Improvements in Producing Photographic Prints.
Year: 1893

page_text: Date of Application, 28th Dec., 1893
Complete Specification Left, 27th Sept., 1894-Accepted, 27th Oct., 1894
PROVISIONAL SPECIFICATION.
Improvements in Producing Photographic Prints.
I, JAMES PACKHAM, of 16, Katherine Street, Croydon in the County of
Surrey, Manufacturer, do hereby declare the nature of this invention to be as
follows:-
My invention relates to the production of warm or pleasantly tinted photographic
prints that have firstly been produced in the ordinary manner by the action of light
upon the salts of platinum, or platinum salts in combination with other metallic
salts.
According to my invention I produce varying coloured tones upon the ground-
work formed by such first prints by a permanent deposition of vegetable tinctorial
matter, such deposition being brought about by the action of a solution of vegetable
dye-stuffs beated to the required temperature.
The tinctorial agents 1 prefer to employ may consist of tannin, cutch or catechu
or its products or derivatives or a combination of these organic matters with other
vegetable dye materials as, for instance, barks of various kinds, sumac or madder
either alone or in combination with deoxidizing agents.
The platinum print as before described is first steeped in a heated infusion or
decoction of one or more of the above substances at a temperature varying from
say 100 Fahrenheit upwards as shall be governed by the nature of the dyeing
material employed and for such period of time as may be necessary to arrive at the
gradation of colour required. If upon removal from the dyeing bath the whites
and high lights are found to be degraded by absorption of the tinctorial matter
which has been employed, they can be brightened by the process known as clearing
i.e. by submitting them to the action of a soap bath or soap and bran bath, acid
bath or the like.
Dated the 28th day of December 1893.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Producing Photographic Prints.
1, JAMES PACKIIAM, of 16, Katharine Street, Croydon, in the County of
Surrey, Manufacturer, 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 production of warm or pleasantly tinted photographic
prints that have been previously produced by the ordinary process of photographic
printing by the action of light on the salts of platinum, or platinum salts in
combination with other metallic salts.
According to my invention 1 produce varying coloured tones upon the ground-
work of prints as above described by a permanent deposition of vegetable tinctorial
matter, such deposition being brought about by the action of a solution of vegetable
dye-stuffs which may or may not be heated.
Several tinctorial agents may be employed to produce the depositions described
above but those which I prefer to employ when sepia or brown tints are desired, consist

page_text: of tannin, cutch or catechu or their products or derivatives or a combination of
these organic matters with other vegetable dye materials as, for instance, barks of
various kinds, sumac or madder either alone or in combination with deoxidizing
agents.
In carrying out this process care must be taken that any examination, and
changing and handling of the paper and prints is carried out in absolutely
non-actinic light so as to retain the high lights in their greatest purity.
The developer used for platinum prints materially affects the resultant tint
produced by my process; varying results may therefore be obtained by employing
a neutral acid or an alkaline developer, or a developer in combination with organic
matters as, for instance, sugar or glucose.
The platinum printing paper may be allowed to become what is known as stale,
i.e., it may be allowed to be freely acted upon by the atmosphere either before or
after printing with advantage to the resulting tints where varying results are
desired; such exposure may vary from hours to days but in all cases the paper
must be carefully shielded from the action of light. Other variations in the process
of development of the platinum paper will also produce varying results at the will
of the operator such as by using a very dilute or strong developer and employing
it at varying temperatures.
To produce the deposition of the tinting substance by what I will call the hot
process I proceed as follows:-I lay the print, previously soaked in distilled water,
in a porcelain developing dish having a perforated false bottom or tray which
serves to prevent the print from falling to the bottom of the dish. I next take a
porcelain dish containing, say, twenty fluid ounces of pure water (distilled) at a
temperature of 120° to 130° Fabreuheit and dissolve therein from ten to thirty
grains of the tinctorial matter which I intend to employ, say, cutch or terra-
japonica, an extract of uncaria-gambir which has been previously reduced to a fine
powder stirring with a clean glass rod till dissolved. This solution is now poured
over the print in the developing dish, the latter being slightly rocked to keep the
fluid in motion, and the temperature of the solution maintained at from 115° to
130° Fahrenheit until such time as the desired depth of tone is obtained. The
print is then well washed with plain water for two or three minutes, pressed between
porous paper and hung up to dry.
Varying results are obtained by keeping the tinctorial hath neutral or very
slightly alkaline; if alkaline, the tint obtained will be warmer in proportion to the
quantity employed at the expense of the high lights. It is sometimes desirable to
employ one or two grains of oxalate of potass or sulphate of alumina to each pint
of water when deep well water or water containing lime is employed.
Small proportions of other tinctorial matters may with advantage be introduced
producing varying results.
In carrying out what I will call the cold process, I first prepare a strong
decoction or infusion of the tinctorial matter to be used as, for instance, cutch or
catechu by boiling say one hundred and fifty grains of the tinctorial substance, in
five or six ounces of water until dissolved; from twenty to sixty minims of this
strong preparation is then added to one pint of water, and the print to be toned is
immersed in this liquid until the desired tint is secured which will be in from three
to four or more hours.
Some papers or prints during the above processes may become somewhat
degraded in the whites; this may be rectified by treatment in a soap bath
containing 100 to 150 grains of pure soap to each forty ounces of water, and heated
to a temperature of from 200° to 212° Fahrenheit.
The high lights are sometimes brightened by submitting the prints to the action
of acid preferably acetic acid in a very dilute form, say, thirty to sixty minims to
the pint.
When quite dry if the prints require brightening I sometimes treat them in a
bath of very dilute spirit varnish.

page_text: 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 :-
1. The production of varying tones upon photographic prints obtained by the
action of light upon the salts of platinum or platinum salts in combination with
other metallic salts by the permanent deposition upon such prints of vegetable
tinctorial matter, substantially as described.
2. In the production of photographic prints obtained by the action of light upon
the salts of platinum or platinum salts in combination with other metallic salts the
use of vegetable tinctorial substances such as cutch, catechu, terra-japonica or the
like, substantially in the manner described.
3. Toning photographic prints substantially in the manner hereinbefore
described.
4. Photographic prints toned substantially in the manner hereinbefore described.
Dated the 27th day of September 1894.
G. F. REDFERN & Co.,
4, South Street, Finsbury, London, Agents for the Applicant.