Improved Means of Obtaining Photographs in Relief in Gold, Silver, and other Materials.
Year: 1895

page_text: Date of Application, 24th Aug., 1895
Complete Specification Left, 26th May, 1896-Accepted, 24th Aug., 1896
PROVISIONAL SPECIFICATION.
Improved Means of Obtaining Photographs in Relief in Gold,
Silver, and other Materials.
ALBERT HILL Manager of The Cresco-Fylma Company 10 Palmer Crescent,
Kingston-on-Thames and ALFRED ALLEN BARRATT Clerk in Holy Orders,
Claygate Vicarage both in the County of Surrey do hereby declare the nature of
this invention to be as follows:-
The object of our invention is to provide means by which photographs may be
produced in relief by photographic means.
Advantage is taken of the readiness of bi-chromatised gelatine to swell in
proportion to the amount of water absorbed when exposed to the action of light.
In this process however the effect is to obtain a great expansion of the film from
which plaster casts may be taken, and electrotypes reproduced which may be
plated, or left in the original metal.
If however an ordinary photograph is used false relief occurs, owing to the fact
that photographic negatives take notice of color as well as modelling, this causes
false relief, for instance in a portrait the hair if dark would recede instead of
following the contour of the head.
This we correct by painting such portions that should advance on the photo-
graphic print with white pigment where it should advance, and black where it
should recede, and from this retouched photograph a negative is taken which is
printed on bi-chromatised gelatine or we may print from a transparency positive
instead of a negative which would when swelled and cast give a positive portrait and
work up the cast, in plaster or other material by hand.
The method of obtaining a very high relief is by the following procedure: the
gelatine when fully soaked in water after exposure through the negative, is
plunged into an acid bath and transferred to water. As the gelatine is firmly
affixed to its support it cannot expand laterally, and thus the expansion causes the
relief to be very much greater.
Dated this 24th day of August 1895
ALBERT HILL.
ALFRED ALLEN BARRATT.
COMPLETE SPECIFICATION.
Improved Means of Obtaining Photographs in Relief in Gold,
Silver, and other Materials.
ALBERT HILL 10 Palmer Crescent, Kingston-on-Thames Manager of The
Cresco-Fylma Co. Limited ALFRED ALLEN BARRATT Clerk in Holy Orders
Claygate both in the County of Surrey, 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 :—
This invention relates to the making of photographs in true relief, either in
plaster or other plastic material, or in metal by electro-depositing.
This process in the first stage depends on the well known action of light on
Price &d

page_text: bi-chromated gelatine, in rendering it insoluble and incapable of absorbing water,
and is to obtain a simple method of obtaining higher relief, and also, in the
case of portraiture, to correct the false modelling which in most cases is present.
In the case of side lit portraits with black backgrounds no preparation of the
negative is necessary, nor from copies of wash drawings where the background is
the darkest part.
In the case of an ordinary portrait false modelling may occur, as light in this
process takes more note of colour than form, for instance a portrait in which the
hair is dark; the modelling of the face would be rendered correctly, but the hair
would appear in the relief, to sink into the head; and the background if light in
color, would not recede sufficiently to throw the head into high relief.
To overcome this difficulty the background is painted on a print from the
negative, with black pigment, and the lights on the hair accentered with a white
pigment. An alternative is to make a thin negative, intensify with uranium; and
reduce where necessary with strong ammonia.
The method we prefer to work is to coat a piece of plate glass (which has been
well rubbed with talc,) with gelatine, to which may be added proportions of sugar
and citric acid to render the gelatine flexible; this is dried gradually to prevent
reticulation. The mixture when dry is stripped from the glass, and is then
sensitized in a solution of bi-chromate of potash (preferably 2 per cent.).
It is then exposed to the action of light under the negative, the gelatine being
flexible can be readily examined to watch the progress of printing.
When sufficiently printed it is firmly cemented to glass, with an adhesive which
swells in the same proportion as the gelatine. We prefer the use of isinglass
dissolved in weak acetic acid, to which is added a small proportion of celluloid
dissolved in amyl acetate.
The plate thus formed is soaked in water, and the gelatine will swell where not
acted on by light, and a photograph in very low relief in gelatine is obtained.
When all the bi-chromate is soaked out, the gelatine relief is plunged into weak
acid, preferably citric acid, in the proportion of one part of citric acid to six of
water by weight, or citric acid may be well rubbed into the surface, and is then
transferred to cold water.
The gelatine not being able to swell laterally, owing to its being cemented to
glass, expands vertically, but only when still absorbant to water; when the
gelatine has been acted on by the light the acid will not penetrate. The increase
by this treatment is from two to four times the relief originally gained.
From the swollen gelatine thus obtained plaster casts may be taken, or copper
may be deposited direct if the surface is rendered conductive by the use of any of
the well known agents, such as bi-sulphide of carbon and phosphorus followed by
nitrate of silver solution.
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 what I claim is
I. The correction of the print or negative as hereinbefore described, or by
retouching on the negative.
II. The vertical expansion of a gelatine relief, by means of an acid, preferably
citric, as before described.
III. Photographs in metal, or plastic material from gelatine reliefs prepared as
herein before described.
Dated this 23rd of Mar 1806
ALBERT HILL.
ALFRED ALLEN BARRATT.