Improvements in Photographio Films.
Year: 1899

page_text: Date of Application, 8th July, 1899
Complete Specification Left, 31st Jan., 1900-Accepted, 14th Apr., 1900
Improvements in Photographio Films.
I, JOHN EDWARD THORNTON, of Rokeby, Oldfield Road, Altrincham, Cheshire,
do hereby declare the nature of this invention to be as follows:-
The object of this invention is to produce a photographic film (such as is
used for making negatives or positives upon) which shall remain flat, or flatter
than the so called flat or cut sheet films at present known and used, without
making them any thicker than usual to obtain this important feature.
Hitherto such films have generally been made out of sheet celluloid cut up
to the proper size for use. Although other substances (such for instance as
hardened gelatine) have been tried, they have not proved satisfactory, and cellu-
loid, in some form or other, is therefore commonly used. This material pos
sesses the disadvantage that, although it may be flat when produced, it does
not remain so, and unless the film is made very thick indeed (too thick, in
fact, to be cheap enough for general use) it will probably curl slightly before
exposure, and will curl still more when the sensitized gelatinous coating is
wet, as when in the developing and other solutions for instance.
The method I adopt is to form a rim or stiffening round the edges of the
film, which may be carried out in several ways, as follows. Any suitable
material (such as celluloid for instance) may be used.
(1) The film material is moulded or pressed. (preferably whilst soft or in a
plastic state) in suitable dies, whereby the edges are left thick and the other
part thin. For instance the rim may be say 1/8" wide x 1/16" thick. whilst
the portion surrounded by the rim may be say from 3/1000" to 10/1000". It
is preferable to coat such films with the sensitive emulsion after forming the
rim, and I prefer to apply such emulsion to the side of the film opposite from
the rim side, but the emulsion may of course be applied to the other, or to
both sides, of the film.
(2) Ordinary sheet film cut to size is placed between suitable dies, which
are so arranged as to form a stiffened rim round the edges of the film by forming
an indented line in the film near the edge; or by turning the edge over at
right angles to the face; or by turning the edge completely over; or by a
combination of indented line and turn over.
(3) A rim made of U shaped thin sheet metal or similar stiffening material
is attached to the edges of a sheet film by pressure in a press or other suitable
way, and the completed film is dished slightly, equal to the thickness of the
metal in order to bring its surface into the correct plane. Such rims may be
made out of sheet, the portion cut out from the centre being either thrown
away or used for making smaller sizes of rims; but in the case of very expen-
sive metals (such for instance as thin sheet aluminium) I find this too expensive,
and therefore I form each rim by joining up in two or four pieces. These
may, if desired, be dovetailed into each other at the corners of the rim, but
in many cases this is unnecessary.
(4) An ordinary sheet film, cut to size, is placed in a suitable mould and a
rim is moulded thereon of any suitable liquid or plastic material capable of
setting hard

page_text: In methods 2, 3, and 4 the sensitive coating is preferably (but not neces-
sarily) applied to the sheet film before forming the stiffening rim thereon.
In many cases, however, it may be found that the stiffening rim has served
its purpose after the film has been exposed, developed, washed, and dried, and
in that case the rim may be cut off by a pair of scissors, a knife, or other
convenient tool.
To further facilitate the easy removal of the rim, I may, instead of making
it continuous, form breaks or notches in the rim at the angles formed by
each two sides, such breaks being wide enough to admit the cutting tool
easily. Thus actual cutting of the rim itself is obviated.
There are many advantages in stiffened films made according to this inven-
tion. For instance, if used for negative making they require no carriers or
any other of the usual', means for keeping them flat when being used in dark
slides, magazines, and the like. They are specially advantageous in many forms
of changing apparatus as the manipulation of the films therein is. thereby
rendered as easy as, and sometimes easier than, glass plates. They are, for
all practical purposes as rigid as glass plates, without the weight and fragility.
Then if used for lantern slides they require no cover glass or binding material
round the edges, although such may be added if desired. If used as either
transparent or opaque positives they need no frame or mounting card; the
stiffening rim enables them to be placed in any position and gives a finished
appearance. This latter may be still further enhanced by suitable masks or
borders which may consist of paper or other material attached to the film, or
embedded therein during manufacture, or colored pigment applied at any con-
venient time during manufacture or use."
For magazines, and in other cases where the films are placed behind each
other and the front one exposed, or for the purpose of preventing halation, I
make the back of the film opaque, either by attaching a black paper thereto,
or by the application of a coating of pigment; in either case the opaque backing
comes off as soon as the film is wetted, or it can be stripped off by the operator
when dry.
.
Improvements in Photographic Films.
I, JOHN EDWARD THORNTON, of Rokeby, Oldfield Road, Altrincham, in the
County of Chester, Manufacturer, 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 produce a photographic film (such as is
used for making negatives or positives upon) which shall remain flat, or flatter
than the so called Hat or cut sheet films at present known and used, without
making them any thicker than usual to obtain this important feature.
Hitherto such films have generally been made out of sheet celluloid cut up
to the proper size for use. Although other substances (such for instance as
hardened gelatine) have been tried, they have not proved satisfactory, and cellu-
loid, in some form or other, is therefore commonly used. This material pos-
sesses the disadvantage that, although it may be Hat when produced, it does
not remain 80, and unless the film is made very thick indeed (too thick, in
fact, to be cheap enough for general use) it will probably curl slightly before

