Improvements in and connected with India Rubber or like Stamps.
Year: 1891

page_text: Date of Application, 17th Oct., 1891
Complete Specification Left, 16th Aug., 1892-Accepted. 17th Sept., 1892
PROVISIONAL SPECIFICATION.
Improvements in and connected with India Rubber or like
Stamps.
We, JOHN WILLIAM BEAUFORT, of 25 Colmore Row, in the City of
Birmingham, Photographer, and FRANK GILMAN, of the Smethwick Boiler
Covering Company, High Park Road, Smethwick, in the County of Warwick,
Manufacturer, do hereby declare the nature of this invention to be as follows:-
Our invention relates to an improvement in stamps of india-rubber or like
substance, and its purpose is to prepare a stamp from a photograph of any object
which shall by inking and stamping accurately reproduce the photograph by
printing on paper or other surface.
We then
In carrying our invention into effect, we prepare on glass or other suitable
surface a gelatine film containing bichromate of potash, and we print on this film
from a negative. The light so acts on the gelatine and bichromate that where
exposed to its influence, the gelatine becomes insoluble in water.
dissolve, off, preferably in a hot water bath, the parts of the gelatine which have
not been acted on by the light, which so remains soluble. This produces a
raised image of the object depicted on the negative, in which tone is caused by the
The lights
partial solubility of the portions more feebly acted on by the light.
and shades of the original photograph are thus accurately followed by the relief
image on the gelatine film, some portions of which, the lightest parts of the
negative or the darkest parts of the original, stand up in relief more than others.
We varnish the plate to which the gelatine film is to be applied with collodion,
before transferring the gelatine film; this protects the raised part and keeps it
together. The gelatine film after printing is stripped with its collodion backing
and we damp the gelatine film to cause it to swell. We oil over the film to prevent
plaster of Paris from sticking, and we pour ou, carefully mixed fine plaster of Paris
or other suitable substance in a fluid or semi-fluid state, and this produces a mould
with the raised parts of the gelatine film hollow.
After the plaster of Paris has sufficiently set and dried we remove the plate, and
into the mould so produced, we press unvulcanized india-rubber to which preferably
sulphur has been added. We remove the block after solidifying and vulcanize by
the ordinary process by exposure to a sufficient temperature.
It will be readily understood that we may copy in this manner any image, repre-
sentation or drawing on a glass or other surface of transparent or partly transparent
nature and it is to be remembered that the stamp may be of gutta percha or other
like substance instead of rubber.
The stamp may be inked from a smooth plate and roller, in any well known
manner, but we prefer to employ our improved system of inking by covering a
smooth surface froin a roller, and transferring the ink so deposited to the surface of
the stamp, by pressing the said stamp upon the inked surface.
Dated this 16th day of October 1891.
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for the Applicants.

page_text: COMPLETE SPECIFICATION.
Improvements in and connected with India Rubber or like
Stamps.
We, JOHN WILLIAM BEAUFORT, of 25 Colmore Row, in the City of
Birmingham, Photographer, and FRANK GILMAN, of the Smethwick Boiler
Covering Company, High Park Road, Smethwick, in the County of Warwick,
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 :-
Our invention relates to an improvement in stamps of india rubber or like
substance and its purpose is to prepare a stamp from a photograph of any object
which shall by inking and stamping accurately reproduce the photograph by printing
on paper or other suitable surface.
In carrying our invention into effect we prepare on glass or other suitable surface
a gelatine film containing bichromate of potash and we print on this film from a
negative. The light so acts on the gelatine and bichromate that where exposed to
its influence the gelatine becomes insoluble in water. We then dissolve off pre-
ferably in a hot water bath, the parts of the gelatine which have not been acted on
by the light, which so remain soluble.
We thus produce a raised image of the object depicted on the negative, in which
tone is caused by the partial solubility of the portions more feebly acted on by the
light. The lights and shades of the original photograph are thus accurately
followed by the relief image on the gelatine film, some portions of which, the
lightest parts of the negative or the darkest parts of the original stand up in relief
more than others.
We varnish the plate to which the gelatine film is to be applied with collodion,
before transferring the gelatine film, this protects the raised part and keeps it
together. The gelatine film after printing is stripped with its collodion backing
and we damp the gelatine film to cause it to swell. We oil over the film to prevent
plaster of Paris or other substance in a fluid or semi-fluid state, and this produces a
mould with the raised parts of the gelatine film hollow.
After the plaster of Paris has sufficiently set and dried we remove the plate, and
into the mould so produced we press unvulcanized india rubber to which sulphur
may or may not have been added. We remove the block after solidifying and
vulcanize by the ordinary process by exposure to a sufficient temperature.
It will be readily understood that we may copy in this manner any image,
representation or drawing on a glass or other surface of transparent or partly
transparent nature and it is to be remembered that the stamp may be of gutta
percha or other like substance instead of rubber.
The stamp may be inked from a smooth plate and roller, in any well known
manner, but we prefer to employ our improved system of inking by covering a
smooth surface from a roller, and transferring the ink so deposited to the surface of
the stamp by pressing the said stamp upon the inked surface.
Referring to the accompanying sheet of drawings which illustrate the application
of our invention :-
Figure 1 is a section through a gelatine positive film prepared in the manner we
have indicated in which raised parts are shown at a, b, c. The section is taken on
the line x, y of the plan Figure 2.
Figure 2 is a plan showing a photograph and the points a, b, c correspond to the
points similarly marked in Figure 1.
Figure 3 shows the same section of the film as in Figure 1 but here a trough is
formed so as to pour on plaster of Paris to obtain a hollow cast.
Figure 4 is a section of the plaster cast obtained as illustrated at Figure 3, but
here the plaster cast is placed in a screw press with a piece of sheet rubber being
pressed into it while the press is heated.

