Improvements in the Manufacture of Photographic Films.
Year: 1890

page_text: Date of Application, 3rd Sept., 1890
Complete Specification Left, 3rd June, 1891-Accepted, 4th July, 1891
PROVISIONAL SPECIFICATION.
Improvements in the Manufacture of Photographic Films.
I, JOSEPH JOHN ACWORTH, of Brondesbury, London, N.W. Doctor of
Philosophy do hereby declare the nature of this invention to be as follows:-
My invention consists firstly, in preparing a film of gelatine or other analogous
substance, either toughened or not, by coating a suitable support with a strong
solution of gelatine, containing glycerine or other similar material in order to
render it pliable. Such support may consist of a band of American leather cloth
of suitable quality and dimensions, or of any other suitable material. When the
gelatine coating has set and dried it is stripped off the support in the form of a
film and rolled on to a roller; after which it is passed through a solution of
pyroxyline or nitro-cellulose, so as to coat both sides of the film with a thin coating
of the solution. This solution consists of pyroxyline dissolved in any suitable
solvents such as solutions of amyl alcohol, and amylic acetate made of any suitable
strength; say, containing about 5% of pyroxyline. The film is then dried cither
by passing dry air over the coated surfaces; or by placing it in a room kept at a
suitable temperature; or by passing it through a suitably constructed hot air
chamber containing circulating hot air at, say, about 200° Fahrenheit. This latter
method will be found very convenient particularly when long lengths of film have
to be coated as they can be rolled as they are withdrawn from the hot air chamber,
thus economising space.
ELT & Co.,
33, Southampton Buildings, Holborn, London, Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in the Manufacture of Photographic Films.
JOSEPH JOHN ACWORTH of Brondesbury London N.W. Doctor of
Philosophy 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 :-
The object of this invention is to facilitate the economic manufacture of
gelatinous photographic films so as to render them sufficiently impervious to the
action of water for photographic purposes.
My invention consists firstly in preparing a film of gelatine or other analogous
substance such as isinglass either toughened or not by coating a suitable support
with a strong solution of gelatine preferably containing glycerine or other similar
material in order to render it pliable. Such support may consist of a band of
American leather cloth of suitable quality and dimensions, or of any other suitable
material. When the gelatine coating has set and dried it is stripped off the support
in the form of a film and rolled on to a roller, after which it is passed through a
solution of pyroxyline or nitro-cellulose, so as to coat both sides of the film with a
thin coating of the solution thus rendering the film waterproof or nearly so and
facilitating the subsequent manipulation of such film. The solution employed
consists of pyroxyline dissolved in any suitable solvents such as mixture of amyl
alcohol and amylic acetate made of any suitable strength; say containing from
about 3 to about 5 or 6 per cent. of pyroxyline. The film is then dried either by
passing dry air over the coated surfaces; or by placing it in a room kept at a
suitable temperature; or by passing it through a suitably constructed hot air

page_text: chamber containing circulating hot air at say about 200° Fahrenheit. This latter
method will be found very convenient particularly when long lengths of film have
to be coated, as they can be rolled as they are withdrawn from the hot air chamber,
thus economising space.
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
Coating gelatinous photographic films on both sides with a solution of pyroxyline
or nitro-cellulose so as to render them waterproof or nearly so all substantially as
herein before described.
Dated this 3rd day of June 1891.
ELT & Co.,
33, Southampton Buildings, Holborn, London, Agents for Applicant.