AN IMPROVED PROCESS POR PRODUCING PHOTOGRAPHS IN PIGMENTS
Year: 1869

page_text: LETTERS PATENT to Frederick Richard Window, of Baker Street,
Portman Square, in the County of Middlesex, Photographer, for
the Invention of "AN IMPROVED PROCESS POR PRODUCING PHOTOGRAPHS
IN PIGMENTS."
Scaled the 14th April 1870, and dated the 19th October 1869.
PROVISIONAL SPECIFICATION left by the said Frederick Richard
Window at the Office of the Commissioners of Patents, with his
Petition, on the 19th October 1869.
I, FREDERICK RICHARD WINDOW, of Baker Street, Portman Square,
in the County of Middlesex, Photographer, do hereby declare the nature
of the said Invention for "AN IMPROVED PROCESS FOR PRODUCING PHOTO-
GRAPHS IN PIGMENTS," to be as follows, that is to say :-
The effect of many of the salts of chromic acid acting in conjunction
with actinic light on soluble organic bodies, such as geleatine and gum,
is well known, and is the basis of most of the published carbon printing
processes. Also the formation of photographic images by treating

page_text: surfaces prepared with hygroscopic organic compounds, and a chromate
after insolation, through a photographic negative or positive, as the case
may be, with pigments in powder is well known, and is the basis of
several published methods of producing photographic enamels.
My Invention consists in applying both the chemical action of chromic
salts on soluble organic bodies and the treatment with powdered pig-
ments of surfaces prepared with hygroscopic compounds combined with
a soluble chromate after insolation through a cliché (which for con-
venience I call a negative,) for the production of photographic
impressions on paper, cardboard, wood, ivory, metal, glass, and other
surfaces by the means herein-after described.
I prepare a solution consisting of albumen and some hygroscopic
substance, such as honey, gum, sugar, glucose, or of several of them
combined, according to circumstances, and a soluble chromate. The
solution I prefer using as very suitable for general purposes is composed
of, honey, 2 parts; glucose, 4 parts; albumen, 3 parts; dextrine, 1 part;
saturated solution of bi-chromate of ammonia, 7 parts.
This solution of albumen, a hygroscopic body, and a chromate I call
the sensitive solution. I spread this sensitive solution upon the surface
which is to receive the photographic image, sometimes with a brush or
other convenient means, sometimes by thinning it with water and
pouring it on like collodion; I then dry it by heat, and expose it under
a negative to light. When exposed a sufficiently long time I brush
powdered pigment over the surface until the image is sufficiently
developed. I now proceed to fix the pigment on the surface of the paper
or other material. I effect this by laying the print immediately after
development in a flat dish, and pouring alcohol, naphtha, or some other
such agent over it, wetting both back and front, the print is then hung
up to dry spontaneously, or a gentle heat may be employed. When
quite dry it is immersed in a dish of water acidulated with hydrochloric,
sulphuric, or some other acid which will dissolve out all the soluble
portion of the coating. The print is then soaked for a short time in
clean, water and finally passed through a dish of water rendered slightly
alkaline with ammonia to expunge any trace of acid.
If I want the finished print to have a glazed surface, such as is pro-
duced by silver photographic printing on albuminised paper I use plain
collodion in lieu of the alcohol to fix the picture. In all other points
the manipulations are the same as before described.

page_text: Another mode of securing pigment prints upon paper with a glazed
surface is to prepare a sensitive solution similar to that herein-before
described, omitting the albumen. A glass or metal plate is coated with
this solution, insolated under a negative, and developed with powdered
pigment as is done in some published enamelling processes. After
development collodion is poured over the coated surface, and left to
dry. When perfectly dry it is transferred to gelatine paper or to
albuminised paper according to known and published methods.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Frederick Richard Window in the Great Seal
Patent Office on the 19th April 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, FREDERICK
RICHARD WINDOW, of Baker Street, Portman Square, in the County of
Middlesex, Photographer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Nineteenth day of October, in the year
of our Lord One thousand eight hundred and sixty-nine, in the thirty-
third year of Her reign, did, for Herself, Her heirs and successors, give
and grant unto me, the said Frederick Richard Window, Her special
licence, that I, the said Frederick Richard Window, my executors,
administrators, and assigns, or such others as I, the said Frederick
Richard Window, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at
all times thereafter during the term therein expressed, should and
lawfully might make, use, exercise, and vend, within the United
Kingdom of Great Britain and Ireland, the Channel Islands, and Isle
of Man, an Invention for "AN IMPROVED PROCESS FOR PRODUCING PHOTO-
GRAPHS IN PIGMENTS," upon the condition (amongst others) that I, the
said Frederick Richard Window, my executors or administrators, by an
instrument in writing under my, or their, or one of their hands and
seals, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters
Patent.

