IMPROVED PROCESSES FOR THE PRODUCTION OF PHOTOGRAPHIC IMAGES CAPABLE OF BEING
Year: 1865

page_text: LETTERS PATENT to Richard Archibald Brooman, of 166, Flect Street,
in the City of London, Patent Agent, for the Invention of "IMPROVED
PROCESSES FOR THE PRODUCTION OF PHOTOGRAPHIC IMAGES CAPABLE OF BEING
Sealed the 8th September 1865, and dated the 14th March 1865.
PROVISIONAL SPECIFICATION left by the said Richard Archibald Brooman
at the Office of the Commissioners of Patents, with his Petition, on the
14th March 1865.
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
"IMPROVED PROCESSES FOR THE PRODUCTION OF PHOTOGRAPHIC IMAGES CAPABLE OF
BEING INKED WITH FATTY LNKS," to be as follows:-
The reducing action exercised by light upon neutral chromates and alkaline
bichromates mixed with solutions of gelatine, albumen, and other analogous
organic substances has been and still is applied to the production of photo;
graphic images inkable by fatty inks by the means employed by lithographers
and engravers, but the photographs hitherto produced are far from perfect.
The Inventors have sought to discover,-
1st. Whether on the one hand chromic acid salts more acid and more
complex than protochromates and bichromates, and consequently more easily

page_text: decomposable by light, and whether on the other hand bodies more capable of
reducing the oxygen of the chromates than gelatinous and albumenous solu-
tions, and others of the same class, added to the said solutions could not help
the light to transform more completely the salts of chromic acid to the state
of chromate of chromium, and thereby communicate to photographic proofs
thus generated a more complete affinity for fatty bodies intended to ink
them.
2nd. Whether soaps of silver spread over gelatinous, albumenous, gummy,
and other analogous coatings containing salts of chromic acids would not
favor the ulterior inking of photographic images by being decomposed by
light at the same time as the chromic compounds of the underlaying coatings.
The following are the results, and the Invention consists in the employment of
the processes herein-after described.
1st, alkaline trichrochromates mixed with a solution of gelatine and other sub-
stances in the same chemical group, to which have been simultaneously added
gums, acids, or salts having great affinity for oxygen, such as formic, gallic,
pyrogallic, and tartaric acids, and soluble salts formed by the same acids, either
inorganic salts also having affinity for oxygen, such as hyposulphites, sulphites,
bisulphites, hypophosphates, and phosphates have been rapidly reduced by
light and so completely that the photographic images generated by them have
acquired such an affinity for fatty bodies, and such a porosity for water, that
these same images have reproduced by inking the slightest demi-tints of the
original.
2nd, bichromate of ammonia and of bichloride of mercury, bicarbonate of
potass and of bichloride of mercury, bichromate of soda and of bichloride of
mercury, trichromate of potass and of bichloride of mercury, and trichromate
of soda and of bichloride of mèrcury used either pure or mixed with alkaline
protochromates, bichromates, and trichromates, with or without the addition
of bodies having affinity for oxygen, and added to gelatinous and other similar
organic solutions have all yielded upon paper, cardboard, stone, glass, and
ceramic ware positive images completely reduced and inkable by fatty inks
after the fashion of lithographers with a roller or pad.
3rd, the chromo-alkalino-mercurial salts above mentioned dissolved and
added to gelatinous solutions spread in thin layers upon sheets of zinc, copper,
cast iron, steel, and other metal, then impressed by light, yield after prolonged
washings by water images very well reduced and very adhering, but inkable
negatively, whence it follows that to obtain images inkable positively it is
necessary to employ positive plates. This result, the inverse of that obtained
with the same salts upon paper, cardboard, wood, stone, and ceramic ware, is

page_text: completely new. It is explainable, however, on the one hand, by the doubly
reducing action of light upon the bichloride of mercury, and upon the chromic
acid of the chromates, and on the other hand, by the action of the metals
decomposed in presence of water; the salt of mercury in all parts where the
light has not acted has not restored to the state of insoluble protochloride the
bichloride combined with the bichromates or the trichromates mixed with
the gelatinous layers.
4th, layers of gelatine, albumen, gum, and the like, with the addition of one
or other of the chromic acid salts before named, and deposited upon paper,
card, wood, stone, glass, ceramic ware, or upon metal, having been covered
after desiccation with layers of argentic soaps, then subjected to luminous
action, two superposed images are produced, one resulting from the decom-
position of the soaps of silver, the other from the reduction of the chromates
by the simultaneous effect of light. These superposed images having been
afterwards washed with cold water, and then with warm water, and subse-
quently inked by the roller or pad, became covered with fatty inks, adhesive
in all parts where the light had acted.
The proportions in which the chemicals are mixed are as follows:-I add
to a solution of gelatine (or other analogous chemical composition) containing
100 parts of gelatine, a saturated solution of potassic trichromate at 25°
Beaumé, and containing about 15 per cent. of trichromate, and from about
12 to 20 per cent. of the other salts of chromium and of mercury herein-
before specified when the said salts are used. To this first mixture are
added from 20 to 30 drops of one of the reducing agents before described,
together with 3 to 5 per cent. of gum or other analogous substance.
These mixtures and proportions may however be varied, for example, the
proportions of the salts of chromium and of the gum may be increased or
diminished according to the seasons and to the intensity of the images to be
obtained.
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 14th September 1865.
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 Fourteenth day of March, in the year of our Lord One

