An Improvement in the Method of and Materials or Compound Employed in Developing Photographic Pictures or Images.
Year: 1888

page_text: Date of Application, 14th Nov., 1888
Complete Specification Left, 29th June, 1889-Accepted, 3rd Aug., 1889
PROVISIONAL SPECIFICATION.
An Improvement in the Method of and Materials or Compound
Employed in Developing Photographic Pictures or Images.
1, WILLIAM OLDHAM of 100 High Street, Eton, in the County of Buckingham,
Pharmaceutical Chemist and Optician, do hereby declare the nature of this invention
to he as follows :-
Heretofore the development of pictures or images on prepared photographic plates
has been effected by the employment of a combination of chemicals in the form of
solution or solutions, or part of the combination in the form of a solution.
According to my invention, I employ a developer in the form of Anhydrous or dry
powder contained in a bottle, by which I obtain economy, cleanliness, compactness,
and completeness, thereby obviating the necessity of carrying or keeping any chemicals
in solution.
The Anhydrous or dry powder developer, which I have found to answer well, is
prepared from the following materials, in about the proportions stated, namely,
Hydrokinone in powder, 3 parts; Sulphite of Soda in powder, 6 parts; Meta-Sulphite
of Soda in powder, 2 parts; and Bicarbonate of Soda, reduced to Carbonate
(commonly called Subcarbonate) of soda by heat or other means, or the Subcarbonate
of Soda prepared from any source, dried and reduced to powder, 16 parts.
These materials are intimately mixed, so as to form a dry powder compound, the
ingredients of which are equally diffused throughout the mass.
In use sprinkle the powder into a developing dish and add water and then
immerse the photographic plate.
I would here remark that I do not confine myself to the employment of the
materials and proportions herein, stated in the preparation of the Anhydrous or dry
powder developer, as the proportions of such materials may be somewhat varied and
other equivalent materials may be employed in lieu of one or more of those above.
mentioned.
Dated this 14th day of November 1888.
WILLIAM OLDHAM.
By Harris & Mills,
23, Southampton Buildings, Agents.
COMPLETE SPECIFICATION.
An Improvement in the Method of and Materials or Compound
Employed in Developing Photographic Pictures or Images.
I, WILLIAM OLDHAM of 100 High Street, Eton, in the County of Buckingham,
Pharmaceutical Chemist and Optician, 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 ---
Heretofore the development of pictures or images on prepared photographic plates
has been effected by the employment of a combination of chemicals in the form of
solution or solutions, or part of the combination in the form of a solution.
According to my invention, I employ a developer in the form of anhydrous or dry
powder, which may be contained as a single powder in a bottle, or may be in the
form of two powders contained in separate parcels, which latter arrangement is the
method I prefer to adopt for the reasons hereinafter given. By these means I obtain
economy, cleanliness, compactness, and completeness, and at the same time obviate the
necessity for carrying or keeping any chemicals in solution.

page_text: One form of anhydrous or dry powder developer which I have found to answer well,
is prepared from the following materials in about the proportions stated, namely,
Hydrokinoue in powder, 3 parts; Sulphite of Soda in powder, 7 parts; Meta-
Sulphite of Soda or Potash in powder, 1 parts; and Bicarbonate of Soda, reduced to
Carbonate (commonly called Sub-Carbonate of Soda by heat or other means, or the
Sub-Carbonate of Soda prepared from any source, dried and reduced to powder, 12 parts.
These materials are intimately mixed, so as to form a dry powder compound, the
ingredients of which are equally diffused throughout the mass.
In use, I sprinkle the powder into a developing dish and add water, and then
immerse the photographic plate.
I would here remark that I do not confine myself to the employment of the
materials and proportions above stated in the preparation of the anhydrous or dry.
powder developer, as the proportions of such materials may be somewhat varied, and
other equivalent materials may be employed in lieu of one or more of those above
mentioned.
In practice I prefer to prepare the developer in the form of two dry powders
contained in separate parcels, as hereinafter described, by which means the said dry
powder developer keeps in an unaltered state for an indefinite length of time, whịch
it will not do when in the form of a single powder, as in the latter case, in about two
months, the mixture loses its fresh appearance although it does not lose its qualities,
but when separated into two powders, the qualities of the developer are not impaired
by keeping and the color is quite maintained, and for many reasons, users will find
the developer when made up in two packages much more convenient than when in the
form of a single powder in a bottle, as it occupies less space and is correctly measured
out for use.
In preparing the developer in the forin of two dry powders, I form No. 1 powder of
Hydrokinone in powder, 3 parts, Sulphite of Soda in powder, 7 parts, Meta-Sulphite
of Potash in powder, 1 parts; these materials are intimately mixed and placed in a
separate parcel.
No. 2 powder consists of dried Carbonate of Soda, commonly called Sub-carbonate,
reduced to fine powder, 12 parts. These two powders are separately meted out into
the necessary quantities for developing photographic plates of different sizes, and made
into separate parcels, which are numbered or otherwise marked to indicate the size of
plate for which it is intended to be used. In use, one of each of the separately meted
out parcels of powder is sprinkled in a dish to which water is added, after.which the
photographic plate is immersed therein.
my
said
Having now particularly described and ascertained the nature of
invention, and in what manner the same is to be performed, I declare that what I
claim is ―
A dry powder developer, for developing photographic pictures or images, prepared
and used substantially as herein described.
Dain thin 30th day of June 1880