithsonian National Postal Museum; Richard Maisel, New York University; 

and Scott R. Trepel, president, Robert A. Siegel Auction Galleries, Inc., for their review of this paper and for the useful suggestions that they made.

NOTES

1. Stamps in this paper are referenced by their Scott number as given in Scott 

Specialized Catalogue of United States Stamps (Scott Publishing Co., New York, 

2010) or Standard Postage Stamp Catalogue, Volume 1, Scott Publishing Co., 2008).

2. The Institute for Analytical Philately, Inc. is a nonprofit corporation that 

sponsors research that develops methods for applying scientific methods to the 

solution of philatelic problems. For more information, see www.analyticalphilately

.org. 

3. The Microsoft Excel–based application POPULATION includes software 

to convert the simple observation data into the INP file used by MARK. The actual 

input data are entered into the data spreadsheet. A portion of the test case LAB data 

is shown in Table 1. For complete details, readers are directed to a separate document (Herendeen, 2012) that provides a comprehensive user’s manual for these 

procedures. The PopUtil spreadsheet and manual are available from IAP by going 

to www.analyticalphilately.org and first selecting “Free Software,” then selecting 

“Population” and following all of the instructions found there.

4. Canceled-to-order stamps are those that have cancellations applied before 

they are ever sold to the public. This allows the distributor to set a price not related 

to the face value of the stamps. The Labuan stamps were sold at the British North 

Borneo office in London.

5. The Web site www.hawaiianstamps.com, most often referred to as Post 

Office in Paradise, was created by and is maintained by Fred Gregory. 

6. Robert A. Siegel Auction Galleries, Inc. is one of the premier auction 

houses for U.S. material. In addition, their Web site www.siegelauctions.com includes a number of tools and resources. One of the most important of these is 

census data for many rare U.S. stamps. This was the source of the raw data for the 

US594 test case. Stamp illustrated is census number 594-OG-11. http://www.siegel

auctions.com/dynamic/census/594/594.pdf.

7. The Philatelic Foundation is the leading expertizing organization in the 

United States. It keeps extensive records of the stamps that have been viewed. For 

more information, see http://www.philatelicfoundation.org/.

REFERENCES

Alexander, T. J. 2001. The United States 1847 Issue—A Cover Census. Canton, 

Ohio: U.S. Philatelic Classics Society.

Amick, G. 1986. The Inverted Jenny. Sidney, Ohio: Amos Press.

Cooch, E., and G. White, eds. 2012. “Program MARK: A Gentle Introduction.” In 

Closed Population Capture-Recapture Models, Chapter 14. Missoula: University of Montana. http://www.phidot.org/software/mark/docs/book/.

Gates, C. E. 1992. Prediction of the Number of Existing Copies of Rare Stamps 

from Auction Records. American Philatelist, 106(1):48–49.

Gregory, F. 2012. Hawaii Foreign Mail to 1870, New York: Philatelic Foundation.

Herendeen, D. L. 2006. Labuan 8c Inverted Frame Postage Due Stamp. London 

Philatelist, 114(1):3–25.

———. 2012. Users Guide for Statistical Analysis of Rare Stamps, IAP Report 

2012-001. Holland, Mich.: Institute for Analytical Philately.

Otis, D. L., K. P. Burnham, G. C. White, and D. R. Anderson. 1978. Statistical 

Inference from Capture Data on Closed Animal Populations. Wildlife Monograph 62. Bethesda, Md.: Wildlife Society.

Scheuer, M. 2012. Updating the Census of 1847 Stamps on Cover. Chronicle of the 

U.S. Classic Postal Issues, 64(4):317–328.

Scott Publishing Co. 2012a. Scott Specialized Catalogue of United States Stamps. 

Sidney, Ohio: Scott Publishing.

———. 2012b. Standard Postage Stamp Catalogue. Volume 1. Sidney, Ohio: Scott 

Publishing.

White, G. C., and K. P. Burnham. 1999. Program MARK: Survival Estimation from 

Populations of Marked Animals. Bird Study, Supplement 1, 46:120–138. 

http://dx.doi.org/10.1080/00063659909477239.

White, G. C., K. P. Burnham, D. L. Otis, and D. R. Anderson. 1978. User’s Manual 

for Program Capture. Logan: Utah State University Press. 

White, G. C., D. R. Anderson, K. P. Burnham, and D. L. Otis. 1982. CaptureRecapture and Removal Methods for Sampling Closed Populations. Los 

Alamos National Laboratory Rep. LA-8787-NERP. Los Alamos, N. M.: Los 

Alamos National Laboratory.
Reflectance Spectroscopy 

of Colored Overprints

Lyman R. Caswell

ABSTRACT. This paper describes a new methodology for analyzing overprinted stamps. 

This methodology is based on two procedures. The first performs precise measurements 

of the dimensions of overprints and a statistical analysis of the minor variations present 

among them. The second performs a colorimetric analysis of the ink used for printing 

the overprints. The goal is to determine if these methods can differentiate between overprints made by different printers and if they can allow rapid identification of counterfeit 

overprints. A set of overprinted stamps from post–World War I Hungary was selected 

for testing samples. These stamps had many varieties, were produced by two different 

print shops, and were often counterfeited. After describing the different scientific testing 

performed, this paper outlines general procedures that may be used by other researchers. 

INTRODUCTION

One of the difficult tasks in philately is the scientific analysis of overprints on stamps. 

This observation led Souren (1939:18) to write, in reference to his expertizing organization, “However, no opinion will be advanced on surcharged stamps except as to the condition of the basic stamp. It will necessitate years of preliminary research before scientific 

proof of the true nature of overprints can be determined satisfactorily.”

