An Improved Preparation of Chemicals adapted to the Development of Photographic Plates and the like.
Year: 1890

page_text: Date of Application, 24th Sept., 1890
Complete Specification Left, 8th Dec., 189C-Accepted, 10th Jan., 1891
PROVISIONAL SPECIFICATION.
An Improved Preparation of Chemicals adapted to the Development
of Photographic Plates and the like.
I ABEL MCDONALD of 1 Lawn Terrace Silloth in the County of Cumberland
Photographic Engineer do hereby declare the nature of this invention to be as
follows:-
In the preparation of developers for photographic plates and the like it is necessary
to possess a number of different chemicals both in crystals and solution such as liquid
ammonia nitric acid &c. &c., which are more or less injurious to the health, this
necessitates the manipulator to have in possession a number of bottles of solution &c.
from which an accurate portion must be mixed at the time of developing; by aid of
weights and measures, this causes loss of time risk of breakage and encumbrance
when on a tour.
To dispense with the aforesaid disadvantages I purpose manufacturing a com-
bination of chemicals into one body possessing the essential properties of a first class
developer.
This I accomplish with the following chemicals and in the following manner.
I fuse together 1 part of sodium oxide 3 parts of sodium carbonate and 6 parts
of sodium sulphite or in other proportion that may from time to time be necessary.
I then form the compound into tablets or sticks of a convenient size and weight
ready for dissolving in a given quantity of water without the aid of weights or
measures.
The advantages of my invention are
1st. Being a combination of chemicals in one solid body the photographer does
not require to have in stock a number of different chemicals.
2nd. Being of a convenient size and weight it can be readily mixed at the time of
use without the aid of weights and measures by any inexperienced person.
3rd. It entirely dispenses with the burdensome practice of carrying developing
solution in bottles as it is used with dry pyrogallic acid alone, thus the entire
chemicals necessary for developing are light and can be kept in a small compass
making it an acceptable boon to tourists as well as professional photographers at
home.
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COMPLETE SPECIFICATION.
An Improved Preparation of Chemicals adapted to the Development
of Photographic Plates and the like.
ABEL MCDONALD of 1 Lawn Terrace Silloth in the County of Cun.berland
Photographic Engineer, 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 preparation of developers for photographic plates and the like, it is necessary
to possess a number of different chemicals, both in crystals and solutions such as
liquid ammonia nitric acid &c. &c. which are more or less injurious to the health, this
necessitates the manipulator to have in possession a number of bottles of solution &c.
from which an accurate portion must be mixed at the time of development by aid of
weights and measures.
This causes loss of time risk of breakage and encumbrance when on a tour.

page_text: To dispense with the aforesaid disadvantages I purpose manufacturing a com-
binatio of chemicals into one body possessing the essential properties of a first class
develover.
1
Thi accomplish with the following chemicals and in the following manner.
I fus together one part of sodium oxile, four parts of sodium carbonate and eight
parts of sodium sulphite or other proportions that may from time to time be found
necessary.
I then form the compound into tablets or sticks of a convenient size and weight,
realy for dissolving in a given quantity of water, without the aid of weights and
measures.
The advantages of my invention are:-
1st. Being a combination of chemicals in one solid body the photographer does not
require to have in stock a number of different chemicals.
2nd. Being of a convenient size and weight and soluble it can be readily mixed
at the time of use without the aid of weights or measures by an inexperienced
person.
3rdly. It entirely dispenses with the burdensome practice of having to carry
developing solution in bottles as it is used with dry pyrogallic acid alone thus the
entire chemicals necessary for developing are light and can be kept in a small compass
making it an acceptable boon to tourists as well as professional photographers at
home.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is
To manufacture a combination of sodium chemicals into a solid body substantially
as and for the purposes described.
Dated this Sixth day of December 1890.
BAILED