page_text: In carrying our invention into effect we prefer to photograph our negative from
which to print the gelatine plate or film through a ruled screen or a plate having
screen lines photographed upon it, in such manner as to produce fine lines upon the
said negative. When we thus obtain our line ruled negative we print upon the
gelatine bichromate film from the said negative giving a long exposure in order to
sufficiently affect the gelatine film. We then wash away the soluble gelatine
leaving the image and immerse the plate carrying the film in a bath of methylated
spirit leaving it for some hours. We then take out the plate and allow it to dry.
To prepare our plaster cast we place our plate d' carrying the gelatine film at
the bottom of a trough e Figure 3 and pour in first a little very liquid plaster.
This liquid we roll or allow it to flow evenly over the surface of the film in such
manner as to expel as air bubbles and lie close to the film.
We find it unnecessary
to oil the film before pouring on the plaster as we get a sharper mould without the
oil. The plaster may be smoothed in with the finger if necessary. We then fill up
the trough e with plaster to form a substantial thickness and allow it to dry. When
the plaster is thoroughly dry and set we remove the plate d' with its film a by some
sharp tool inserted at the point of junction between the plate and the trough e and
the plaster cast is left with a sharp and clear mould of the gelatine image.
We then invert the mould e with its plaster filling and place on its surface a
piece of sheet unvulcanised rubber y which we then place in a press as shown at
Figure 4 and expose the whole to pressure.
The lower plate of the press and the plaster and rubber is heated by gas
jets i, i, i to a constant temperature of about 200° F., the rubber is thus forced into
the plaster mould and takes the image sharply while hot. The rubber is left under
pressure and subjected to heat for several minutes so as to take the mould sharply
and retain it.
The upper plate k of the press is then unscrewed and the rubber sheet is
pulled off, allowed to cool and cemented to any suitable backing to form a
stamp. The rubber must not contain a sufficient proportion of sulphur to harden
when heated as hereinbefore described otherwise it will be difficult to obtain a
clear print when impressing the stamp upon paper. The stamp is preferably inked
by a roller, which roller is rubbed on a smooth surface to secure a uniform
distribution of the said ink.
Instead of a plaster mould, we sometimes obtain a lead mould by placing a lead
plate over a film prepared as hereinbefore described and exposing to great pressure
in a hydraulic press.
The rubber stamp is prepared from the lead moulds as hereinbefore described
with reference to the plaster mould.
Having now particularly described and ascertained the nature of our said inven-
tion, and in what manner the same is to be performed, we declare that what we
claim is :-
1. The improved process of manufacturing and reproducing printing stamps from
photographic negatives substantially as and for the purposes hereinbefore described
reference being had to the accompanying drawings.
2. Hand stamps composed of rubber or other suitable material substantially as
hereinbefore described and illustrated in the drawings.
3. The process of preparing a rubber hand stamp by means of a gelatine image
from which a plaster or lead cast is taken, the said rubber being forced into the
cast by a press while hot substantially as and for the purposes hereinbefore
described.
Dated this 15th day of August 1892.
MARKS & CLERK,
13, Temple Street, Birmingham, Agents for the Applicants.