An Improved Sensitized Flexible Film for Photographic Purposes.
Year: 1890

page_text: WILLIAM
PROVISIONAL SPECIFICATION.
An Improved Sensitized Flexible Film for Photographic Purposes.
EDWARD
FOXLEE 22 Goldsmith Road Acton London W.
Photographic Expert do hereby declare the nature of this invention to be as
follows:
+
This invention relates to the manufacture of flexible films to be used as a
substitute for glass in taking photographic negatives or positives. It is well known
that thin sheets of celluloid, coated with a sensitive emulsion of gelatino-bromide of
silver have for some time been in use. So also have thinner films of the same
material for what are known as "roller slides." In the manufacture of the former
sheets of commercial celluloid are simply coated with the gelatine emulsion. In the
manufacture of the latter the celluloid compound is spread upon a rigid substance
and afterwards coated with emulsion and when this is dry the film is stripped off.
By either method only sheets of limited size can be produced. As celluloid is a
highly electrical substance it has been found that friction upon its surface--(as when
coating it with the emulsion, stripping it from the rigid body, or by the rollers of
the slides when in use)-evolves electricity the light from which is found to cause
markings or fogging in the negative. When the celluloid film is very thin and
flexible it has a tendency to curl owing to the expansion and contraction of the
gelatine.
By my invention the film is made in continuous lengths and the celluloid is pro-
tected at the back with a coating of gelatine. This serves a double purpose-that
of protecting the celluloid from friction, and by its expansion and contraction in the
different operations of developing, fixing washing, and drying the negative
counteracts the tendency of the film to curl from the expansion and contraction of
the gelatinous film on the other side.
To make my improved film I take a heavily calendered paper in roll-or a surfaced
paper, I then coat it in any convenient manner with a material which is impervious to
water, and which will not disturb the texture or fibre of the paper, such as a
solution of india rubber for example. After the solvent has evaporated I apply a
solution of gelatine containing chrome or other alum sufficient to render the gelatine
insoluble when it is dry, also some soluble non-actinic colouring matter.
coating I apply in the same manner as in making continuous rolls of carbon tissue
for photography. When the gelatinous coating is dry I apply the celluloid
compound (preferably in volatile solvents) either in a fluid or plastic condition
according to the film required.
This
After the solvents have evaporated the celluloid is coated, in a darkened room,
with the sensitive gelatino-bromide of silver. When this is dry the back of the
paper is moistened with a solvent of the first coating, then the finished film is
separated from the paper. Or the compound film of gelatine and celluloid may be
removed from the paper first and coated with the emulsion afterwards.

page_text: COMPLETE SPECIFICATION.
An Improved Sensitized Flexible Film for Photographic Purposes.
1, EDWARD WILLIAM FOXLEE, of 22, Goldsmith Road, Acton, London, W.,
Photographic Expert, 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 manufacture of improved flexible films to be used as
a substitute for the ordinary sensitized glass in taking photographic negatives or
positives.
It is well known that thin sheets of celluloid coated with a sensitive emulsion of
gelatino-bromide of silver, have for some time been in use, so also have thinner
films of the same material, for what are known as roller slides. In the manufacture
of the former, sheets of commercial celluloid are simply coated with the emulsion.
In the manufacture of the latter, the celluloid compound is spread upon a rigid
surface and afterwards coated with the emulsion, and when this is dry the filin is
stripped off. By either method only sheets of limited size can be produced. As
celluloid is a highly electrical substance, it has been found that friction upon its
surface, as when stripping it from the rigid body, or by the rollers of the slide when
in use, evolves electricity, the light from which is found to cause marking or fogging
in the negatives.
When the celluloid film is very thin and flexible, it has a tendency to curl owing
to the expansion and contraction of the gelatine on being wetted or dried.
By my invention the film is made in continuous or long lengths or webs, and the
celluloid is protected at the back with a coating of gelatine, which serves a double
purpose, that of protecting the celluloid from friction, and by its expanding and
contracting in the different operations of developing, fixing, washing and drying
the negative, counteracts the tendency of the film to curl from the expansion and
contraction of the gelatinous film on the other side.
To make my improved film, 1 take a heavily calendered paper in the roll or web, or
a "surfaced" paper; I then coat it in any convenient manuer with a material which
is impervious to water and which will not disturb the fibre or texture of the paper,
such as a solution of india rubber for example. After the solvent has evaporated,
I apply a solution of gelatine containing chrome or other alum sufficient to render
the gelatine insoluble or partially insoluble when it is dry, combined or not with
some soluble non-actinic coloring matter. The proportion of gelatine to water may
be about the same as that in the sensitive emulsion. This coating I apply in the
same manner as in making continuous or long lengths or webs of carbon tissue for
photography or in coating gelatino-bromide paper. The india-rubber solution can
also be applied to the paper in the same way as the gelatine.
When the gelatinous coating is dry I apply the celluloid or pyroxiline compound
(preferably prepared with volatile solvents) either in a fluid or in a plastic condition,
according to the film required. When the celluloid or pyroxiline compound is
employed in the fluid state, it can be applied to the web in the same manner as the
previous coatings above referred to. When such compound is used in the plastic
state it can be spread on the web in the same way as india-rubber and similar
substances are spread. The celluloid or pyroxiline compound I employ is similar to
what is known as xylonite, celluloid, &c., and is composed of nitro-cellulose and
camphor dissolved in suitable solvents (the camphor being itself a solvent) of
which there are many; those I prefer to employ for the compound when the latter
is used in the fluid condition, on account of their volatility, are such as methyl-
alcohol (wood naphtha) methylated alcohol, ether, benzol, &c., or mixtures of two
or more of the same. If the said compound is to be used in the plastic state,
some of the other well known and less volatile solvents are preferable; I would
have it understood however that I do not confine myself to the use of any particular
solvents or proportions, as they have to be varied to suit circumstances; a good