page_text: exposure and will curl still more when the sensitized gelatinous coating is
wet and when in the developing and other solutions for instance, and also
during the subsequent drying.
The invention consists essentially in forming or constructing the film with a
rim or rib round the edge to stiffen it either by indenting moulding or thickening
the edge or by applying thereto a rim of the same material or other etiff
material which will prevent the film easily or readily bending.
The invention will be fully described in reference to the accompanying
drawings in which a front and a part sectional elevation of the various methods
are shown the sections in each case being enlarged several times natural size
for the purpose of illustration.
The films may be made of any suitable plastic material capable of being
spread or otherwise formed into a thin sheet and also capable of being moulded
or impressed such as celluloid; insoluble gelatine or other substance prepared
for photographic films and either with or without a base or backing of other
material either permanently attached or capable of being removed or stripped
therefrom:
Referring to Figs. 1 and 2 a rib or bead a is formed around. the edge of
the film A by moulding or pressing the plastic mass of the material in a mould
whilst it is setting. The rim or head a may be say about of an inch wide
and thick the portion of the film surrounded thereby being from 3/1000
to 10/1000 of an inch in thickness. The rib or rimi a is preferably raised or
applied at one side of the film only the other side being perfectly flat to the
edges and in coating with the sensitive emulsion it is desirable to coat the film
after the rib or rim has been formed thereon and to apply the emulsion to the
flat side of the film. The emulsion however may be applied to either or both
sides of the film.
Referring to Figs. 3 and 4 the stiffening rim or rib a is formed around the edge
of the film by indenting the film on one side and raising the indentation in
the form of a rib on the opposite side. The sheet is cut to size and then
placed between suitable dies by which it is pressed into the shape shown, or
the sheets before being cut preferably while still soft or not thoroughly dry
are pressed or moulded with the ribs which then forms the edge of the films
when the sheet is cut up.
Referring to Figs. 5 and 6 the stiffening rim or rib a is formed around the
edge of the film by turning the edge over at an angle to the face. It is pre-
ferred to turn the edge forming the rim a at right angles to the plane of the
film but it may be placed at any other angle greater or less than a right angle.
The sheet is cut to the desired size and then pressed or stamped with suitable
dies.
Referring to Fig. 7 the stiffening rim or rib a is formed by turning the edge
completely over and pressing it against the opposite side. The sheet is cut to
the desired size and the edge turned over by suitable dies.
Referring to Figs. 8, 9 and 10 the edge is stiffened by a double rim or rib a
formed by indenting the sheet on one side and raising it on the other as shown
in Fig. 4 and by turning over the edge as shown in Fig. 6 or as shown in
Fig. 7.
Referring to Figs. 11. 12, 13 and 14, the stiffening rim is formed of thin
sheet metal or other stiff material of U shape attached to the edges of the film
by pressure. The rims may be stamped from sheets the portion cut out from
the centre being discarded or used for rims for smaller sized films but as this
is an expensive way of making the rims-especially when aluminium is used
for the purpose-the rim may be formed of two or more pieces jointed together
as in Fig. 13 in which are shown the pieces dovetailed together at the corners.
The film may be left flat with the metal rims a projecting at both sides or the
film may be dished as in Fig. 14 to place the rim a and the film level on one
side.
3.