page_text: NOW KNOW YE, that I, the said Frederick Richard Window, do
hereby declare the nature of my said Invention, and in what manner the
same is to be performed, to be particularly described and ascertained
in and by the following statement, that is to say :-
The effect of many of the salts of chromic acid acting in conjunction
with antinic light on soluble organic bodies, such as gelatine and gum,
is well known, and is the basis of most of the published carbon printing
processes. Also the formation of photographic images by treating
surfaces prepared with hygroscopic organic compounds and a chromate,
after insolation through a photographic negative or positive, as the case
may be, with pigments in powder is well known, and is the basis of
several published methods of producing photographic enamels.
My Invention consists in applying both the chemical action of chromic
salts on soluble organic bodies, and the treatment with powdered
pigments of surfaces prepared with hygroscopic compounds, combined
with a soluble chromate after insolation through a cliché (which for
convenience I call a negative) for the production of photographic
impressions on paper, cardboard, wood, ivory, canvas, and other surfaces
by the means herein-after described.
I prepare a solution consisting of albumen and some hygroscopic
substance, such as honey, gum, sugar, glucose, or of several of these sub-
stances combined, according to circumstances, and a soluble chromate.
The solution I prefer using as most suitable for general purposes is
composed of honey, two parts; glucose, four parts; albumen, three
parts; dextrine, one and a half parts; saturated solution of bi-chromate
of ammonia, seven parts.
This solution of albumen, a hygroscopic body, and a chromate I call
the sensitive solution. I spread this sensitive solution upon the surface
which is intended to receive the photographic image, sometimes with a
brush or other convenient means, sometimes after thinning it with
water by pouring it on like collodion; I then dry it by means of heat
and expose it under a negative to light. When exposed a sufficiently
long time I brush powdered pigment over the surface until the image is
sufficiently developed, and proceed to fix the pigment on the surface of
the paper or other material, I effect this by laying the print imme-
diately after development in a flat dish and pouring alcohol, naptha, or
some other such agent over it, wetting both back and front; the print is
then hung up to dry spontaneously or a gentle heat may be employed.

page_text: When quite dry it is immersed in a dish of water acidulated with
hydrochloric, sulphuric, or some other acid which will dissolve out all
the soluble portion of the coating. The print is then soaked for a
short time in clean water and finally passed through a dish of water
rendered slightly alkaline with ammonia to expel any trace of acid.
If I want the finished print to have a glazed surface such as that
produced by silver photographic printing on albuminized paper, I usc
collodion alone in lieu of alcohol to fix the picture. In all other respects
the manipulations are the same as herein-before described.
Another mode of securing pigment prints upon paper with a glazed
surface is to prepare a sensitive solution similar to that herein-before
described omitting the albumen. A glass or metal plate is coated
with this solution insolated under a negative and developed with
powdered pigment, as is done in some known enamelling processes.
After development collodion is poured over the coated surface and
left to dry. When perfectly dry it is transferred to gelatine paper
or to albuminized paper according to known methods.
I have found that the developed print may be transferred from the
sensitive coating upon which it has been developed to other surfaces,
provided that the latter have received some coating of a sufficiently
glutinous or tenacious nature to retain it. Paper coated with a mixture
of one part of albumen and three of water, or with one part of gelatine
in twenty parts of water answers for this purpose, all that is necessary
to effect the transfer, being to bring in contact the developed print and
the transfer paper under a somewhat heavy pressure and the application
of moisture, such as a wet paper or sponge placed on the back of the
print. Any plane surface to which a coating of adhesive compound has
been applied will receive the transferred print as well as paper.
I have also found that the developed print may be transferred to stone
or zinc, but for this purpose a somewhat different treatment is necessary.
The print must be developed with a powder of a fatty or resinous nature
or with a pigment powder containing a notable quantity of a fatty body.
Asphalte mixed with one-fourth its weight of paraffin or stearic acid
and reduced to fine powder answers for this purpose, as does also lamp-
black, containing about one-fourth of its weight of stearic acid. The
print developed with these or analogous powders is laid down upon the
stone heated to a temperature sufficient to melt the fatty body mixed
with the pigment and passed under the rolling press. On damping the

page_text: back of the print the fatty powder is left in contact with the stone, and
adheres thereto if the heating has been properly managed, while the
moistened sensitive compound likewise adheres to the stone and forms
a protective coating against the fatty matters when the stone is rolled
up in the usual way. From such a prepared stone a large number of
impressions may be taken.
Having now described the nature of my Invention, and the manner of
carrying the same into effect, what I claim is, the improved process for
producing prints or photographs in pigments on paper, cardboard, wood,
ivory, canvas, and other like surfaces, substantially in the manner, and
for the purposes herein-before described.
In witness whereof, I, the said Frederick Richard Window, have
hereto set my hand and seal, this Eighteenth day of April, in
the year of our Lord One thousand eight hundred and seventy.
Witness,
G. F. REDFERN.
FRED. R. WINDOW. (L.S.)