page_text: proportion however for a fluid compound is from four to six parts of solvent to one
of solid matter.
After the solvents have evaporated, the celluloid is coated in a darkened room,
with the sensitive gelatino-bromide of silver emulsion; when this is dry the back of
the paper is moistened with a solvent of the first coating, such as benzol in the case
of india-rubber; the finished film is then separated from the paper support or
backing; this may advantageously be effected by connecting the ends of the film
and paper to two separate rollers, which on simultaneous rotary motion being given
to them, will act to separate the film from the paper and wind them up respectively
thereon.
I would here remark that I am aware that a collodion film has been spread on
paper whilst the latter has been attached to a sheet of glass and such film has then
been coated with sensitized emulsion, but in such case the paper has remained
attached to the film and was not separated therefrom until after the negative had
been exposed, developed and fixed.
I am also aware that paper has been coated with soluble gelatine which has then
received the sensitive emulsion rendered insoluble with chrome alum, and that the
back of the paper has been coated with insoluble gelatine to prevent the film
curling. In this film the paper has formed part of it until after exposure,
developement, and fixing, when the film bearing the image is stripped off the paper,
which latter carries with it the insoluble gelatine backing. In this case collodion
or celluloid is not used.
I am also aware that a photographic film has been prepared by first coating paper
with insoluble gelatine, then with india-rubber containing grease or wax, then with
collodion, on which is put a layer of gelatine, and on the latter the sensitive
emulsion. Sometimes the plain gelatine is omitted. When using the above film the
paper is not removed until the picture is finished.
It has also been proposed to produce photographic films by using a temporary
support, such as waxed paper, which is first coated with soluble gelatine, then with.
algin, which is afterwards rendered insoluble, then with the sensitive emulsion, cach
coating being dried before the next is applied; in this case the paper backing may
be detached from the film at any time by treatment with warm water, but no
mention is made of the use of collodion or celluloid in the preparation of this film.
Photographic films have also been prepared by spreading a collodion compound
upon glass plates, on which, when dry, the sensitive emulsion is applied.
I therefore lay no claim to the various methods of forming photographic films
above referred to, nor do I claim any of the steps of the process herein described
separately considered.
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 :-
A transparent flexible film for photographic purposes composed of a nitro-
cellulose compound with a coating of insensitive gelatine on the one side and a
coating of sensitive gelatine emulsion on the other, made in continuous or long
lengths or webs upon a temporary paper support, which is removed from the film
before use of the latter, substantially as herein described.
Dated this 2nd day of December 1890.
EDWD. WM. FOXLEE.
By Harris & Mills,
23, Southampton Buildings, London, W.C., Agents: