The Manufacture of a Transparent Flexible Material Suitable for all Purposes where a Transparent, Flexible, and Light Material is Required, such as a Base for Photographic Pictures, Trans- parent Show Cards, Artistic Work, similar and other Purposes.
Year: 1886

page_text: Date of Application, 20th Aug., 1886.
Complete Left, 5th May, 1887.
Complete Accepted, 7th June, 1887.
DEE
The Manufacture of a Transparent Flexible Material Suitable for
all Purposes where a Transparent, Flexible, and Light Material
is Required, such as a Base for Photographic Pictures, Trans-
parent Show Cards, Artistic Work, similar and other Purposes.
I FRANCIS HENRY FROEDMAN Pharmaceutical Chemist of Ireland 23 Mary Street,
Dublin, Ireland do hereby declare the nature of this invention to be as follows:-
It consists in rendering Gelatine, Glue or other colloidal bodies insoluble with
Chromium salts, preferably the Bichromate of potash, and converting them into
colourless, transparent & pliable films by means of Sulphurous Acid or its compounds;
suitable as a flexible support, substituting Glass in various well known photographic
processes as well as other purposes.
The improved method of rendering said Gelatine, Glue or colloidal bodies so as to
allow it to be coated with any hitherto existing sensitive Emulsion either hot or cold
and the film bearing the image not being necessary to be isolated.
In order to carry out my invention for photographic purposes I use the best
Gelatine either of a hard or soft kind, according to circumstances, which I soak for a
certain time in Water to soften it, then heat on a Water-bath with a certain quantity
of Water until dissolved, add a suitable proportion of a Solution of a Chromium salt,
preferably Bichromate of potash, mix thoroughly then add Alcohol in certain propor-
tions to make it flow easily when covering Glass plates or other suitable material,
lastly add a small quantity of Glycerine if necessary to give it pliability and softness.
The Glass plates are previously prepared in the following manner: Glasses free
from scratches and perfectly flat are first thoroughly cleaned and polished by the
usual methods, then rubbed over with finely powdered French chalk, the excess of
which is brushed lightly off. Coat the Glass plate with suitable Collodion (so
called Enamel collodion) containing if necessary some castor-oil; when set, immerse
in Water until the coated surface is free from grensiness, which is indicated by the
Waier running freely and without streaks over its surface, let it drain and pour the
hot Gelatine solution containing the Chrome salt over it, spread it or use mechanical

page_text: means to cover it, when evenly coated put on levelling slab to set, let dry free from
dust in suitable chambers at a temperature of about 65 to 70° Fahrenheit.
When dry expose it to light, either sunlight or shade, to convert the films into an
insoluble compound, which is indicated by the colour changing from yellow to brown.
A certain amount of practice is necessary to have it rendered suitable for the
purpose.
Now wash the plate bearing the insoluble compound in Water to remove any
unaltered Chrome salt and immerse said plate in a Solution of Sulphurous acid or its
compounds; when sufficiently bleached wash the plate in several changes of Water
until no more acidity is perceptible. Alum solution may also be used if a tougher
film is desirable. Put the film to dry and finally cover with any of the existing
photographic Emulsions either by hand or by machinery-then dry in suitable
chambers or boxes. When quite dry the edgos of the film on the Glass is cut and
will strip off quite flat and easy and are then fit to be used in any of the existing dark
slides by means of suitable supports, or they can be made in long sheets so as to be
suitable in roller slide.
The following is a formula which may be used advantaceously ‹
•
compounds; when sufficiently bleached wash the plate in several changes of Water
until no more acidity is perceptible. Alum solution may also be used if a tougher
film is desirable. Put the film to dry and finally cover with any of the existing
photographic Emulsions either by hand or by machinery-then dry in suitable
chambers or boxes. When quite dry the edges of the film on the Glass is cut and
will strip off quite flat and easy and are then fit to be used in any of the existing dark
slides by means of suitable supports, or they can be made in long sheets so as to be
suitable in roller slide.
The following is a formula which may be used advantageously.
Take of Best hard Gelatine
Water
-
Solution Bichromate of potash (6%)
Alcohol
Glycerine (if necessary)
Dissolve, filter and proceed as described above.
3 parts
24 parts
8 parts
->
4 parts
part
The flexible films when used for photographic negatives are exceedingly easy to
manipulate and the results obtainable upon them are equal to the finest Glass negatives.
They are of very little weight, are not affected by damp, do not shrink once they are
dry nor expand when wet.
Having now particularly described the nature of my invention and in what manner
the same is to be performed, I declare that what I claim is :
1.) The process of rendering Gelatine, Glue or other colloidal bodies insoluble and
perfectly transparent almost colourless as a flexible support in place of Glass by
means of Chromium salts and Sulphurous acid or its compounds.
2.) In combination with rondoring said bodies insoluble, transparent and colourless
by the process described, the method of proparing them to receive a coating of
Emulsion for the purpose of obtaining photographic negatives.
3.) Being unaffected by hot or cold Water, its insolubility in dilute Acids and
Alcalies, its perfect transparency, unbreakable yet can be bent. Its cheapness over
Glass.
Dated this 19th day of Anust 1886

