IMPROVE- MENTS IN THE PRODUCTION OF PHOTOGRAPHIC PRINTS."
Year: 1874

page_text: LETTERS PATENT to John Robert Sawyer, of Brownlow Road, Ealing
Dene, in the County of Middlesex, for the Invention of "IMPROVE-
MENTS IN THE PRODUCTION OF PHOTOGRAPHIC PRINTS."
PROVISIONAL SPECIFICATION left by the said John Robert Sawyer at
the Office of the Commissioners of Patents, with his Petition, on
the 29th October 1874.
I, JOHN ROBERT SAWYER, of Brownlow Road, Ealing Dene, in the
County of Middlesex, do hereby declare the nature of the said Invention
for "IMPROVEMENTS IN THE PRODUCTION OF PHOTOGRAPHIC PRINTS," to be as
follows:-
It is well known that in the operation of printing with a pellicle of
gelatine and carbon or other coloring matter made sensitive to the action
of light the surface of the pellicle applied to the negative becomes
insoluble and prevents the development of the picture from the surface
of the pellicle upon which the light has acted; it becomes necessary

page_text: therefore to attach that side to some surface which shall serve as the
temporary support during the development and allow of the removal of
the paper or material upon which the pellicle is made, thus enabling the
development to be carried on from the back of the picture, which is
more or less soluble, according to the amount of the penetration of the
action of the light during exposure under the negative. This temporary
support must be of such a nature as to enable the picture to be properly
developed by immersion and washing in warm water, and yet be of such
a nature as to allow the picture when properly developed to be trans-
ferred without injury to its permanent support, the conditions required
being a surface sufficiently tenacious to hold the picture during develop-
ment, and yet sufficiently yielding to permits its transference when
completed to its final support.
:-
My Invention consists in the application of an aqueous solution of
shell, seed, or bleached lac in borax, to the surface of paper, cardboard,
metal, glass, porcelain, earthenware, or slate, and then treating the
surface with a solution consisting of a few grains to the ounce of wax
or resin, or both dissolved in benzole. This I accomplish as follows :-
When I desire to use paper I coat it (either upon a machine or by
floating or brushing) with a solution of gelatine containing about five
per cent. of chrome alum. When this is perfectly dry I coat it with a
solution made as follows:-Sixteen ounces of lac (bleached by
preference), five ounces of borax, and cight pints of water are placed in
a digester and dissolved at a high temperature. When solution is
complete, which will take from one to three hours, according to the
solubility of the lac, it is strained through cotton wool, and when cold is
ready for use. The sized paper previously named is coated with this
solution either in a machine, or by immersion, or floating, or brushing,
the object being to secure a perfectly even coating or varnish of the
solution of lac in borax. When the paper is quite dry it is treated by
rubbing the coated surface with a solution made by dissolving a few
grains of wax and resin in benzole. This is applied with a soft cloth
and afterwards polished off so as to secure an even surface of a slightly
greasy nature.
When I desire to employ cardboard I first render it waterproof by
immersion in the solution of gelatine and chrome alum, or in the lac
solution itself, or in a solution of shell lac in spirit, when dry rolling it
heavily to obtain a smooth hard surface. The lac. solution is then

page_text: applied, as previously described, and the surface finished with the benzole
solution of wax and resin for metal, glass, porcelain, eartheware, or
slate. The lac solution may be poured on and the plate dried in a hori-
zontal position in a hot closet or oven, the surface afterwards being
finished with the benzole solution. The tissue tablet or plate so prepared
I designate temporary support, and is ready for use as follows:-Having
obtained the latent image upon the gelatine and carbon pellicle, which.
I now designate tissue (and which is known commercially as autotypo
tissue), I take the temporary support, place it and the tissue bearing the
latent image under water for a few seconds, bring the two surfaces
together and press them into absolute contact with a squeczor or other
suitable instrument. The two are now laid aside for a few minutes, they
are then immersed in warm water, which allows the paper at the back
of the picture to be removed, the other surface still adhering to the
temporary support. The picture can now be developed in the usual way,.
and as the development progresses the picture begins to appear, shewn
up by the surface beneath, with all its detail and gradation of light and
shade, held perfectly together by the coating of the temporary support.
When the picture is sufficiently developed, remove to cold water, thence
to the alum bath, and thence into a bath of clean cold water. It is now.
ready for the final transfer, which is accomplished by soaking a piece of
the ordinary double transfer paper in water till the slimy condition is
attained, then bringing the surface of the picture into contact with the
prepared surface of the transfer paper under water; lift out both together,-
press into contact if necessary, hang up, and when perfectly dry the
finished picture may be peeled away from the temporary support, with
an excellent surface fit for mounting and finishing, leaving the temporary.
support fit for use on being again rubbed over with the waxing com-
pound.
"