page_text: Referring to Figs. 15, 16 & 17 the strengthening rim or riba is formed of
metallic strips of U section attached to the edges of the film by compression
as described with reference to the previous figures. The rim or rib is not
continuous but to facilitate its easy removal by cutting breaks notches or cuts b
are formed to admit of the passage of a scissors or a knife to cut off the rim.
Referring to Figs. 18, 19 & 20 the stiffened rim or riba is formed by
moulding around the edge of the film a rim of soft or plastic material such as
that of which the film is made or pulp or other suitable material which will
set stiff on drying. The film is cut to the desired size and placed in a mould
and the plastic material moulded round the edge. The film may remain flat
as in Fig. 19 or be dished as in Fig. 20.
Referring to Figs. 21, 22 & 23 the stiffened rim or rib a is formed by strips
or pieces of cardboard turned over and compressed around the edges of the
film. A piece of cardboard a' is turned over at three edges forming a kind of
sheath; into this the film A is slipped from the side not turned over thus
forming a rib along thice sides of the film the back part a¹ of the card board
also assisting to stiffen it. The whole is put into a die or press to compress
the rim or rib a around the edge and also to dish it so that the turned over
rim is sunk flush with the surface of the film. Pressing with hot dies will cause
the turned over part to adhere to the film; if not, resin or other adhesive
material may applied.
In each case breaks or cuts.b in the rim or rib a such as shown in Fig. 15, 16
& 17 may be made in the rim or rib to facilitate cutting and removal as in
many instances it will be found the stiffening rim or rib has served its purpose
after the film has been exposed developed waslied and dried and the rim can be
cut off by a pair of scissors knife or other convenient _tool.
There are many advantages in stiffened films made according to this inven-
tion. For instance if used for negative making they require no carriers or
any other of the usual means for keeping them flat when being used' in dark
slides, magazines, and the like. They are specially advantageous in many forms
of changing apparatus as the manipulation of the films therein is thereby
rendered as easy as and sometimes easier than glass plates. They are for
all practical purposes. as rigid as glass plates without the weight and fragility.
Then if used for lantern slides they require no cover glass or binding material
round the edges although such may be added if desired. If used as either
transparent or opaque positives they need no frame or mounting card: the
stiffening rim enables them to be placed in any position and gives .a finished
appearance. This latter may be still further enhanced by suitable masks or
borders which may consist of paper or other material attached to the film oi
embedded therein during manufacture or coloured pigment applied at any con-
venient time during manufacture or use.
For magazines and in other cases where the films are placed behind each
other and the front one exposed or for the purpose of preventing halation, I
make the back of the film opaque either by attaching a black paper thereto
or by the application of a coating of pigment; in either case the opaque backing
comes off as soon as the film is wetted or it can be stripped off by the operator
when dry. I use either of these methods in combination with a stiffened film..
I wish it to be understood that I am aware that the use of. a metallic frame
embedded in a gelatine film during the process of manufacture has been described
in the Specification of Planchon's Patent 14189 of 1890 but I do not consider
that such a method of stiffening films is practical.
. Having now particularly described and ascertained the nature of the said
invention and in what manner the same is to be performed I declare that what
I claim is: -
1. A photographic film stiffened by a rib or rim around the edge_substan-
tially as described and shown with reference to either of the figs. of the drawings.
2. In a photographic film stiffened by a metallic or other rib or rim around

page_text: the edge a break cut or notch formed therein to facilitate the cutting of the
rib or rim substantially as described.
3. A photographic film constructed with a stiffening rib around the edges in
combination with a removable opaque backing of paper pigment or other
material which will strip off on being wetted substantially as described:
Dated this 29th day of January 1900.
WM. P. THOMPSON & Co.,
Manchester, Liverpool and London, Patent Agents.