page_text: The Manufacture of a Transparent Flexible Material Suitable for
all Purposes where a Transparent, Flexible, and Light Material
is Required, such as a Base for Photographic Pictures, Trans-
parent Show Cards, Artistic Work, similar and other Purposes.
FRANCIS HENRY FROEDMAN Pharmaceutical Chemist of Ireland 23 Mary Street
Dublin Ireland, 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 :—
It consists in rendering Gelatine, Glue or other colloidal bodies insoluble with
Chromium salts, preferably the Bichromate of Potash, and converting these bodies
into colourless, transparent and pliable films by means of Sulphurous acid or its
compounds; suitable as a flexible support as a substitute of Glass in various well
known photographic processes as well as other purposes.
In order to carry out my invention for photographic purposes I use the best
Gelatine either of a hard or soft kind, according to circumstances, which I soak for a
certain time in Water to soften it, then heat on a Water-bath with a certain quantity
of water until dissolved, add a suitable proportion of a solution of a Chromium salt,
preferably Bichromate of potash, mix thoroughly then add Alcohol in certain pro-
portions to make it flow easily when covering Glass plates or other suitable material,
Jastly add a small quantity of Glycerine if necessary to give it pliability and softness.
The Glass plates are previously prepared in the following manner: Glasses free
from scratches and perfectly flat are first thoroughly cleaned and polished by the
usual methods, then rubbed over with finely powdered french chalk, the excess of
which is brushed lightly off. Coat the Glass plate with suitable Collodion (so called
Enamel Collodion) containing if necessary some castor oil; when set immerse in
Water until the coated surface is free from greasiness, which is indicated by the
Water running freely and without streaks over its surface, let it drain and pour the
hot Gelatine solution containing the Chrome salt over it, spread it or use mechanical
means to cover it, when evenly coated put the Glass on levelling slab to set, let it dry
free from dust in suitable chambers at a temperature of about 65 to 70° Fahrenheit.
In place of covering the Glass plates with a substratum of Collodion,―the Collodion
may be left out, and the Glass plates to receive only a safe edging with a solution of
India-Rubber in Benzole ;-or the Glass may be ground on the edges to keep the
films in their place during after treatment.
When dry expose it to light, either sunlight or shade, to convert the films into an
insoluble compound, which is indicated by the colour changing from yellow to brown.
A certain amount of practice as regards the time of exposure is necessary to have it
rendered suitable for the purpose.
Now wash the plate bearing the insoluble compound in Water to remove any
unaltered Chrome salt, previously receiving another safe edging of a solution of

page_text: India-Rubber in Benzole and lastly immerse said plate in a solution of Sulphurous
acid or its compounds; when sufficiently acted upon by the acid, wash the plate in
several changes of water until no more acidity perceptible.
Put tho films on their support to dry and finally cover with any of the existing
photographic Emulsions either by hand or by mechanical means, then dry in suitable
dark chambers or boxes. When quite dry, the edges of the film on the Glass are cut
and will strip off quite fint and easy and are then fit to be used in any of the existing
dark slides by means of suitable supports, or they can be made in long sheets so as to
be suitable in roller dark slides.
The following is a formula which may be used advantageously :
AXICONOT
Glycerine
Dissolve, filter through flannel and proceed as described above.
t part
The flexible films when used for photographic negatives are exceedingly easy to
manipulate and the results obtainable upon them are equal to the finest Glass
negatives. They are of very little weight, are not affected by damp, do not shrink
once they are dry, nor expand when wet.
Having now particularly described and ascertained the nature of my said Invention,
and in what manner the same is to be performed, I declare that what I claim is :
1.) The process of rendering Gelatine, Glue or other colloidal bodies insoluble and
perfectly transparent almost colourless as a flexible support in place of Glass by means
of Chromium salts and sulphurous acid or its compounds.
2.) In combination with rendering said bodies insoluble, transparent and colourless
by the process described; the method of preparing them to receive a coating of
Emulsion for the purpose of obtaining photographic negatives.
3.) Being unaffected by hot or cold Water, their insolubility in dilute acids and
alcalies, their perfect transparency, unbreakable yet can be bent.
1005
FRANCIS HENRY FROEDMAN,
Pharmaceutical Chemist of Ireland.