More than 70 years later, the need for methods that allow overprint identification 

remains extremely high. Two particularly important areas are the ability to precisely 

measure all overprint dimensions and the ability to determine, in a quantitative manner, 

the color of the ink used for the overprint. Identification of color is important in making 

the distinction between different printings of a given stamp design and between genuine 

and counterfeit printings. It can make the difference between a stamp of little value and 

one of great rarity. 

Cost-­Effective Equipment

Developments in analytical instrumentation using various forms of electromagnetic 

radiation permit new methods of examination and analysis of the colors and compositions of the inks of stamps. These techniques have recently been evaluated for, and used 

in, philatelic applications (Lera, 2012; Lera et al., this volume).

Visual color identification is subjective. It is dependent upon the age and the sex of 

the observer and upon the conditions of observation (Herendeen et al., 2011:106). The 

spectrum of the light reflected from the surface of one stamp can be compared with the 

spectrum of the light reflected from a second stamp to determine if the colors of the two 

Lyman R. Caswell, Institute of Analytical Philately, Inc., P.O. Box 8035, Holland, Michigan, 

49422-8035, USA. Correspondence: ruthand

lyman@nventure.com. Manuscript received 10 

April 2013; accepted 26 April 2013.
102 • smithsonian contributions to history and technology

stamps are the same or different (White, 1979), but this comparison does not necessarily describe the colors of the stamps as 

seen by the eye.

More important, the cost of analytical instruments has 

dropped dramatically over the last 10–20 years, allowing the 

proliferation of such devices and increased access to them for 

philatelists. This is greatly facilitated by the facilities at the 

Smithsonian National Postal Museum (NPM).

The VSC 6000

One of the analytical instruments available at the NPM is the 

Foster + Freeman, Ltd. Video Spectral Comparator (VSC 6000). 

This spectrophotometric device allows the quantitative measurement of color, which allows the correlation of reflectance spectra 

with accepted color systems (Foster + Freeman, Ltd., 2011). 

The most widely accepted color systems are those established by the Commission Internationale de l’Éclairage (CIE).1

The proprietary software of the VSC 6000 system uses measured 

reflectance data to compute colorimetry parameters defined by 

the CIE system. 

The human eye has three types of cones, which receive short 

(blue), medium (green), or long (red) wavelengths of light. Humans perceive color because these cones are stimulated by light 

energy. The colorimetry parameters are called the tristimulus 

values, X, Y, and Z. These correspond to the human visual responses to blue, green, and red components of light. A simple 

calculation transforms the tristimulus into the 1976 CIE chromaticity coordinates, u′,v′ (Berns, 2000). 

The chromaticity coordinates are a measure of visible color. 

If the chromaticity values for two different objects are close together, using a simple distance metric, the colors of the two objects will appear either very close or identical to the eye.

The study of the 1919–1920 postage-due stamps of Slovenia 

by Herendeen et al. (2011) has demonstrated the utility of the 

VSC 6000 not only for the measurement of color of stamps but 

also for actual color identification through the use of chromaticity plots. Others have also used the VSC 6000 to study color 

varieties of stamps themselves (DeBlois and Harris, 2011).

THE SZEGED OVERPRINTS

In the spring of 1919, Admiral Miklós Horthy organized 

a counterrevolutionary nationalist government at Szeged, a city 

in southeastern Hungary. This was in opposition to Béla Kun’s 

Communist government that was in control in Budapest. As is 

often the case during wartime conditions, the available stamp 

supplies were confiscated by the group in power. The available 

stamps in the Szeged post office were overprinted “MAGYAR 

NEMZETI KORMÁNYI, Szeged, 1919” (Hungarian National 

Government). A total of 49 different stamps were issued (Scott 

numbers 1–35, B1-4, E1, J1-8, and P1) (Scott, 1998).2 The 

stamps were all issued on 28 June 1919. 

The stamps overprinted for use in Szeged are referenced 

by their design or their postal use. While there were seven of 

these, only the three actually used are shown in Figure 1. They 

are called Harvesters (Figure 1a), Parliament (Figure 1b), and 

postage-due stamps (Figure 1c). 

The format of the overprint, used for all of the stamps, is 

shown in Figure 1d. Although these stamps are listed in most 

catalogues with the so-called Occupation issues, that is, those 

stamps created by occupying military forces, they were issued by 

a valid Hungarian authority (Ettre, 1972a:5–6; Miles, 1993:193–

196). After the Horthy regime became the de facto government 

of Hungary, these stamps were recognized as legitimate issues of 

the Hungarian government (Ettre, 1972a:5–6). 

The Print Shops

The production of the Szeged overprints was carried out by 

two different print shops (Ettre, 1972a; Brainard, 2006). Unfortunately, details of these shops have been lost to time. Since 

the colors of the Hungarian flag are red, white, and green, the 

nationalist government in Szeged decided to use red and green as 

the colors of the overprints. The majority of the stamps received 

red overprints, but stamps on which a red overprint would not 

show well received green overprints. The green overprint has 

been extensively analyzed by the author in an earlier paper 

(Caswell, 2012). 

Figure 1. (a, b, and c) The basic stamps used for Szeged overprints and (d) the overprint setting.
number 57 • 103

As seen in Figure 2, the red overprints from the two print 

shops are visibly different: vermilion from Print Shop 1 and carmine from Print Shop 2. There is no visual difference between 

the green overprints of the two print shops. Print Shop 1 overprints of both colors can be distinguished from other overprints 

by the force of their application, which resulted in ink splash,

that is, thickening of the ink at the edge of each letter, on the 

front of the stamp, and reverse embossing on the back. Print 

Shop 2 overprints have no distinctive features other than color.

