AN IMPROVED PROCESS OF TAKING PHOTOGRAPHIC PICTURES UPON GLASS, AND ALSO OF BEAUTIFYING AND PRESERVING THE SAME
Year: 1854

page_text: LETTERS PATENT to James A. Cutting, of Boston, in the United States
of America, Photographer, for the Invention of "AN IMPROVED PROCESS
OF TAKING PHOTOGRAPHIC PICTURES UPON GLASS, AND ALSO OF BEAUTIFYING AND
PRESERVING THE SAME."
Sealed the 20th October 1854, and dated the 26th July 1854.
PROVISIONAL SPECIFICATION left by the said James A. Cutting at the
Office of the Commissioners of Patents, with his Petition, on the 26th
July 1854.
I, JAMES A. CUTTING, of Boston, in the United States of America,
Photographer, do hereby declare the nature of the said Invention for "Ax
IMPROVED PROCESS OF TAKING PHOTOGRAPHIC PICTURES UPON GLASS, AND ALSO OF
BEAUTIFYING AND PRESERVING THE SAME," to be as follows:-
My improved process has reference to the art of taking pictures photo-
graphically on a film of collodion upon the surface of a sheet of glass, the
collodion being suitably prepared for the purpose.
The first part of my Invention consists in the use of alcohol, for the purpose
of depriving the gun cotton, of which the collodion is made, of its moisture after
it has been washed, to free it from the acids used in its manufacture.
After being subjected to the alcohol, the cotton is immersed in the mixture
in which it is to be dissolved, for the purpose of forming the collodion. This
mixture is composed of sulphuric aether and alcohol. The collodion thus

page_text: formed is allowed to remain until it has settled perfectly clear. It is then
decanted, and iodide of potassium dissolved in alcohol is added thereto. After
being well shaken, refined gum camphor is added to the mixture. The object
of the camphor is to increase the vigor and distinctness of delineation of the
positive pictures, and particularly of the half tints; it also greatly increases the
beauty of the picture, by giving a fineness of deposit not heretofore. attained by
any other means. The use of the gum camphor in the manner above described
forms the second branch of my Invention. The collodion is then applied to
the surface of the glass in the following manner :-The plate of glass being
held horizontally, a portion of the collodion is poured upon it, and it is then
inclined in different directions, so as to cause the collodion to flow over its
whole surface, upon which it forms a colorless transparent film. The excess
of collodion is allowed to run off, and the glass, being still held horizontally, is
inclined to one side and the other, until the collodion becomes partially thickened
or set. When this, has taken place, and before, it is. dry, it is rinsed in a
solution of crystallized nitrate of silver. The film is thus impregnated with
iodide of silver, and after remaining in this bath a sufficient length of time
for the ether to escape from the collodion, the plate is ready to be placed
in the camera. After being exposed a sufficient length of time in the camera
it is taken to a dark room, where the latent picture is developed, by the appli-
cation of a solution of protosulphite of iron, acetic acid, and nitric acid. The
plate is next washed in clean soft water, and the remaining iodide of silver is
dissolved from the collodion film by a solution of hyposulphite of soda, after
which the picture is entirely cleansed of the hyposulphite solution by washing
as before in soft water. The picture is then dried, either in the open air or
by the aid of a gentle heat, and the process is completed.
To permanently improve the beauty of the pictures, and to deprive them of a
bluish, bazy, indistinct look, is the object of my third improvement. This I
effect as follows:-A second plate of glass is prepared of the same size as that
which carries the picture, and is thoroughly cleansed; the picture plate is then
held horizontally, the picture side uppermost. Balsam of fir is then applied in
a line along one edge of the glass, and one edge of the secondary plate is then
applied to the edge of the first, which contains the balsam. The two plates
are then pressed gradually together, by which the balsam is caused to flow
entirely across the picture towards the opposite edge, and the air is effectually
excluded from between the plates; the superabundant balsam is then removed
by pressing the glasses together, and a thin coating of it only is left upon the
surface of the picture.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James A. Cutting in the Great Seal Patent Office on the
22nd January 1855.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
A. CUTTING, of Boston, in the United States of America, Photographer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-sixth day of July, in the year of our Lord
One thousand eight hundred and fifty-four, in the eighteenth year of Her
reign, lid, for Herself, Her heirs and successors, give and grant unto me,
the said James A. Cutting, Her special license that I, tho said James
A. Cutting, my executors, administrators, and assigns, or such others as I,
the said James A. Cutting, 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 OF TAKING PHOTOGRAPHIC PICTURES UPON GLASS, AND ALSO OF
BEAUTIFYING AND PRESERVING THE SAME," upon the condition (amongst others).
that I, the said James A. Cutting, by an instrument in writing under my
hand and seal, 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.
NOW KNOW YE, that I, the said James A. Cutting, 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):-
This Invention consists in an improved process of taking photographic
pictures upon glass, and also of beautifying and preserving the same, which
process I have styled "ambrotype." My improved process has reference to
the art of taking pictures photographically on a film of collodion upon the
surface of a sheet of glass, the collodion being suitably prepared for the purpose
By the use of the said process, the beauty and permanency of such pictures are
greatly increased, and I have on this account styled the process "ambrotype,"
from the Greek word ambrotos, immortal.
The first part of my Invention consists in the use of alcohol, for the purpose

page_text: of depriving the gun cotton, of which the collodion is made, of its moisture after
it has been washed, to free it from the acids used in its manufacture.
It has been found that where gun cotton has been exposed to the action of
the atmosphere for the purpose of drying it, the sensitiveness of the collodion
prepared from it is sensibly diminished. By the use of alcohol it may be
deprived of its moisture after being washed, without exposure to the air, and
without the consequent deterioration of its sensitiveness. This part of my pro-
ccss I conduct as follows:-So soon as the cotton has been sufficiently exposed
to the acids and has been thoroughly washed; it is plunged into strong alcohol,
which effectually deprives it of the water which it contains, without exposing
it to the atmosphere for the purpose. From this alcohol it is taken imme-
diately to the mixture in which it is to be dissolved for the purpose of forming
the collodion. This mixturo consists of 10 parts of sulphuric æther and 6 of
alcohol, or thereabouts. The collodion thus formed is allowed to remain until
it has settled perfectly clear, which usually requires about 24 hours. It is
then decanted, and to every pint is added 80 grains of iodide of potas
sium dissolved in alcohol. It is then well shaken, and 32 grains of refined
gum camphor is added to each pint of the collodion, and after it has again
settled it is fit for use. The object of the camphor is to increase the vigor
and distinctiveness of delineation of the positive pictures, and particularly of
the half tints. It also greatly increases the beauty of the picture, by giving a
fineness of deposit not heretofore attained by any other means. The use of the
gum camphor in the manner above described forms the second branch of my
Invention. The collodion is then applied to the surface of the glass in the
following manner :-
The plate of glass being held horizontally, a portion of the collodion is
poured upon it, and it is then inclined in different directions, so as to cause the
collodion to flow over its whole surface, upon which it forms a colorless trans-
parent film; the excess of collodion is then allowed to run off, and the glass,
being still held horizontally, is inclined to one side and the other, until the
collodion becomes partially thickened or set. When this has taken place, and
before it is dry, it is rinsed in a solution of crystallized nitrate of silver, of
a strength of 40 grains to the ounce of water; the film is thus impregnated
with iodide of silver, and after remaining in this bath a sufficient length of
time for the æther to escape from the collodion, the plate is ready to be placed
in the camera. After being exposed a sufficient length of time in the camera,
it is taken to a dark room, where the latent picture is developed, by the
application of a solution of protosulphite of iron, acetic acid, and nitric
acid, in about the following proportions:-1 quart of soft water, 1 ounce

page_text: protosulphite of iron, 32 drachms No. 8 acetic acid, 1 drachm nitric acid.
These exact. proportions are not rigid, but I have found them to be sufficient
for the purpose of developing the picture. After this is accomplished it is
washed in clean soft water, and then the remaining iodide of silver is dissolved
from the collodion film by a solution of hyposulphite of soda, after which the
picture is entirely cleansed of the hyposulphite solution by washing as before in
soft water. The picture is then dried, either in the open air or by the aid of a
gentle heat, and the process is completed.
To permanently improve the beauty of the pictures, and to deprive them of
a bluish, hazy, indistinct look, is the object of my third improvement; which
consists in the application of a coating of balsam of fir to the surface of the
glass upon which the picture is made, the balsam being confined to the picture
plate by a secondary plate of glass, which is applied to the picture plate in
a manner which will now be described, and which hermetically seals up the
picture and protects it from every and any injury not sufficient to fracture the
glasses themselves. This part of the process will now be described.
3
A second plate of glass is prepared of the same size as that which carries
the picture, and is thoroughly cleansed; the picture plate is then held hori-
zontally, the picture side uppermost. The balsam is then applied in
line along one edge of the glass, and one edge of the secondary plato is
then applied to the edge of the first, which contains the balsam. The two
plates are then pressed gradually together, by which the balsam is caused
to flow entirely across the picture towards the opposite edge, and the
air is effectually excluded from between the plates. The superabundant
balsam is then removed by pressing the glasses together, and a thin coating
of it only is left upon the surface of the picture. The beauty and distinct-
ness of the pictures are greatly enhanced by this application, the finer lines
as well as the dark portions and shadows being rendered far more distinct,
and the most minute delineations being brought out and made visible, while
the application of the second plate of glass secures the whole from the action
of air, moisture, and dust.
What I claim as my Invention, and desire to secure by Letters Patent,
is,―
1st, the method herein described of depriving the gun cotton of its
moisture by the use of alchohol, whereby the sensitiveness of the collodion
prepared therefrom is preserved unimpaired.
2d, the use of gum camphor in the preparation of collodion for the purpose
set forth.
3d, I am aware of the previous use of balsam for the purpose of cementing

page_text: together lenses, and also of securing microscopic objects, and I therefore lay
claim to no such use; but what I do claim, and desire to secure by Letters
Patent, is, the application of the balsam to the surface of photographic pictures
upon glass, in combination with the method herein described of protecting
and securing the same by means of the additional plate of glass, as set forth.
In witness whereof, I, the said James A. Cutting, have hereunto set my
hand and seal, this 22d day of December, in the year of our Lord
1854.
J. A. CUTTING. (L.S.)
HENRY B. OSGOOD.
J. A. CUTTING. (L.S.)