1_README.TXTThe Effect of Selected CleaningTechniques on Berkshire Lee Marble:A Scientific Study at Philadelphia City HallBy Victor G. Mossotti, A. Raouf Eldeeb, Terry L. Fries, Mary Jane Coombs,U.S. Geological Survey;Virginia N. Naude',Norton Art Conservation, Inc;Lisa Soderberg,Vitetta Group;andGeorge Wheeler,Metropolitan Museum of Art, New YorkProfessional Paper 16352002U.S. Department of the Interior Gale A. Norton, Secretary U.S. Geological Survey Charles G. Groat, Director QUICK STARTFor those already familiar with Adobe Acrobat Reader and who have version 5.0 or greater of this program on their computer, go directly to the file pp1635.pdf.  CONTENTSThis CD-ROM contains Portable Document Format (.pdf) files for the main text of the report (pp1635.pdf) as well as the individual folders of images, data tables, and software.Files:-- 1_README.TXT - this text file in ASCII format-- pp1635.pdf - The text, figures, and tables for this      report presented in the form of an electronic "book"      using Adobe Acrobat Reader.-- Autorun.inf and usgsid.ico - display files for WindowsFolders:-- Acrobat - folder containing installer software-- figures - A folder containing the individual graphic      files used in this paper.  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Subfolders consist of:  "core_surface_photos," "pch_facade_and_detail," and "sem_cut_images."  The "core_surface_photos" subfolder contains 155 images in .jpg format.  The "pch_facade_and_detail" subfolder contains 11 photographs of the facade and detail of Philadelphia City Hall in .jpg format.  These are each about 3072 by 2048 pixels (six megapixels) and are numbered PCH01.jpg through PCH11.jpg.  PCH09.jpg was used for the label and PCH11.jpg was used for the cover of this CD-ROM.  The "sem_cut_images" subfolder contains images generated from the scanning electron microscope.  For information on viewing files from this folder, refer to Mossotti, V.G., Eldeeb, A.R., and Oscarson, Robert, 1998,      MORPH-I (Ver. 1.0), a software package for the      analysis of scanning electron micrograph (binary      formatted) images for the assessment of the fractal      dimension of enclosed pore surfaces: U.S. Geological      Survey Open-File Report 98-248, 74 p.      [URL http://geopubs.wr.usgs.gov/open-file/of98-248]Four programs are contained in the "programs" folder:  EDGE.EXE, PROFILE.EXE, SEM2BIN.EXE, and SHOWPIX.EXE.  These programs are part of a software package for the analysis of scanning-electron-micrograph (binary-formatted) images for the assessment of the fractal dimension of enclosed pore surfaces.  SYSTEM REQUIREMENTSThis CD-ROM (pp1635) was produced in accordance with the ISO 9660 Level 2 standard and Apple Computer's(1) hierarchical file system (HFS) standard.  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The eight cleaning techniques evaluated in this study were power wash (proprietary gel detergent followed by water rinse under pressure), misting (treatment with potable, nebulized water for 24-36 hours), gommage (proprietary Thomann-Hanry low-pressure, air-driven, small-particle, dry abrasion), combination (gommage followed by misting), Armax (sodium bicarbonate delivered under pressure in a water wash), JOS (dolomite powder delivered in a low-pressure, rotary-vortex water wash), laser (thermal ablation), and dry ice (powdered-dry-ice abrasion delivered under pressure).In the quasi-experimental design, a control sample, taken from an area of stone protected by epoxy adjoining an unprotected test area, was simultaneously cored with the test sample. In our study, approximately 160 cores were removed from the building for laboratory analysis. As a basis for differentiating the various cleaning techniques, we measured the changes in the structural properties of the stone on the microscale (0.1-100 micro meters), and in the esthetic features of the stone on the mesoscale (0.1-5 mm) and macroscale (greater than or equal to 0.5 cm), caused by each of the cleaning techniques.The spatial distribution of particulate matter and salts on adjacent control and test surfaces was measured by electron microscopy on the microscale and by optical reflectance on the mesoscale to macroscale (0.1-20 mm). We developed a computer program to analyze scanning-electron-micrograph (SEM) images for the fractal dimension and other morphologic parameters of the stone surface; the fractal dimension is a factor in the surface-roughness test. The program also computed the near-surface fracture density of the stone.An analysis of more than 1,100 samples cut from the cores provided a statistical basis for crafting the essential elements of a reduced-form, mixed-kinetics conceptual model that represents the deterioration of calcareous stone in terms of self-organized soiling and erosion patterns. This model, in turn, provided a basis for identifying the variables that are affected by the cleaning techniques and for evaluating the extent to which such variables influence the stability of the stone. The  model integrates the mutual dependence of processes controlling the primary deposition of