About half of the stamps received overprints in each print 

shop. As will be seen, this study developed a method for attributing stamps to the two print shops.

Counterfeits

Like all of the “Occupation” overprints, those of Szeged 

have been extensively counterfeited. The notorious Budapest 

stamp dealer and counterfeiter Géza Tarján produced excellent 

counterfeits late in 1919, apparently using the original plates 

(Fälschungen, 1936). Additional counterfeits originated from 

Prague in 1926 (Die Fälschungenplage, 1926), and there may 

well be counterfeits from other sources (Tyler, 1991). 

For interested readers, Brainard (2006) has provided descriptions of a number of the counterfeits. Many of the counterfeits are easily recognized by bad fonts, characters, and colors. A 

simple example is shown in Figure 3.

Part of the research documented herein presents methods 

for determining how the more subtle counterfeits may be identified by precise measurements or colorimetry. 

SELECTION OF TESTING SAMPLES

A preliminary examination of all of the available Szeged 

stamps was made in order to determine which ones were suitable 

for reflectance spectral measurement. Stamps with overprints that 

showed ink splash and embossing on the reverse were assumed 

to have genuine Print Shop 1 overprints. All overprints with a 

shifted date were assumed to be counterfeit (Caswell, 2012:37).

It was observed that in order to perform any spectrographic 

analyses on the overprints, a portion of the overprint must be 

over an unprinted portion of the stamp and the spot size must 

be small enough that only that portion is illuminated. If this is 

not the case, there may be interference by the reflectance of the 

underlying ink. 

Most of the basic stamps with the Harvesters and the Parliament designs and the postage-due stamps have significant 

unprinted areas beneath parts of the overprints. Thus, with the 

exception of the problem described next, all of these stamps were 

included as samples for testing.

Under a ×10 hand lens, some candidate sample stamps were 

discovered to have tiny, uninked spots within the letters of the 

overprint. Such overprints were eliminated as samples.

Figure 2. The difference in colors between (left) Print Shop 1 and 

(right) Print Shop 2.

Figure 3. The poorly executed forgery on the right has a wildly different ink color 

than the genuine stamp on the left.
104 • smithsonian contributions to history and technology

TEST PROCEDURES

Each of the selected test samples was analyzed using the 

VSC 6000. During testing each stamp was illuminated with a 

100-watt filtered incandescent spotlight. For precise measurements, the stamps were magnified by a factor of four. VSC tools 

for measuring and labeling the stamps were then used. 

For colorimetry analysis, the reflected light was measured 

under ×18 magnification from a small portion of the stamp overprint having an area of 0.03 mm2. The VSC measures reflectance 

as the percent of the light reflected by the sample compared to 

the light reflected from a standard white magnesium carbonate 

tile. The reflectance spectrum of each overprint was measured 

at a minimum of two points. The measurements were usually 

by different operators. The resulting spectra were averaged for 

each stamp. Figure 4 shows typical reflectance spectra for stamps 

with red and green overprints. The color of the curves in the 

figure matches the overprint color. The plot shows data for the 

wavelength range of human vision, 400–800 nanometers (nm). 

RESULTS

This section presents the results of the precise measurements and colorimetric analysis of the overprints of the selected 

samples.

Precise Measurement

Dimensions of stamps and overprints can be measured accurately with the VSC 6000. This capability was used to measure 

the dimensions of the overprints of all stamps in this investigation under ×4.02 magnification. Table 1 gives a summary of the 

overprint measurements of the sample stamps. 

Figure 4. Reflectance curves from the VSC 6000 for typical red and green overprints.

Table 1. Precise overprint measurements of overprints by stamp design.

Mean horizontal Standard Mean vertical Standard

Stamp design distance (mm) deviation distance (mm) deviation

Harvesters 14.28 ±0.19 9.31 ±0.19

Parliament, genuine overprint 15.67 ±0.21 4.86 ±0.12

Parliament, counterfeit overprint 14.29 ±0.11 9.29 ±0.09

Postage due, genuine overprint 16.05 ±0.06 9.66 ±0.03

Postage due, counterfeit overprint 14.72 ±0.14 9.71 ±0.06
number 57 • 105

The table gives two measurements for the different stamp 

designs and the standard deviations of the measurements of different stamps with the same characteristics. The first are the 

mean horizontal distances from the foot of the “Y” of MAGYAR to the foot of the “R” of KORMÁNY (A in Figure 5). The 

second is the vertical distances from the foot of the first “E” of 

NEMZETI to the top of the “S” of Szeged (B in Figure 5).

Several conclusions may be drawn from these data:

• The measurements for the Harvesters design cannot be differentiated by overprint measurement of the sample stamps.

• The vertical distance of the counterfeit overprints on Parliament design stamps is almost double the distance of 

the genuine Parliament overprints.

• Comparison of the Parliament overprints with the Harvesters overprints leads to the conclusion the Harvesters 

setting for the overprint was used in counterfeiting the 

Parliament overprints. 

• The horizontal distance of counterfeit overprints on the 

postage dues is significantly smaller than the genuine 

overprints. The settings the counterfeiter used were not a 

good match with the correct distances.

Colorimetric Analysis

Preliminary measurements with the VSC 6000 showed 

that reflectance spectra from parts of an overprint that overlay 

a printed portion of a stamp were ambiguous. Apparently, reflectance from the ink of the underlying design combined with 

the reflectance of the ink of the overprint, resulting in subtractive mixing. Useful spectra were obtainable only from parts of 

an overprint that lay on an unprinted part of the stamp. Thus, 

measurement was limited to overprinted stamps with significant 

unprinted areas, namely, the Harvesters, the Parliaments, and the 

postage-due stamps. Collecting data from overprints on other 

stamps would have been very difficult.

