Improvements in Photographic Developers.
Year: 1893

page_text: Date of Application, 16th June, 1893
Complete Specification Left, 14th Mar., 1894-Accepted, 21st Apr., 1894
PROVISIONAL SPECIFICATION.
[Communicated from abroad by THE ACTIEN GESELLSCHAFT FÜR ANILIN
FABRIKATION, of Berlin, in the Empire of Germany, Chemical Manu-
facturers.]
Improvements in Photographic Developers.
I, CHARLES DENTON ABEL of No. 28 Southampton Buildings, Chancery Lane
in the County of London, Consulting Engineer and Chartered Patent Agent, do
hereby declare the nature of this invention to be as follows:-
In the German Patent No. 46915 (expired) attention was drawn to the developing
properties of certain para-diamines of the aromatic series. These products,
however, could not be generally applied for developing purposes, because the use of
free caustic alkalies in the developing process was necessary in order to obtain
good images. For this reason, these para-diamines have, in photographic practice,
been superseded by substances which can be employed as developers with the
aid of carbonates or sulphites of alkalies, or which require, as for instance
in the case of paraamidophenol, only the quantity of caustic alkali necessary to
form phenolates.
My foreign correspondents have now discovered that by introducing further
substituting groups, viz. the amido or hydroxyl-group into the benzene-nucleus of the
paradiamines above referred to their developing properties are enhanced to such
degree, that the products obtained may be used with satisfactory results in the
presence of carbonates or sulphites of alkalies. They may even be employed in.
combination with salts having acid-reaction, as for instance bisulphites.
Thus satisfactory results have been obtained by employing, for instance, the
following products as developers.
Amido-paraphenylendiamine (triamido-benzene; Beilstein, II. Ed. Vol. III.
page 1088).
Oxy-paraphenylendiamine (obtained by reducing the p-dinitrophenol (y) 1:3 : 6
mentioned in Beilstein II. Ed. Vol. II. page 445).
-
Amido-paratoluylendiamine (obtained by the reduction of such colouring matters
as are derived from a diazo-compound and toluylendiamine 1: 2: 4).
The following may serve as an example of the production of a developing solution
according to this invention.
In about 1000 cub. cent. of water 100 gr. sulphite of soda are dissolved and
10 gr. of hydrochloride of amido-para-toluylendiamine are then added.
The composition of the developing solutions, in respect of the quantities of the
substances employed, may be varied in many ways; moreover, for the salts herein
mentioned as being added to the developing substance, equivalent products may be
substituted, the above example of process being generally followed.
Dated this 16th day of June 1893.
ABEL & IMRAY,
Agents for the Applicant.

page_text: Improvements in Photographic Developers.
I, CHARLES DENTON ABEL, of No. 28 Southampton Buildings, Chancery Lane,
in the County of London, Consulting Engineer and Chartered Patent Agent, 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:-
In the German Patent No. 46915 (expired) attention was drawn to the developing
properties of certain para-diamines of the aromatic series.
These products, however, could not be generally applied for developing purposes,
because the use of free caustic alkalies in the developing process was necessary in
order to obtain good images.
For this reason, these paradiamines have in photographic practice, being superseded
by substances which can be employed as developers with the aid of carbonates or
sulphites of alkalies, or which require, as for instance in the case of paraamidophenol,
only the quantity of caustic alkali necessary to form phenolates.
My foreign correspondents have now discovered that by introducing further
substituting groups, viz., the amido or hydroxyl group into the benzene-nucleus of
the paradiamines above referred to their developing properties are enhanced to such
degree, that the products obtained may be used with satisfactory results in the
presence of carbonates or sulphites of alkalies. They may even be employed in
combination with salts having acid reaction, as for instance bisulphites.
Thus satisfactory results have been obtained by employing, for instance, the
following products as developers :
Amido-paraphenylendiamine (triamido-benzene; Beilstein II. Ed. Vol. III.
page 1088).
Oxy-paraphenylendiamine (obtained by reducing the p-dinitrophenol (y) 1:3:6
mentioned in Beilstein II. Ed. Vol. II. page 445).
Amido-paratoluylendiamine (obtained by the reduction of such colouring matters
as are derived from a diazo compound and toluylendiamine 1: 2: 4).
The following may serve as an example of the production of a developing solution
according to this invention.
In about 1000 cub. cent. of water 100 gr. sulphite of soda are dissolved and
10 gr. of hydrochloride of amido-para-toluylen-diamine are then added.
The composition of the developing solutions in respect of the quantities of the
substances employed, may be varied in many ways; moreover, for the salts herein
mentioned as being added to the developing substance, equivalent products may be
substituted the above example of process being generally followed.
Having now particularly described and ascertained the nature of this inven
tion and in what manner the same is to be performed, I declare that what I
claim is :
A photographic developer produced substantially as described from amidopara-
phenylendiamine, oxyparaphenylendiamine or amido paratoluylendiamine.
Dated this 14th day of March 1894.
ABEL & IMRAY,
Agents for the Applicant.