IMPROVE- MENTS IN PRODUCING PHOTOGRAPHIC PICTURES
Year: 1861

page_text: LETTERS PATENT to Richard Archibald Brooman, of 166, Fleet Street,
in the City of London, Patent Agent, for the Invention of "IMPROVE-
MENTS IN PRODUCING PHOTOGRAPHIC PICTURES."-A communication from
abroad by Adolphe Fargier and Nicolas Charavet. of Paris. France.
PROVISIONAL SPECIFICATION left by the said Richard Archibald Brooman
at the Office of the Commissioners of Patents, with his Petition, on the
18th April 1861.
I, RICHARD ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of
London, Patent Agent, do hereby declare the nature of the said Invention for
"IMPROVEMENTS IN PRODUCING PHOTOGRAPHIC PICTURES," (communicated to me
from abroad by Adolphe Fargier and Nicolas Charavet, of Paris, France,) to
be as follows:-
This Invention consists in obtaining by the aid of powdered coal, as here-
after fully explained, photographic pictures possessing all the gradations
of shade from black to white. The Invention is based upon the fact that
when a substance more or less translucid is sensible to the action of light
this action commences at the surface and continues gradually to the interior.
The Invention is thus carried into effect:-Upon a plane surface, such
as glass, spread a coat of gelatine holding in suspension a carbonaceous or
other powder, and made sensitive to light by bichromate of potass or other
suitable salt, dry it in the dark, and by preference upon a metal plate under

page_text: a heat which must not be allowed to exceed 212° Fahr., then place the
glass in an ordinary frame, the sensitive coating in contact with the plate
to be copied, the picture becomes formed on the surface of the coating
after an exposure of from one to four minutes to the solar rays, and after
a more prolonged exposure to diffused light according to the intensity of the
light and the sharpness of the plate. Return the glass to darkness (the
picture is not visible on being taken from the frame) and pour upon the
gelatine a coating of non-iodized collodion, next plunge the glass in hot
water, and this may be done in the light, remove the collodion from the
glass, take away the glass and the sheet of collodion floats in the water,
showing the picture which has now become visible. After a few washings
the picture is received upon a sheet of gelatinized paper, or other suitable
surface; gum or albumen may be substituted for gelatine, and instead of
collodion a sheet of prepared paper may be used, but the picture is then
reversed; the collodion may be iodized or contain different salts which will
increase its adherence. Finally, the coat of collodion may be removed from
the picture by alcoholized ether or other solvent.
The process may be modified in manner following:-Take a sheet of
paper, the thinnest possible, and made from homogeneous pulp, apply one or
more coats of the gelatinous solution herein-before referred to, dry it and
place it in the frame upon the plate, not on the gelatinized, but on the opposite
side; after an exposure to light for a longer period than directed in the
process first described a reversed picture is obtained on the surface of the
paper, which becomes detached by washings in warm water. The transparency
of the paper may be increased by rubbing oil or grease into it, and after drying
the gelatine gold beaters' skin may be used. In order also that the sheet
may remain stretched out while the gelatine is drying it may be made to
adhere to a glass or other flat surface.
A further modification is as follows:-Spread upon a glass a first coating
of the gelatinous solution, but without powdered coal, dry and expose for
a few minutes to the light, and then in the dark; apply over the first
coating a second coating with the powdered coal, allow to dry, place the
glass in the frame upon the plate, not on the gelatinized but on the opposite
side, expose to solar rays, and the picture is obtained upon glass, from which it
is removed by washings in warm water.
The three processes described are based upon the fact herein-before cited.
The action of light coagulates the gelatine and retains it on the surface of
the collodion, of the paper, or of the glass with the powdered coal.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Richard Archibald Brooman in the Great Seal Patent Office
on the 18th October 1861.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
ARCHIBALD BROOMAN, of 166, Fleet Street, in the City of London, Patent
Agent, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Eighteenth day of April, in the year of our
Lord One thousand eight hundred and sixty-one, in the twenty-fourth
year of Her reign, did, for Herself, Her heirs and successors, give and
grant unto me, the said Richard Archibald Brooman, Her special licence that
I, the said Richard Archibald Brooman, my executors, administrators, and
assigns, or such others as I, the said Richard Archibald Brooman, 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
PRODUCING PHOTOGRAPHIC PICTURES," (a communication from abroad by Adolphe
Fargier and Nicolas Charavet, of Paris, France,) upon the condition (amongst
others) that I, the said Richard Archibald Brooman, 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.
NOW KNOW YE, that I, the said Richard Archibald Brooman, do hereby
declare the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the following
statement thereof, that is to say :-
This Invention consists in obtaining by the aid of powdered coal, as here-
after fully explained, photographic pictures possessing all the gradations
of shade from black to white. The Invention is based upon the fact that
when a substance more or less translucid is sensitive to the action of light
this action commences at the surface and continues gradually to the interior.
The Invention is thus carried into effect, the materials employed being