Colorimetric analyses were performed for all of the red 

overprint samples. Their reflectance spectra were then analyzed 

to determine whether CIE color models could be useful in identifying stamps from the two print shops and in differentiating 

between genuine and counterfeit overprints. This was not the 

case with the green overprints (Caswell, 2012), where the color 

match was so close that it is highly probable that the same ink 

was used.

As noted previously, it is possible to use chromaticity plots 

(u′,v′ ) to group samples into families of perceived colors. It 

has been demonstrated (Herendeen et al., 2011:108) that each 

group can then be enclosed in a convex hull to make the different colors easier to visualize. For the purposes of this paper, this 

hull is used to clearly differentiate between the three shades of 

the overprint.

Figure 6 presents the chromaticity plot for the carmine, 

vermilion, and rose-carmine overprints. It also shows the convex hulls that enclose the group of samples that have each of 

these colors. The carmine convex hull contains the points for 

both genuine Print Shop 2 overprints and counterfeit overprints. 

The convex hull for the vermilion overprints contains genuine 

Print Shop 1 overprints. The lack of overlap of these convex 

hulls is in agreement with the observation that the colors of 

these overprints are visually different. The unusually shaped 

rose-carmine convex hull is disjoint from the other two, which 

is consistent with its different color. Szeged overprints of the 

rose-carmine color have not previously been described in the 

philatelic literature.

Figure 7 compares the convex hull of genuine Print Shop 

1 overprints (Hull A) with the convex hulls of other varieties. 

The convex hull of the carmine overprints, shown in Figure 6, 

Figure 5. Location of horizontal and vertical overprint measurements.

Figure 6. Convex hulls for the red-colored overprints.
106 • smithsonian contributions to history and technology

is partitioned into three convex hulls, showing the distribution 

of points for

• genuine Print Shop 2 overprints (Hull B),

• shifted date overprints (Hull C), and

• wrong dimension overprints (Hull D).

The small overlap of Print Shop 2, shifted date, and wrong 

dimension overprints is due to the similarity in color of these 

overprints. The Print Shop 2 overprints are significantly distant 

from the Print Shop 1 overprints, again indicating a clear difference in color. The observation that the convex hull of the wrong 

dimension overprints (Hull D) lies outside the convex hull of 

genuine Print Shop 1 overprints (Hull A) and has only slight 

overlap with the hull of Print Shop 2 (Hull B) is in agreement 

with Brainard’s new conclusion that the wrong dimension overprints are counterfeit,3 rather than a genuine variety, as stated 

by Ettre (1972a). The convex hull of the shifted date overprints 

lies within the convex hull of the wrong dimension overprints 

because these overprints are the same color. They are therefore 

two varieties of counterfeits in agreement with the literature, 

Brainard states.

CONCLUSIONS

This study has demonstrated a useful methodology for 

analysis of colored overprints. The VSC 6000, through use of 

its capabilities to make precise measurements of stamps and to 

perform colorimetric analyses, has been shown to be a powerful 

tool for studying overprints.

The finding that the convex hulls for the overprints with 

the wrong dimensions lie outside of the convex hulls for genuine 

overprints was very important. It showed there was a significant 

color difference, thus confirming Brainard’s (2011) conclusion 

that the wrong dimension overprints are counterfeit.4 This corrected an earlier assumption (Ettre, 1972b) that they are genuine varieties. Both wrong dimension overprints and shifted date 

overprints fail to match the convex hull color characteristics of 

either the Print Shop A or Print Shop B overprints. These data 

are in agreement with Brainard’s conclusions that they are two 

varieties of counterfeits.

ACKNOWLEDGMENTS

This work was supported in part by a grant from the Institute for Analytical Philately, Inc. (IAP). I thank David L. Herendeen, president of IAP, for his encouragement and support and 

for providing the software for computing convex hulls. Thanks 

are also due to Thomas Lera, Winton M. Blount Chair in Research at the Smithsonian National Postal Museum. Not only 

did the NPM provide the VSC 6000, but Mr. Lera also assisted 

in training the author in the use of the device and in data collection. Finally, thanks to Christopher E. Brainard, who provided 

a transcript of his notes on his study of the Szeged overprint 

proofs.

Figure 7. Identifying print shops by carmine colors.
number 57 • 107

NOTES

1. CIE, the Commission Internationale de l’Éclairage (International Commission on Illumination), formed in 1913, is the international organization that 

develops standards for everything having to do with light and color. They have 

had a number of color standards through the decades used for color matching. 

For more information, visit their Web site at http://www.cie.co.at/main/ (accessed 

6 September 2012).

2. Scott numbers (Scott Publishing Co., 1988) are given for reference, but 

specialized European catalogues may list more varieties.

3. C. E. Brainard, email message to author, 31 May 2011.

4. Brainard, email message.

REFERENCES

Berns, R. S. 2000. Billmeyer and Saltzman’s Principles of Color Technology. 3rd 

ed., New York: John Wiley & Sons.

Brainard, C. E. 2006. Catalog of Hungarian Occupation Issues,1918–1921. Cherry 

Hill, N. J.: printed by author.

Caswell, L. R. 2012. Evaluation of Forensic Methods for Overprint Analysis. Collector’s Club Philatelist, 91(1):35–45.

DeBlois, D., and R. D. Harris. 2011. The Colors of Martin Van Buren: An Engraved Postage Stamp (1938–1959). Prexie Era. 52: Supplement 1.

Die Fälschungenplage. 1926. Donau-Post, 9:71–77.

Ettre, L S. 1972a. Overprints of the Hungarian National Government in Szeged. 

News of Hungarian Philately, 3(3):11–13.

———. 1972b. Overprints of the Hungarian National Government in Szeged (Continued). News of Hungarian Philately, 3(4):5–6.

Fälschungen. 1936. Die Postmarke, 372/373:314.

Foster + Freeman, Ltd. 2011. VSC 6000. Video Spectral Comparator Software 

Manual. Evesham: Foster + Freeman.

Herendeen, D. L., J. A. Allen, and T. Lera. 2011. Philatelic Shade Determination 

Based on Measured Color. London Philatelist, 120(1384):105–117. 

Lera, T. 2012. In the National Postal Museum. Research: Scientific Equipment at 

the NPM. Collectors Club Philatelist, 91(3):174–178.

Lera, T., J. Giaccai, and N. Little. 2013. “A Scientific Analysis of the First Issues of 

Chile 1853–1862, London Printing.” In Proceedings of the First International 

Symposium on Analytical Methods in Philately, pp. 19–33. Smithsonian Contributions to History and Technology, No. 57. Washington, D.C.: Smithsonian 

Institution Scholarly Press.

Miles, D. 1993. Reference Book of Overprints on Hungarian Stamps. St. Ives: 

printed by author.

Scott Publishing Co. 1988. Standard Postage Stamp Catalogue. Volume 3. Sidney, 

Ohio: Scott Publishing. 

Souren, Y. 1939. Philately of Tomorrow, Vol. 1. New York: Philatelic Research 

Laboratories. 

Tyler, V. E. 1991. Philatelic Forgers: Their Lives and Works. Sidney, Ohio: Amos 

Press.

White, R. H. 1979. Color in Philately. New York: Philatelic Foundation.

A Comparative Study of Security Measures 

Used by Stamp Printers

Garfield Portch and Charles J. G. Verge

The purpose of this paper is to document the learning steps undertaken by the 

authors to understand the features of the Foster + Freeman, Ltd. Visual Spectral Comparator (VSC 6000) for use in expertizing philatelic submissions at the 

Vincent Graves Greene Philatelic Research Foundation. With no published guide to the 

philatelic use of this machine to render expert opinions, there was a need to discover its 

applications and processes. As a project, the authors undertook to look for, discover, 

identify, and compare the individual and common security features used by Royal Mail in 

the United Kingdom and by the Canada Post Corporation in Canada during the production of their high-value definitives in the 1980s, 1990s, and 2000s, including Canada’s 

$10 Blue Whale definitive—2010 (Figure 1). After familiarization with some of the VSC 

6000’s many features, the authors applied their newfound skills to a tobacco excise stamp 

recently introduced in Canada before using philatelic material sent in by clients to the 

Greene Foundation’s expert committee. Each of the steps of the project is detailed in this 

paper. The complete paper will be published in The Canadian Philatelist and the PowerPoint presentation can be found at http://www.analyticalphilately.org/symposium.html.

Garfield Portch and Charles J. G. Verge, Vincent Graves Greene Philatelic Research Foundation, P.O. Box 204, Postal Station Q, Toronto, 

Ontario, M4T 2M1, Canada. Correspondence: 

cjgverge@rogers.com. Abstract received 10 April 

2013; accepted 26 April 2013.

Figure 1. Canada’s highest-value denomination and largest stamp: the $10 Blue Whale. The 

use of fluorescent inks for the scuba diver and the krill is shown using ultraviolet light at 365 

nm. Courtesy the Greene Foundation.

This PowerPoint presentation describes investigations carried out over the last 

two years studying the authenticity of inks used for postal markings on colonial 

stampless letters (Figure 1). After exploring various possibilities, a new spectrophotometric method, called CONTRA TEST, has been developed. The presentation presents the details of this method and shows it is a viable way to expertize such preadhesive 

items. When spectral curves intersect at three or more points, the color obtained presents 

differences in composition, which in turn suggests that the color is difficult to reproduce. 

One would need to know the nature of the pigments and color measuring systems in 

order to forge the color and composition of the ink. The PowerPoint presentation can be 

found at http://www.analyticalphilately.org/symposium.html.

Dieter Bortfeldt, 2511 NW 72nd Avenue, Miami, 

Florida, 33122, USA. Correspondence: colomphil

@usa.net. Abstract received 10 April 2013; accepted 26 April 2013.

New Ways of Looking at Prephilatelic Inks

Dieter Bortfeldt

Figure 1. Colonial letter from Santiago, Chile, to Lima, Peru. Courtesy of the Ponce Collection, Lima, Peru.

This PowerPoint presentation describes how current developments in analytical 

philately were used by a layman, that is, someone without formal scientific training, to determine that an exciting, newly discovered U.S. postal history item was 

not a fake. Access to the equipment used was provided by the Smithsonian National 

Postal Museum. It included the Foster + Freeman, Ltd. Video Spectral Comparator 6000, 

the Bruker Tracer III SD X-Ray Florescence Analyzer, and the Bruker Alpha FT-IR. The 

author used these analytical tools to determine if there were any anomalies along the cut 

sides of a bisected stamp, the application of the cancellation, or the chemistry of the sheet 

to which the stamp was applied (Figure 1). The PowerPoint presentation can be found 

at http://www.analyticalphilately.org/symposium.html. A detailed article was published 

in The Chronicle (Cipolla, 2013) and in the 26 March 2013 Robert A. Siegel Auction 

Catalog, Sale 1041A.

REFERENCES

Cipolla, Roland H., II. 2013. Discovery: Bisected Use of One-Cent 1851 Stamp. Chronicle, 65(1):37–46.

