Improvements in or relating to the Manufacture of Sensitized Films for Carbon Printing.
Year: 1892

page_text: Date of Application, 15th June, 1892
Complete Specification Left, 15th Mar., 1893-Accepted, 22nd Apr., 1893
IDIOT
Improvements in or relating to the Manufacture of Sensitized Films
for Carbon Printing.
1, JOSEPH THACHER CLARKE, of 3 College Road, Harrow, in the County of
Middlesex, Architect, do hereby declare the nature of this invention to be as
follows:
In carrying out this invention I may conveniently proceed by using the apparatus
set forth in the Eastman Patent No. 198968, and carrying out the process set
forth in the Eastman Patent No. 198978, and I produce gelatino-carbon films of
the usual kind made of gelatine and colouring matter with the optional addition of
soap, dextrine or the like. When the film is to be sensitized in the manufacture
bi-chromate of potash is added.
In manufacturing such carbon films it has been customary to place the film upon
a backing of paper and after the exposure which renders portions of the film
insoluble to dissolve out the remaining portions. As however this method produced
the insoluble surface upon the outer side of the film it was necessary to transfer
the entire film to another backing, after which, on removing the original paper
supports the prints could be obtained by treatment with warm water in the well-
known manner.
In carrying out my invention instead of employing the paper support I form
such support of a film of celluloid or transparent insoluble gelatine sufficiently thin
to allow of the image being received by the sensitive material through said film.
The soluble portions of the gelatino-carbon film may then be removed by washing
in the usual manner, and the film is ready for use without the necessity of trans-
ferring it to any other support or removing the original support.
A further advantage of the method is that the image is not reversed as regards
right and left, as is the case in the transfer process.
Having obtained the carbon image upon the celluloid or insoluble gelatine
support, the picture may be mounted upon cardboard of suitable colour, or upon
glass, if it be intended to be seen as a transparency.
Dated this 15th day of June 1892.
W. P. THOMPSON & BOULT,
Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in or relating to the Manufacture of Sensitized Films
for Carbon Printing.
I, JOSEPH THACHER CLARKE of 3 College Road, Harrow, in the County of
Middlesex, Architect, 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 carrying out this invention I may conveniently proceed by using the apparatus
set forth in the Eastman Patent No. 19896 of 1889, and carrying out the process
set forth in the Eastman Patent No. 19897 of 1889, and I produce gelatino-carbon
films of the usual kind made of gelatine and colouring matter with the optional
addition of soap, dextrine, or the other materials commonly used in the trade.
When the film is to be sensitized in the manufacture bi-chromate of potash is
added.
In manufacturing such carbon films it has been customary to place the film upon

page_text: a backing of paper and after the exposure which renders portions of the film
insoluble to dissolve out the remaining portions. As however this method pro-
duced the insoluble surface or image upon the outer side of the film it was necessary
to transfer the entire film to another backing, after which, on removing the original
paper supports, the prints could be obtained by treatment with warm water in the
well-known manner.
In carrying out my invention instead of employing the paper support I form such
support of a film of celluloid or transparent insoluble gelatine sufficiently thin to
allow of the image being received by the sensitive material through said film. The
film is ready for use without the necessity of transferring it to any other support or
removing the original support and the soluble portions of the gelatino-carbon film
may after printing be removed by washing in the usual manner.
A further advantage of the method is that the image is not reversed as regards
right and left, as is the case in the transfer process.
Having obtained the carbon image upon the celluloid or insoluble gelatine
support, the picture may be mounted upon cardboard of suitable colour, or upon
glass, if it be intended to be seen as a transparency.
"
I do not bind myself to use only "carbon as the pigment or colouring matter
of the film, neither do I restrict myself to the subjects of the before mentioned
Patents Nos. 1989689 and 1989789 as the invention is applicable to films prepared
by other processes.
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 combination with " carbon
a
"
66
or pigment" film or tissue of a trans-
parent backing whereby the image can be obtained through the back.
2. A celluloid transparent backing to a "pigment" film for photographic
purposes substantially as and for the purpose described.
Dated this 14th day of March 1893.
JOSEPH THACHER CLARKE.
W. P. Thompson & Boult,
Agents for the Applicant.