Improvements in the Preparation of Argentiferous Sensitive Surfaces for Photographic Purposes.
Year: 1898

page_text: Date of Application, 19th May, 1898
Complete Specification Left, 18th Mar., 1899-Accepted, 29th Apr., 1899
PROVISIONAL SPECIFICATION.
Improvements in the Preparation of Argentiferous Sensitive Surfaces
for Photographic Purposes.
I, PIERRE MERCIER, of 95, Rue Lemercier, Paris, France, Pharmaceutical
Chemist, do hereby declare the nature of this invention to be as follows:-
My invention relates to the preparation of argentiferous sensitive surfaces
capable of bearing a longer exposure to the light than heretofore, such surfaces
whether under the form of plates, paper or films and whether utilized for positives
or negatives producing photographic images by the aid of suitable developing
means. A further object of my said invention is to obtain more vivid images than
heretofore when the exposure has been inaccurate and especially when it has been
too prolonged.
My invention consists in adding to the emulsion of argentiferous salts certain
chemicals which I classify under the headings or groups A, and B, the latter com-
prising two subdivisions each.
Group A, comprises:
1. Arsenical and antimonial salts mixed with an organic salt such as a citrate
or a tartrate. I use preferably tartrate of antimony and potash.
2. Morphia, codein, their salts, and their derivatives.
To utilize the substances belonging to this group A, I make a solution containing
from 1 to 3 grammes of the substance selected per 100 grammes of water and
immerse therein the sensitive surface or film for a period of about two minutes
after which the same is allowed to dry. This treatment is preferably carried on
before exposure, it may take place after exposure but it must precede the develop-
ing stage. The developing means should preferably contain hydroquinone mixed
with sulphite and carbonate of soda to which I add bromide of potassium when
the exposure has lasted too long.
Group B, comprises:
1. The active substances forming the base of alkaline developing means such as
hydroquinone, metol, ortol, amidol, pyrogallic acid, paramido-phenol, pyroca-
techine, glycine, resorcin, and the like to which may be added apomorphia, apocodein
and eserin or physostigmin, these substances being used in their normal i.e. un-
oxidized state.
In utilizing the above substances I may proceed as for those of group A, but it
is preferable to use weaker solutions containing about 10 centigrammes of one of
these active substances per 100 grammes of water.
2. The substances mentioned in the above paragraph in an oxidized state and.
in smaller doses. I prefer for instance to use, particularly before exposure, a
solution of 1 centigramme of oxidized amidol in 100 grammes of water.
Instead of using in the treatment hereinbefore set forth, sensitive plates, paper

page_text: or films prepared beforehand i.e. such as they are found in commerce and of im-
mersing them in the solution of the substances aforesaid, I may add these sub-
stances to the argentiferous emulsion directly i.e. before spreading the same over
a glass plate, a paper sheet or a film.
Dated this 10th S 1000
DE KATOW & Co.,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Preparation of Argentiferous Sensitive Surfaces
for Photographic Purposes.
I, PIERRE MERCIER, of 95, Rue Lemercier, Paris, France, Pharmaceutical
Chemist, do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by the
following statement;-
My invention relates to the preparation of argentiferous sensitive surfaces
capable of bearing a longer exposure to the light than heretofore, such surfaces
whether under the form of plates, paper or films and whether utilized for positives
or negatives producing photographic images by the aid of suitable developing
means. A further object of my said invention is to obtain more vivid images than
heretofore when the exposure has been inaccurate and especially when it has lasted
too long. My invention consists in adding to the emulsion of argentiferous salts
one or more chemicals which I classify under the headings or groups A and B,
the latter comprising two sub-divisions each.
Group A, comprises:-
1. Antimonial salts mixed with an organic salt such as a citrate or a tartrate.
I use preferably tartar emetic, i.e., tartrate of antimony and potash.
2. Morphia, codein, their salts and derivatives. To utilize the substances
belonging to this group A, I prepare a solution containing from 1 to 3 grammes of
the substance selected per 100 gr. of water and I immerse therein the sensitive
surfaces or film for a period of about two minutes after which the same is violently
shaken in order to expel the excess of liquid-which would otherwise produce
stains and is finally allowed to dry. This treatment is preferably carried out
before exposure. It may however also take place after exposure, but it must always
precede the developing stage.
The developing means used should preferably contain hydroquinone mixed with
sulphite and carbonate of soda to which I add a small quantity of an alkaline
bromide-such as usually practised when the exposure has lasted too long.
Group B, comprises:-
1. The active substances forming the base of alkaline developing means such
as hydroquinone, metol, ortol, amidol, pyrogallic acid, paramido-phenol, pyroca-
techine, glycine, resorcin and the like to which may be added apomorphia, apocodein
and eserin or physostigmin; these substances being kept in their normal or un-
oxidized state by the addition of a small quantity of an acid-such as acetic acid-
or of an alkaline sulphite.
I am aware that several of the substances hereinbefore mentioned have already
been used in addition to the argentiferous emulsion for photographic sensitive
plates but in such cases this addition had not for its object to aid in the develop-

page_text: pyrogallic acid, ortol and the like, these substances being oxidized by allowing
their solutions to be colored by the action of air, substantially as herein described.
Tated this 17th day of March 1899.
DE KATOW & Co.,
Agents for the Applicant.