Robert A. Siegel Auction Catalog, 26 March 2013, Sale 1041A, Lot 1179A, the 1851 Half-Cent Bisect, http://

www.siegelauctions.com/2013/1040/1040A.pdf (accessed 17 June 2013).

Roland H. Cipolla II, 15333 E. Westridge Dr., 

Fountain Hills, Arizona, 85268, USA. Correspondence: ron@cipolla.org. Abstract received 10 

April 2013; accepted 26 April 2013.

A Layman’s Forensic Adventure

Roland H. Cipolla II

Figure 1. Diagonal half of a 1¢ 1851 U.S. stamp, type 4, 

tied by a “NEW HAVEN CONN JUL 29” circular date 

stamp to a printed circular, internally dated 1853 and addressed to Hartford. Image courtesy of the author. 

Scholarships at the 

Smithsonian National 

Postal Museum

The Smithsonian National Postal Museum (NPM) is pleased to announce five 

scholarships, available to scientific, academic, and philatelic scholars, for the research of postal operations, postal history, and postage stamps, including scientific 

analysis. The purpose of the scholarships is to enable a block of uninterrupted project 

research time in the NPM or other Washington, D.C., libraries and access to its scientific 

equipment to help solve philatelic questions. Research can include any topic supported 

by the NPM collections, including the international collections, research in the history of 

the post in any century, or scientific analysis of personal collections. The end result of the 

research will be publication as a dissertation, an original article, or a chapter in a book.

Scholarships are from the Smithsonian National Postal Museum and the Confederate Stamp Alliance (CSA), the United States Stamp Society (USSS), 2006 World Philatelic 

Exhibition, and National Philatelic Exhibitions of Washington, D.C., Inc. (NAPEX).

Applications will be accepted throughout the year for these scholarships, which 

range from $500 to $2,000.

Applications should include

• an outline of the subject to be studied and how it relates to the applicant’s previous philatelic, scientific, or postal operations or postal history research;

• intentions as to publication of the results after completion of the project; 

• an accurate cost of the trip(s), including places and organizations to be visited 

and collections to researched; and 

• a short curriculum vitae (including personal details, collecting interests, previous 

publications, and philatelic achievements).

For additional information and application for each scholarship, see http://www

.postalmuseum.si.edu/scholarships/index.html or e-mail npmresearchchair@si.edu. 

Application for an 

IAP Research Grant

The initial application should include information describing yourself and your 

proposed research effort. This information will be used to evaluate the merits of 

the proposed work and its relationship to the mission of the Institute for Analytical Philately, Inc. (IAP). You will then be contacted by one of the institute’s directors to 

further discuss your proposal. The greatest weight is given to projects that develop new 

methodologies promising to be of lasting significance to philately. 

Good proposals result from clearly thought-out plans for your project. The organization of a proposal should always be the same because you are trying to convince a 

“buyer” that you are “selling” a great product. The proposal should include the following information.

EXECUTIVE SUMMARY

This section should describe the project you plan to do, why it important, and how it 

will benefit philately. This is where you get to shine. Write this section for a manager who 

has no idea of what the technical details are but who can immediately grasp the potential 

and importance of your idea.

TECHNICAL APPROACH

This is the technical meat of your proposal. In this section, describe the tasks you 

will perform and the manner in which you plan to perform them successfully. Ideally, you 

should also estimate the scope (for our purpose in elapsed calendar time) so you will later 

be able to develop a project schedule.

STATEMENT OF WORK

This is a recap of the tasks you have defined in the Technical Approach and can be 

used to determine if your plan is succeeding. It is also incorporated in the Research Grant 
118 • smithsonian contributions to history and technology

Agreement you enter into with IAP. In many cases, the Technical 

Approach and Statement of Work can be combined.

COST AND SCHEDULE

Estimate the amount of funding you will need to perform 

your effort, remembering that all IAP grants are firm, fixed-price 

agreements, and agreeing to perform the tasks set forth in the 

Statement of Work for a set fee. Grants typically range from 

$2,000 to $4,000 and are intended to help fund travel, lodging, 

and laboratory use. Additional funding may be available through 

cost sharing with alliance members, who can also provide advice 

on previous work done in a particular area or help in conceiving 

and planning a research effort. (See the Preface on page vii.) 

FINAL REPORT AND PUBLICATION

In this section you present an outline of how you expect your 

final report will look and indicate the technical and philatelic 

journals to which you will submit your article or paper beyond 

possible publication under IAP auspices.

RÉSUMÉ

In this section you provide a summary of both your professional and philatelic accomplishments. It is neither necessary 

nor desired that you provide long lists of technical papers you 

may have authored during your career. It sufficient to make statements such as “. . . resulting in dozens of journal articles.” A 

professional scientific background simply adds additional credence to your proposal and helps convince the reviewer there is 

a good probability the project will satisfy its goals.

Additional information and application for each research 

grant can be found at http://www.analyticalphilately.org/applying

foragrant.html.
The Symposium 

Feedback Session

EQUIPMENT

Suggestion: Provide a summary of machine abilities to allow both IAP directors as well 

as applicants to determine likelihood of research problem success (in simple English). 

Answer: We plan to do this. 

Question: Is it possible to develop a method to measure the age of gum? Some early 

stamps were used without any cancellations, so one could forge a cover where cancellations were not used. 

Answer: Many gums were used, more than most people think, especially for the classic 

stamps. Moreover, gum and gum recipes are very complex compounds (natural products) 

of the basic elements carbon, hydrogen, and oxygen. So analytical “fingerprints” are 

not as clear or certain. However, if modern antioxidants are detected, say, by Fourier 

transform infrared (FTIR) or wet analyses (like butylated hydroxytoluene (BHT) or the 

like), then the gum is a modern gum. Classic gums did not incorporate antioxidants for 

quality purposes. Not all modern gums possess them, either. So if they are not detected, 

then the gum can be modern or earlier. This is not likely and not easily done no matter 

the expense allowed. 