page_text: thousand eight hundred and sixty-five, in the twenty-eighth 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
"IMPROVED PROCESSES FOR THE PRODUCTION OF PHOTOGRAPHIC IMAGES CAPABLE OF
BEING INKED WITH FATTY INKS," (communicated to me from abroad by Cyprien
Marie Tessié du Motay and Charles Raphael Maréchal, both of Metz, France,)
upon the condition (amongst others) that I, the said Richard Archibald
Brooman, my executors or adininistrators, 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:-.
The reducing action exercised by light upon neutral chromates and alkaline
bichromates mixed with solutions of gelatine, albumen, and other analogous
organic substances has been and still is applied to the production of photo-
graphic images inkable by fatty inks by the means employed by lithographers
and engravers, but the photographs hitherto produced are far from perfect.
The Inventors have sought to discover,-
1st. Whether on the one hand chromic acid salts more acid and more com-
plex than protochromates and bichromates, and consequently more easily
decomposable by light, and whether, on the other hand, bodies more capable
of reducing the oxygen of the chromates than gelatinous and albumenous
solutions, and others of the same class, added to the said solutions could not
help the light to transform more completely the salts of chromic acid to the
state of chromate of chromium, and thereby communicate to photographic
proofs thus generated a more complete affinity for fatty bodies intended to ink
them.
2nd. Whether soaps of silver spread over gelatinous, albumenous, gummy,

page_text: and other analogous coatings containing salts of chromio acids would not favour
the ulterior inking of photographic images by being decomposed by light at
the same time as the chromic compounds of the underlaying coatings. The
following are the results, and the Invention consists in the processes herein-
after described.
Alkaline trichromates mixed with a solution of gelatine and other sub-
stances in the same chemical group, to which have been simultaneously added
gums, acids, or salts having great affinity for oxygen, such as formic, gallic,
pyrogallic, and tartaric acids, and soluble salts formed by the same acids,
either inorganic salts, also having affinity for oxygen, such as hyposulphites,
sulphites, bisulphites, hypophosphates, and phosphates have been rapidly
reduced by light, and so completely that the photographic images generated
by them have acquired such an affinity for fatty bodies, and such a porosity for
water, that these same images have reproduced by inking the slightest demi-
tints of the originals.
2nd, bichromate of ammonia and of bichloride of mercury, bicarbonate of
potass and of bichloride of mercury, bichromate of soda and of bichloride of
mercury, trichromate of potass and of bichloride of mercury, and trichromate
of soda and of bichloride of mercury, used either pure or mixed with alkaline
protochromates, bichromates, and trichromates, with or without the addition of
bodies having affinity for oxygen, and added to gelatinous and other similar
organic solutions, have all yielded upon paper, cardboard, stone, glass, and
ceramic ware positive images completely reduced and inkable by fatty inks
after the fashion of lithographers with a roller or pad.
3rd, the chromo-alkalino-mercurial salts above mentioned dissolved and
added to gelatinous solutions spread in thin layers upon sheets of zinc, copper,
cast iron, steel, and other metal, then impressed by light, yield after prolonged
washings by water images very well reduced and very adhering, but inkable
negatively, whence it follows that to obtain images inkable positively it is
necessary to employ positive plates. This result, the inverse of that obtained
with the same salts upon paper, cardboard, wood, stone, and ceramic ware, is
completely new. It is explainable, however, on the one hand, by the doubly
reducing action of light upon the bichloride of mercury, and upon the chromic
acid of the chromates, and on the other hand, by the action of the metals
decomposed in presence of water; the salts of mercury in all parts where the
light has not acted has not restored to the state of insoluble protochloride the
bichloride combined with the bichromates or the trichromates mixed with the
gelatinous layers.
4th, layers of gelatine, albumen, gum, and the like, with the addition of

page_text: one or other of the chromic acid salts before named, and deposited upon paper,
card, wood, stone, glass, ceramic ware, or upon metal, having been covered
'after desiccation with layers of argentic soaps, then subjected to luminous
action, two superposed images are produced, one resulting from the decompo-
sition of the soaps of silver, the other from the reduction of the chromates
by the simultaneous effect of light. These superposed images having been
afterwards washed with cold water, and then with warm water, and subse-
quently inked by the roller or pad, became covered with fatty inks adhesive in
all parts where the light had acted.
The proportions in which the chemicals are mixed are as follows:-I add
to a solution of gelatine (or other analogous chemical composition) containing
100 parts of gelatine a saturated solution of potassio trichromate at 25°
Beaumé, and containing about 15 per cent. of trichromate, and from about
12 to 20 per cent. of the other salts of chromium and of mercury herein-
before specified when the said salts are used. To this first mixture are added
from 20 to 30 drops of one of the reducing agents before described, together
with 3 to 5 per cent. of gum or other analogous substance. These mixtures
and proportions may however be varied, for example, the proportions of the
salts of chromium and of the gum may be increased or diminished according
to the seasons and to the intensity of the images to be obtained.
In witness whereof, I, the said Richard Archibald Brooman, have here-
unto set my hand and seal, this Fourteenth day of September, One
thousand eight hundred and sixty-five.