Improvements in Means for Facilitating the Separation of Gelatine Coatings from Paper Supports in the Manufacture of Photographic Films.
Year: 1895

page_text: Date of Application, 18th June, 1895
Complete Specification Left, 18th Mar., 1896-Accepted, 18th Apr., 1896
PROVISIONAL SPECIFICATION.
Improvements in Means for Facilitating the Separation of
Gelatine Coatings from Paper Supports in the Manufacture
of Photographic Films.
JAMES BOOKER BLAKEMORE WELLINGTON The Elms Elstree Herts,
Manufacturer of Photographic Papers, do hereby declare the nature of this
invention to be as follows:-
This invention relates to a mode of preparing a paper support upon which a
photographic film consisting wholly or in part of gelatine can be coated, from
which support the photographic film can be stripped prior to its being coated
with emulsion.
My invention consists in the treatment of a temporary backing of paper with a
substratum which permits the ready stripping of a gelatine coating made upon it
from this support. The said treatment is based upon the employment of gums in
alcoholic solution as this preparatory substratum.
In carrying my invention into effect I coat upon any suitable paper, as for
instance upon the well known photographic paper coated with baryta whether matt
or callendered a substratum containing a suitable proportion of any gum or resin
dissolved in any of the well known solvents which are in general use for this
purpose. In practice I have found that equal parts of gum mastic and gum
thus dissolved in methylated spirit will give satisfactory results; but I am aware
that good results may be obtained with mastic & thus in varying proportions or
with other gums and resins as for instance damar, copal and their congeners. The
thickness of the solution of these gums is in like manner capable of considerable
variation, and will depend in great measure upon the means which are adopted for
coating the paper, for instance if the paper be coated by immersion in a trough,
a solution of twenty parts of gum mastic, twenty parts of gum thus and
five hundred parts of methylated alcohol will be found to answer satisfactorily.
Having thus prepared my paper backing by coating it with a substratum of
gum and permitted it to dry I proceed to coat thereupon a layer of gelatine which
may if desired be rendered insoluble by the addition thereto immediately prior to
coating a suitable proportion of soda alum chrome alum or any of those well known
chemicals which have the property of rendering gelatine insoluble when dry.
Upon this gelatine I may coat a celluloid film preferably doing this in the
manner set forth in Letters Patent No. 14274 of 1893. The film body may in
like manner be formed of any transparent material other than celluloid which is
capable of conjunction with the gelatine substratum in the manner set forth.
When the film body however composed has become thoroughly dry, I strip it
together with the gelatine upon which it was coated or of which alone it consists,
from the paper backing: the function of the substratum of gum proposed in my
invention being to facilitate the separation of the gelatine from the paper. The
support for photographic emulsions thus obtained may then be coated with emulsion:
the gelatine surface being particularly well adapted to receive, and to cause the
adhesion of, the sensitized vehicle.
Dated this Eighteenth day of June 1895.

page_text: Improvements in Means for Facilitating the Separation of
Gelatine Coatings from Paper Supports in the Manufacture
of Photographic Films.
I, JAMES BOOKER BLAKEMORE WELLINGTON, of The Elms, Elstree, in the
County of Hertford, Manufacturer of Photographic Papers, 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 a mode of preparing a paper support upon which a
photographic film consisting wholly or in part of gelatine can be coated, from
which support the photographic film can be stripped prior to its being coated with
emulsion.
My invention consists in the treatment of a temporary backing of paper with a
substratum which permits the ready stripping of a gelatine coating made upou it
from this support. The said treatment is based upon the employment of gums in
alcoholic solution as this preparatory substratum.
In carrying my invention into effect I coat upon any suitable paper, as for
instance, upon the well known photographic paper coated with baryta whether
matt or calendered, a substratum containing a suitable proportion of any gum or
resin dissolved in any of the well known solvents which are in general use for this
purpose. In practice I have found that good results may be obtained with gum
mastic and gum thus, in varying proportions dissolved in methylated spirit, or with
other gums and resins as for instance damar, copal and their congeners, but I
preferably use gum saudarac or gum copal. The consistency of the solution of
these gums is in like manner capable of considerable variation, and will depend in
great measure upon the means which are adopted for coating the paper, for
instance, if the paper be coated by immersion in a trough, a solution of one part
of gum sandarac or gum copal and ten parts of methylated alcohol will be found
to answer satisfactorily.
Having thus prepared my paper backing by coating it with a substratum of
gum and permitted it to dry I proceed to coat thereupon a layer of gelatine
which may if desired be rendered insoluble by the addition thereto, immediately
prior to coating, of a suitable proportion of soda alum, chrome alum or any of
these well known chemicals which have the property of rendering gelatine insoluble
when dry.
Upon this gelatine I may coat a celluloid film preferably doing this in the
manner set forth in the Specification of Letters Patent No. 14274 of 1893.
The film body may in like manner be formed of any transparent non-hygroscopic
material other than celluloid which is capable of conjunction with, that is to say
adhering to the gelatine substratum in the manner set forth.
If desired in lieu of coating the gummed paper with gelatine and the latter
with celluloid and then after stripping the film from the gummed paper applying
sensitive emulsion to the gelatine surface of said film I may apply a sensitive
emulsion direct to the gummed paper and afterwards apply a backing of celluloid
or other suitable transparent material thereto.
When the film body however composed has become thoroughly dry, I strip it
together with the gelatine upon which it was coated or of which alone it consists
from the paper backing preferably by winding the film upon one roller and the
gummed paper backing upon another roller the function of the substratum of gum
proposed in my invention being to facilitate the separation of the gelatine from
the paper.
In case the gelatine film has been coated with celluloid or other
transparent non-hygroscopic material the film obtained may then be coated with

page_text: sensitive emulsion: the gelatine surface being particularly well adapted to receive,.
and to cause the adhesion of the sensitized vehicle.
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 improved means for facilitating the separation of gelatine coatings from
paper supports in the manufacture of photographic films substantially as herein
described.
2. In means for facilitating the separation of gelatine coatings from paper
supports in the manufacture of photographic films, the interposition of a coating
or substratum of gum between the paper and the gelatine coating substantially as
herein described.
Doted March 18th 1906
By HARRIS & MILLS,
23 Southampton Buildings, London, W.C., Agents.
By HARRIS & MILLS,
23 Southampton Buildings, London, W.C., Agents.