page_text: bichromate of potash, gelatine, and powdered carbon, which are used in or
about the following proportions: In 31 cubic inches of water dissolve in
a water bath 123 grains of clear gelatine, as free from alum as possible,
perfectly pure gelatine is preferable, then crush in a mortar 15 grains of
lampblack, charcoal dust, or other suitable black, previously washed with
carbonite of soda, and then with hydrochloric acid, to remove all fatty and
resinous matters that may be present in it. It will also be well to calcine
the black to destroy all organic matter. Add a few drops of ammonia to
decompose any alum that may be contained in the gelatine, and dissolve in
the mixture about 15 grains of the bichromate of potash. The mixture
It must be
thus prepared is filtered through fine linen and is ready for use.
kept in such a temperature that it will always remain in a liquid state. To
use the preparation pour a coat of it upon a well cleaned and plane surface such
as glass, dry it, not in direct contact with the fire but by preference upon
a metal plate, care being taken that the temperature does not reach 212° Fah.
then place the glass in an ordinary frame, the sensitive coating in contact
with the plate to be copied, the picture becomes formed on the surface of
the coating after an exposure of from one to four minutes to the solar rays,
and after a more prolonged exposure to diffused light according to the inten-
sity of the light and the sharpness of the plate; return the glass to darkness
and pour upon the gelatine a coating of non-iodized collodion, next plung the
glass in hot water, and this may be done in the light, remove the collodion
from the glass, take away the glass and the sheet of collodion floats in the
water shewing the picture which has now become visible.
After a few
washings the picture is received upon a sheet of gelatinized paper or other
suitable surface. Gum or albumen may be substituted for gelatine, and
instead of collodion, a sheet of prepared paper may be used, but the picture
is then reversed; the collodion may be iodized or contain different salts, which
will increase its adherence. Finally, the coat of collodion may be removed
from the picture by alcoholized ether or other solvent.
The process may be modified in manner following:-Take a sheet of paper,
the thinnest possible, and made from homogeneous pulp, apply one or more coats
of the gelatinous solution herein-befere referred to, dry it, and place it in the
frame upon the plate, not on the gelatinized, but on the opposite side, after an
exposure to light for a longer period than directed in the process first described
a reversed picture is obtained on the surface of the paper, which becomes
detached by washings in warm. water. The transparency of the paper may be
increased by rubbing oil or grease into it, and after drying the gelatine gold

page_text: beaters' skin may be used. In order also that the sheet may remain stretched
out while the gelatine is drying it may be made to adhere to a glass or other
flat surface.
A further modification is as follows:-Spread upon a glass a first coating
of the gelatinous solution but without powdered coal, dry, and expose for a
few minutes to the light, and then in the dark; apply over the first coating
a second coating with the powdered coal, allow to dry, place the glass in the
frame upon the plate, not on the gelatinized, but on the opposite side, expose
to solar rays and the picture is obtained upon glass from which it is removed
by washings in warm water.
The three modifications of the process are based upon the fact before cited.
The action of light coagulates the gelatine and retains it on the surface of the
collodion, of the paper, or of the glass with the powdered carbon.
And having now described the nature of the said Invention, and in what
manner the same is to be performed, I declare that I do not claim the
mixture of bichromate of potash of powder and of organic substances such as
gelatine, gum, or albumen; but I claim, the several methods herein described
of producing and developing photographic pictures in order to obtain perfect
gradation of the tints or shades of the image.
In witness whereof, I, the said Richard Archibald Brooman, have
hereunto set my hand and seal, this Eighteenth day of October, One
thousand eight hundred and sixty-one.