Improvements in Photographio Dark Slides.
Year: 1893

page_text: Date of Application, 8th Dec., 1893
Complete Specification Left, 1st Sept., 1894-Accepted, 10th Nov., 1894
PROVISIONAL SPECIFICATION.
Improvements in Photographio Dark Slides.
I GEORGE FRANCIS HORNE of 21 St. Johns Square Clerkenwell, London
Middlesex, Engraver on Wood do hereby declare the nature of this invention to
be as follows:-
:~
This invention, relates to an improved construction of dark slides for use in
photographic cameras. In carrying out my invention, I employ practically the
well known form of dark slide, but instead of using metal, wood, or wood bound
with metal, I use cardboard, millboard or other similar materials, thus reducing the
weight & cost to a minimum. I also make use of a new pattern of shutter, which
having a projection on each of its lower edges, catches against similar projections
as it approaches the top of dark slide, & thus forms a convenient stop, preventing
the said shutter from being drawn completely out.
Dated this 8th day of December 1893.
HADIY
GEORGE F. HORNE.
COMPLETE SPECIFICATION.
Improvements in Photographic Dark Slides.
1 GEORGE FRANCIS HORNE of 21 St. Johns Square, Clerkenwell, London,
Middlesex, Engraver on Wood, 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 improvements in the construction of dark slides for use
in photographic cameras.
In carrying out my invention 1 employ substantially the well known form of
dark slide, but instead of using metal, wood, or wood bound with metal, I use
cardboard, millboard or other similar material, thus reducing the weight and cost
to a minimum. I also make use of a new form of shutter, having projections on
each of its lower edges, which catch against similar projections on the frame of the
dark slide when the shutter is drawn, thus forming a convenient stop, preventing
the shutter from being drawn out completely.
DESCRIPTION OF THE DRAWINGS.
Figure 1 shows a front view of a double dark slide in its closed position.
Figure 2 is a front view, with the front frame B removed, showing the under
frame or strips C within which the shutter works, the shutter in this view being
shown withdrawn almost to its fullest extent.
Figure 3 is a vertical sectional view of the slide, when both shutters are fully
drawn.
Figure 4 is a cross sectional view of the slide, from side to side.
A, A' indicate the two shutters of the double dark slide, having projections I, I,
on their lower side edges (Fig. 2); these projections sliding between the outer
frame B and inner frame D, which frames are kept the necessary distance apart by
means of the strips C, which are provided with projections K at their upper ends
which engage with the projections I on the shutter, when the latter is drawn
outwards.

page_text: The centre frame E may be substantially the thickness of two sensitised plates
or films and may be constructed of separate strips or layers, or may be cut or
stamped from a single sheet of strawboard or millboard or similar material. The
thin frames D, D₁ which are cemented or attached to this centre frame are
substantially of the same size as it, except at the bottom, as shown at D* Figure 3,
where they slightly overlap, in order to prevent the sensitised plates from falling
out or forwards when the shutter is withdrawn, small catches or turn-buttons
being provided at the opposite end of the frame, to retain the top of the plates in
position.
The shutter A is shaped at its lower edge L Figure 2 in order that its outside
edges may enter first into the groove and therefore forming a species of wedge,
overcoming any tendency to bind or stop, should either of the mounts B or D have
become bent or injured and thus prevent the shutter A from going completely
home.
In order to increase the durability of the slides I may bind or cover the two side
edges and the bottom, with suitable binding material, as indicated at F, Figure 4.
To prevent the access of light to the interior of the slides between the back of
the shutters A, A' and the inner frames D, D' and E I glue or attach a strip of
chenille or similar material between the two shutters A, A, as shown in Figures 1,
2 and 3.
In order to prevent a shutter from being accidentally drawn, I may attach a
clip or catch H (Figure 1) to the top corner of the slide, so as to engage with the
top of the shutter, when in its closed position.
In constructing my improved dark slides the frames E and D, D', and strips C
are glued or cemented together in their proper positions, the shutters A, A are
then inserted in their places, and the outer frames B, B₁ then attached to the
strips C.
By these means I am enabled to produce a cheap, durable and light dark slide,
constructed entirely, or in part, of successive layers of leatherboard, strawboard,
millboard or other similar material; these layers, being formed by dies, cutters or
other means to the various required shapes, when glued, or fastened together,
themselves form the grooves, distance pieces, projections and other parts necessary
to make a light-tight case with moveable shutters, for holding, sensitised plates or
surfaces for use in photography.
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 :-
1. A photographic dark slide constructed of leatherboard, millboard, strawboard
or similar material substantially as described.
2. The construction and use of a photographic dark slide constructed wholly or
mainly of layers of leatherboard, millboard, strawboard, or other similar material,
cut by dies or cutters or other means to the required shapes and glued or otherwise
fastened together, so as to form the grooves, projections and other parts of a light-
tight case, with a connected moveable shutter-for holding sensitive plates for
photographic uses protected from light, and yet with capability of being exposed
at will, as set forth.
Dated the 31st day of August 1894
WM. BROOKES & SON,
55 & 56, Chancery Lane, London, Agents for the Applicant.