page_text: WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of October, in the
year of our Lord One thousand eight hundred and seventy-four, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said John Robert Sawyer, Her
special licence that I, the said John Robert Sawyer, my executors,
administrators, and assigns, or such others as I, the said John Robert
Sawyer, 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
"IMPROVEMENTS IN THE PRODUCTION OF PHOTOGRAPHIC PRINTS," upon the con-
dition (amongst others) that I, the said John Robert Sawyer, 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
Scal Patent Office within six calendar months next and immediately
after the date of the said Letters Patent.
NOW KNOW YE, that I, the said John Robert Sawyer, 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 :-
It is well known that in the operation of printing with a pellicle of
gelatine and carbon or other coloring matter made sensitive to the action
of light, the surface of the pellicle applied to the negative becomes
insoluble and prevents the development of the picture from the surface
of the pollicle upon which the light has acted; it becomes necessary
therefore to attach that side to some surface which will serve as the
temporary support during the development and allow of the removal of
the paper or material upon which the pellicle is made, thus enabling the
development to be carried on from the back of the picture, which is
more or less soluble, according to the amount of the penetration of the
action of the light during exposure under the negative. This temporary
support must be of such a nature as to enable the picture to be properly
developed by immersion and washing in warm water, and yet be of such
a nature as to allow the picture when properly developed to be trans-

page_text: ferred without injury to its permanent support, the conditions required
being a surface sufficiently tenacious to hold the picture during develop-
ment, and yet sufficiently yielding to permit its transference when
completed to its final support.
My Invention consists in the preparation of a surface which becomes
adhesive whilst moist, and in that state holds the picture most thoroughly
in every variety of gradation and detail. This surface becoming con-
tractile when dry allows the developed print to leave it when mounted
upon the paper or other material on which it is destined to remain. The
material or tissue having these properties, and which I designate
temporary flexible support," I make as follows:-I take French
gelatine of the best kind, and soaking it in cold water for a few minutes
by the application of gentle heat make a solution of varying strength,
according to the amount of surface or polish which it is desired that the
finished photograph shall possess. If I desire a dull or matt surface I
make the solution of the strength of 5 per cent. or less. If I wish the
surface to be highly glazed or polished I increase the quantity of gelatine
to 10 per cent. or more. To the gelatine in solution I add as much
chrome alum is it will bear without becoming thick or ropy. This print
being variable with different samples of gelatine can only be ascertained
by experiment, but as a rule the best French gelatine made into a
solution of 5 per cent. will bear about 22 grains of chrome alum to
each ounce of dry gelatine employed a 7 per cent. about 18 grains,
and a 10 per cent. about 14 grains. Having then mixed as large a pro-
portion of chrome alum with the gelatinous solution as it will bear, I
with it coat paper, either from a continuous roll or long length, on a
machine with a trough constructed for the purpose, or by floating
separate sheets of paper for about a minute upon the solution whilst
kept warm in a shallow dish. After coating in either of these ways it'
is hung up to dry spontaneously or by moderate warmth, as may be
most convenient. It is then ready for the next operation, but before
proceeding with that I find it a great advantage to condense the material
either by passing the sheets between the plates of a rolling press or
subjecting them to the action of a powerful hydraulic press. The roll
or sheets of gelatined paper are next coated either on the machine or by
floating for one minute on a dish containing a solution made as follows:
-I dissolve by heat one pound of lac, bleached shell, or button, but by
preference the best button lac, in 5 quarts of water by adding six ounces of

page_text: borax and one ounce of sub-carbonate of soda. This may be effected by
boiling the ingredients together for some time, but I much prefer the
following method:-Into a stout cast-iron vessel, which can be entirely
closed except a safety valve, place the water having the borax and soda in
solution, then put in the button lac, and raise the temperature to con- |
siderably above the ordinary boiling point; in 2 or 3 hours the solution
will be complete, and the fluid should be strained through tow or cotton
wool whilst still hot. When cool it is ready for use, and may be placed in
the trough of the coating machine or placed in a shallow dish and the
gelatine coated paper carefully floated for about a minute upon its
surface; the tissue is then hung up to dry either spontaneously or by
moderate warmth, and the sheets are then milled by being passed
through a rolling press betweon plates of polished metal.
The next operation consists in making the surface somewhat repellent
to water by rubbing it over with a solution of resin in turpentine. This
is prepared as follows:-To one pint of pure spirits of turpentine put
half an ounce of resin, adding 10 to 20 grains of pure white wax. When
dissolved it is filtered and ready for use. This preparation is to be rubbed
lightly over the surface of the tissue with a piece of soft flannel and
then rubbed off as completely as possible with a second piece, and after
remaining for a few minutes to allow of the complete evaporation of the
turpentine it is ready for use as a "temporary flexible support." Its
employment is as follows:-After the carbon picture is printed I take a
piece of the "temporary support" cut to any size larger than the picture
to be developed, and immerse both together in cold water till the tissue
bearing the picture has become perfectly pliant. The prepared surface
of the support is now brought into contact with the surface of the print
under water, and avoiding air bubbles. Both are lifted out together, and
the adherent sheets either hung up in the air or laid between bibulous
paper for a space which may vary from ten minutes to some hours,
according to convenience, but at the expiration of 10 minutes the
development may be proceeded with by immersing the adherent sheets
in warm water at a temperature of 100 to 120 degrees Fahrenheit. In
a few seconds the oozing out of the gelatine pigment at the edges is an
indication that the paper at the back of the picture can be skinned off
and the development proceeded with in the usual manner by laving the
print with the warm water or allowing it to develope spontaneously by
placing it face downwards and allowing it to remain for some time. The

page_text: development being completed, the print is rinsed in cold water, then
placed in a solution of alum of the strength of one per cent. In this it
is allowed to remain for 10 minutes; it is then placed in cold water and
is ready for transfer to its final support. This is accomplished by bringing
the surface of the print into contact under water with the surface of the
material upon which it is desired to remain. This may be either paper
prepared with insoluble albumen, or gelatine, or canvas, wood, ivory,
glass, or any material the surface of which can be prepared with a
material having a sufficiently adhesive preparation to hold the print
thoroughly. When the surfaces so put together, as described, are
perfectly dry the temporary support may be stripped from the finished
picture with the greatest care, and will be ready for use again after being
rubbed over with a little of the resinous compound previously named in
the manner already described.
If the exposure to light has been well timed and the development
properly accomplished, the finished print will leave the temporary support
quite perfect, with all its gradation of light and shade preserved and with
all the crisp definition that the negative will afford, and the surface of the
print will be in accordance with the strength of the gelatine employed.
I am quite aware that a solution of lac in ammonia has been used as
a coating for paper to be used as a temporary support by Mr. J. R. John-
son, and that a solution of wax, resin, and turpentine has been suggested
for rubbing over the surfaces of both tissue and temporary supports;
but I claim as my Invention the combination of insoluble gelatine, as
described, with lac and its analogues to form a bed or "couche" in
which the detail of the picture is held whilst in a moist condition and
during the process of development. The advanges of employing this
material I believe to be,―
First. The perfect ease with which the primary adhesion is made.

page_text: Fifth. The purity of surface and the crispness of detail combined with
the perfect gradation of light and shade incident to this method of pro-
ducing prints in permanent pigments.
In witness whereof, I, the said John Robert Sawyer, have here-
unto set my hand and seal, this Twenty-fourth day of April, in
the year of our Lord One thousand eight hundred and seventy-five.