soiling agents, the secondary mobilization of transportable materials, and the permanent alteration of the stone through critical feedback paths in the model system.The model recognizes three classes of variables that may influence the soiling load on the stone, including such exogenous environmental variables as airborne moisture, pollutant concentrations, local aerodynamics, and so on, and such endogenous stone variables as surface chemistry and microstructure (fracturing, roughness, and so on). Our study showed that morphologic variables on the mesoscale to macroscale are generally not affected by the choice of a cleaning technique. For example, surface-recession tests indicate that differences in mass loss from technique to technique are virtually inconsequential over the long term. The model also explains the spatial distribution of particulate matter and salts over the building by the action of water on the stone surface. According to this mechanism, the soiling pattern on the building is controlled mainly by the macromorphology and orientation of the stone. Thus, the long-term soiling pattern on the building is independent of the cleaning technique applied.This study also showed that micromorphologic variables are differentially affected by the various cleaning techniques. Although the extent to which surface microstructure and microchemistry influence the soiling load requires further study, we assumed in our evaluation that the long-term esthetic and structural properties of the stone are closely related to the lateral and vertical distribution of particulate matter and salts and to the mechanical bonding between calcite, phlogopite, and dolomite grains in the matrix. Contrary to our original conjecture, we found no evidence that soluble salts play a significant role in the deterioration of Berkshire Lee marble. Although salts were evident in cracks and fissures of the heavily soiled stone, such salts did not penetrate the surface to a depth of more than a few hundred micrometers.Interestingly, we noted that the strength of the relation between the fracture density and the surface roughness was distinctly sensitive to the cleaning technique used, and so we used this relation as a measure of the marginal ability of each technique to clean the stone without causing collateral damage to the surface. Thus, the criteria used to differentiate the cleaning techniques were ultimately based on the ability of each technique to remove soiling without altering the texture of the stone surface. This study identified both the gommage and JOS techniques as appropriate for cleaning ashlar surfaces and the combination technique as appropriate for cleaning highly carved surfaces at the entablatures, cornices, and column capitals.ACKNOWLEDGMENTSThis research was supported by the U.S. National Park Service (NPS)'s National Center for Preservation Technology and Training, the Philadelphia Historical Society, and the city of Philadelphia; development of the SEM image-analysis software (MORPH-I and MORPH-II) was specifically supported by the NPS. Susan Sherwood assisted in organizing the multidisciplinary project team of preservation architects, conservators, and scientists. We also thank Chandra Reedy, ElizaBeth Bede, Susan I. Sherwood, and Richard Tosdal for their reviews of the manuscript.FOR SALE BY:USGS Information ServicesBox 25286Denver Federal CenterDenver, CO  80225Telephone: (888) ASK-USGSThe bibliographical reference for this publication is:Mossotti, V.G., Eldeeb, A.R., Fries, T.L., Coombs,      Mary Jane, Naude', V.N., Soderberg, Lisa, and Wheeler,      G.S., 2002, The effect of selected cleaning techniques      on Berkshire Lee marble:  a scientific study at      Philadelphia City Hall:  U.S. Geological Survey      Professional Paper 1635 (CD-ROM).ISBN 0-607-96243-7This report and any updates to it are available on line athttp://geopubs.wr.usgs.gov/prof-paper/pp1635/     Library of Congress Cataloging-in-Publications DataThe effect of selected cleaning techniques on Berkshire Lee   marble [computer file] : a scientific study at   Philadelphia City Hall / by V.G. Mossotti ... [et al.].  1 computer optical disc ; 4 3/4 in. -- (Professional   paper ; 1635)  Title from disc label.  Audience:  Geologist, monument curators.  Summary:  A scientific investigation of the effects of eight different cleaning techniques on the Berkshire Lee marble component of the facade of the East Center Pavilion at Philadelphia City Hall.  The eight cleaning techniques evaluated were power wash, misting, gommage, combination, Armax, JOS, laser, and dry ice.  ISBN 0-607-96243-7  1. Building stones--Cleaning--Software.  2. Marble--Cleaning--Software.  I. Mossotti, V. G. II. U.S. Geological Survey Library.  III.  Series:  U.S. Geological Survey professional paper ; 1635.TH5520691--dc13                                                 2001016528                                                        CIPDISCLAIMERSThis Compact Disc Read-Only Memory (CD-ROM) publication was prepared by an agency of the U.S. Government.  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