Question: Has the Video Spectral Comparator 6000 (VSC 6000) been used on handstamped overprints? 

Answer: Yes, but there are limitations. 

Question: When using proton-induced X-ray emission (PIXE), what irradiation time 

starts leading to sample damage?

Answer: Usually greater than 5 minutes. 

Question: Can X-ray fluorescence spectrometry (XRF) be used to determine differences 

in sizing or coating for heavier elements?

Answer: It depends and is on a case-by-case basis. 
120 • smithsonian contributions to history and technology

Question: When using PIXE, how long is the sampling time compared with XRF?

Answer: About the same. 

Comment: Be careful when interpreting what the presence of a 

cation means. Without identifying the compound, one cannot be 

sure whether the origin was sizing, brightener, filler, etc. 

Question: Is the VSC 6000 easy to use for the average collector?

Answer: Yes—very easy to learn! 

Question: Can we ask manufacturers to provide basic performance characteristics of their instruments, especially the VSC 

6000, or should we document and distribute them, for example: 

beam size, detection units, precision of measurements, interferences, calibration, linear range, etc.? 

Answer: This is available in the handouts and Wednesday is 

hands on with the manufacturer representatives. 

Question: Can elemental analyses be used to evaluate cancels?

Answer: Yes. 

Question: To determine relative proportions of elements in an 

XRF-tested sample, can one simply integrate the area under the 

curve?

Answer: Sometimes this can be done when the atomic numbers 

of the elements are close together. Otherwise, go to the National 

Institute of Standards and Technology (NIST) Web site (www

.nist.gov) for absorption data. 

COLOR

Question: Are shades due to the inks or the paper (aging, environmental effects, etc.)?

Answer: Both. 

Question: Can we define spectrographically what determines 

shade differences? 

Answer: Sometimes.

Question: Using White’s color plates as a basis, can we define the 

spectra of classic U.S. stamps? 

Answer: Not likely. White’s color plates are pretty accurate for 

the narrow group of stamps they refer to, but beyond that, they 

are very limited in applicability given the great range of colors 

that exist in philately. 

Suggestion: We need to document the effects of various treatments on color, for example, washing, UV exposure, fingerprints, etc. 

Answer: Absolutely; we are looking for the researcher. 

Question: What is a dye? What is a pigment?

Answer: Inks are composed of pigments (the color) and vehicles 

(the liquid) (Figure 1). As shown below, pigments may be animal 

matter, vegetable matter, or minerals. Each type of pigment can 

be identified by the noted analytical device (also note that dyes 

are often deposited on minerals). 

Question: Are there color portfolios that can be used to verify 

color varieties? 

Answer: Some exist, like Ridgway, Pantone, Munsell, etc., but 

they are not adequate. 

PAPER

Question: Permeability: Does ink deposit change it, and does 

permeability change over the surface of the stamp? 

Answer: Yes to both. 

Question: I have heard the word glaze applied to paper. How 

does this differ from sizing? 

Answer: In general, at the most elementary level, most sizing 

is added at the wet end and a glaze is added to finished paper. 

However, there is surface sizing as such which often uses some of 

the same chemicals/coatings that might create a “glaze.” What 

is referred to in Scott’s as glazed paper is a little of a stretch so 

far as glazes go. It was definitely heavily calendared but with no 

obvious coating like most modern glazed papers would have. So 

it is all not quite so black and white. It is not clear if paper in 

question could be analyzed for a “finished coating/glaze that was 

added during finishing.” 

Question: Is it possible that the Continental Bank Note Co. 

paper is denser than that of National? 

Answer: Yes, by 3.5% (due to fines?). 

Question: In the upper-right modulus graph (J. H. Barwis, Paper 

Characteristics of U.S. 3¢ Stamps, 1870–1881, this volume), 

why is R2 1/10th that of the other three? 

Answer: No one knows! 
number 57 • 121

INKS

Question: How did Grinnells get the inks of the genuine stamps? 

Answer: This is not a correct statement. The inks had different 

chemical compositions. See Pearson, Patrick Chilton (2006), The 

Investigation of the Grinnell Hawaiian Missionaries by the Expert Committee of the Royal Philatelic Society London, page 67, 

London: The Royal Philatelic Society. 

Question: How can one clear the background of a negative cancellation so it stands out and becomes readable? 

Answer: This can be done with Photoshop. 

STATISTICS

Question: Statistical population estimates appear to have asymmetric confidence intervals. Why? 

Answer: The confidence interval is modified because we know 

the lower bound from the number of existing stamps. This makes 

the interval asymmetric. 

Suggestion: At the end of the statistics lecture, include info on 

what to do next.

Answer: Great idea—will do. 

Suggestion: How about developing a statistical model of preservation rate on cover versus how many observed and how many 

printed?

Answer: Good potential project idea. 

EXPERTIZATION

Comment: Can we urge the various expert groups to include detailed reasons for “not genuine?” 

Answer: Some do; it is becoming more common, but there is still 

a long way to go. 

Question: Can watermarks be identified without removing a 

stamp from a cover?

Answer: Yes, in some cases, with the use of the VSC 6000. 

Comment: On postal history items, ask the expert why he believes something to be genuine. It would encourage the expert to 

deal more deeply with the whole subject.

Answer: Again, most expert groups do “historical research,” but 

they have not gotten into the habit of sharing the information. 

Suggestion: How about an international board to decide which 

experts should be accepted to avoid auction houses shopping 

around for a “good” certificate on an item already decided to 

be bad? 

Answer: There is such an organization, the Association International des Experts en Philatelie (AIEP). Check their Web site, 

www.aiep-experts.net.

Comment: Certificates shouldn’t be older than five years due to 

technical developments. 

Answer: That is up to the owner, purchaser, or exhibitor. We 

have seen environmental changes to objects, which should also 

mean a new certificate should be obtained.

INTO THE FUTURE

Question: Would you plan to attend a Second International Symposium (Y or N)?

Answer: Y (100%).

Question: Would you recommend attending a future symposium 

(Y or N)? 

Answer: Y (100%).

Question: Would you personally use any of the technology presented (Y or N)? 

Answer: Y (100%).

Question: Do you think others you know might use any of the 

technology presented (Y or N)? 

Answer: Y (100%).

Question: Could you please give the three geographical locations 

you would prefer for a symposium (e.g., Washington, New York, 

London, etc.)? 

Answer: While there was some support for other venues, the 

overwhelming vote was for the NPM because of the ability to 

have the hands-on workshops. 

Question: How often do you think the International Symposium 

should be held (two, three, or four years)? 

Answer: Two years (70%). This was again the overwhelming 

choice and probably optimum for having quality research papers. 

Question: What time of year do you think the symposium should 

be held? 

Answer: Most liked November time frame or other off-season times.
All manuscripts are reviewed for adherence to the SISP Manuscript Preparation and 

Style Guide for Authors (available on the “Submissions” page at www.scholarlypress.si.edu). Manuscripts not 

in compliance will be returned to the author. Manuscripts intended for publication in the Contributions Series are evaluated by a content review board and undergo substantive peer 

review. Accepted manuscripts are submitted for funding approval and scheduling to the Publications Oversight Board. 

Minimum manuscript length is thirty manuscript 

pages. If a manuscript is longer than average, an appropriate 

length will be determined during peer review and evaluation 

by the Content Review Board. Authors may be asked to edit 

manuscripts that are determined to be too long. 

Text must be prepared in a recent version of Microsoft 

Word; use a Times font in 12 point for regular text; be double 

spaced; and have 1” margins. Each chapter/section must be 

saved in a separate file.

Required elements are title page, abstract page, table 

of contents, main text, and reference section. See the SISP 

Manuscript Preparation and Style Guide for Authors for the 

order of all elements.

Headings should be styled so different levels of headings are 

distinct from each other and so the organization of the manuscript is clear. Insert one line space above and one line space 

below all headings.

Front matter should include title page, abstract page, 

and table of contents. All other sections are optional. Abstracts must not exceed 300 words. Table of contents should 

include A-, B-, and C-level headings.

Tables (numbered, with captions, stubs, rules) should be 

submitted in separate MS Word files; should include footnotes, if appropriate; should have rules only at top, bottom, 

and beneath column heads. Print outs of each table should 

accompany the manuscript to ensure correct layout of data. 

Tabulations within running text should not be numbered or 

formatted like formal tables, and should be included in the 

text of the manuscript. 

Figure captions should be provided in a separate MS 

Word file.

Figures (e.g., photographs, line art, maps) should be numbered sequentially (1, 2, 3, etc.) in the order called out; be 

placed throughout text, not at end of manuscript; have all 

components of composites lettered with lowercase letters and 

described in the caption; include a scale bar or scale description, if appropriate; include any legends in or on the figure 

rather than in a caption. 

Art must not be embedded in the main text.

Figures must be original and submitted as individual TIFF 

or EPS files. Resolution for art files must be at least 300 dpi 

for grayscale and color images and at least 1200 dpi for line 

art. Electronic images should measure no more than 100% 

and no less than 75% of final size when published. JPG files 

will not be accepted. Color images significantly increase 

costs so should be included only if required. Funding for 

color art is subject to approval by SISP and the Publications 

Oversight Board.

taxonomic keys in natural history papers should use 

the aligned-couplet form for zoology. If cross referencing is 

required between key and text, do not include page references 

within the key but number the keyed-out taxa, using the same 

numbers with their corresponding heads in the text.

synonomy in zoology must use the short form (taxon, author, year:page), with full reference at the end of the 

paper under “References.”

In-text references should be used rather than bibliographic notes and should follow the author-date system in the 

following format: “(author last name, year)” or “. . . author 

(year)”; “(author, year:page used within the text)” or “. . . 

author (year:page).” A full citation should be included in a 

“References” section.

Endnotes are to be used in lieu of footnotes and should 

be keyed manually into a separate MS Word file, in a section titled “Notes”. Notes should not contain bibliographic 

information. Manually type superscript numerals in text and 

use full-sized numerals at the beginning of each note in the 

“Notes” section. SISP will determine the best placement of the 

notes section, either at the end of each chapter or at the end 

of the main text.

References should be in alphabetical order, and in chronological order for same-author entries. Each reference should 

be cited at least once in main text. Complete bibliographic information must be included in all citations (e.g., author/editor, 

title, subtitle, edition, volume, issue, pages, figures). For books, 

place of publication and publisher are required. For journals, 

use the parentheses system for volume(number):pagination 

[e.g., “10(2):5–9”]. Do not use “et al.”; all authors/editors 

should be included in reference citations. In titles, capitalize 

first word, last word, first word after colon, and all other 

words except articles, conjunctions, and prepositions. Examples of the most common types of citations are provided in the 

SISP Manuscript Preparation and Author Style Guide. 

For questions regarding the guidelines, please email SISP at 

schol.press@si.edu. 

requirements for smithsonian series publication