An Improved Dark Slide for Photographic Cameras and Improve- ments in Cameras to be Used, therewith.
Year: 1888

page_text: Date of Application, 12th Apr., 1888
Complete Specification Left, 7th Feb., 1889
Complete Specification Accepted, 9th Mar., 1889
An Improved Dark Slide for Photographic Cameras and Improve-
ments in Cameras to be Used, therewith.
I, ANKETELL MATTHEW HENDERSON of 20 Avoca Street South Yarra in the
Colony of Victoria, Civil Engineer do hereby declare the nature of this invention to
be as follows:-
My invention consists first and mainly of an improved dark slide for photographic
cameras and secondly of certain improvements in such cameras to be used in
connection with my dark slide although such slide can be used with any kind of
square bellows camera or any box or detective camera of sufficient depth.
The dark slide consists of a flat box or tray containing a number of carriers or
frames for holding the sensitive plates or films. These carriers or frames can be
made of metal, cardboard wood or other suitable material. Each carrier or frame
is hinged on a pin which passes through the sides of the box or tray and has at
one end a bent arm or other contrivance by means of which the carrier or frame
inside can be swung or partially revolved and these pins are so arranged that each
plate can be swung or revolved about ninety degrees. This is done by arranging
the line of pins at an angle about forty-five degrees with the ends. of the dark slide
which is fitted with the usual sliding or folding shutter which can be opened when
the slide is in position in the camera and this shutter if sliding may be made to
remove altogether from the dark slide, and to hold it when so removed I provide
small clamps on the back of the dark slide. The dark slide may be made to slide
into grooves in the back of the camera or to slip between the ground glass and the
camera back or to fix to the back with clamps as may be found most convenient or
the dark slide may be made of sufficient depth to forin a box camera. The dark slide
is used as follows-
When the sliding or folding shutter is removed the exposure of the front plate is
made in the camera in the usual manner. This plate then by means of the bent arm
on the pin is turned at right angles into the body of the camera thus presenting the

page_text: back and edge of the carrier or frame to the lens and exposing the sensitive plate or
film in the next carrier or frame. Before exposing this film the lens or dark slide
must be brought nearer to the extent of the thickness of the carrier or frame. To do
this accurately I use a scale on the sliding part of the camera or on the lens the lines
on which correspond with the thickness of the carriers or frames. For detective
cameras where focussing is performed by estimating the distance of the view or object
from the camera I use a double scale the division of the one corresponding with the
thickness of the carriers or frames and the divisions on the other representing the
alterations of focal lengths at the varying distances of the view or object. These are
fitted to the sliding body of the camera or to the lens as may be most convenient so
that by bringing the line representing the distance in conjunction with the line
representing the plate or film whose surface is exposed the image cast by the lens on
the surface will be in focus.
To provide against the access of light to the edges of the plates when the
carriers or frames are turned out into the body of the camera, I use a shutter hinged
to a pin passing through the front of the camera and fitted with a bent arm or other
contrivance by means of which the shutter can be hinged or revolved so as to cover
the backs and edges of the carriers or frames and prevent access of light to the
edges and this shutter can be made with the edges turned back like an inverted tray
for greater security. Where the lens projects inside the front of the camera I make
the centre of this shutter of pliable material. To further protect the plates from
light I line the inside of the dark slide and the portion of the camera into which the
plates project with velvet or similar material and when the dark slide is made for
use in a bellows camera I hinge in front of the front carrier or frame a tray which
can be turned out into the body of the camera to enclose the plates or carriers when
so turned out.
To hold the carriers or frames in their places in the dark slide parallel to each
other I use various contrivances. For small plates or films I use an arm fitted with
a spring and hinged to a pin passing through one end of the dark slide and fitted with
a bent arm or stud for partially revolving same. When the arm is turned out into
the camera each plate in turn can be released and the spring forcing back the arm
against the remaining carriers or frames will hold them in position. Another method
is to have a catch plate of wood or metal covered with velvet or similar material at
one end of the dark slide held in contact with the carriers or frames by a spring. This
catch is attached to a pin passing through the end of the dark slide so that it can be drawn
back when desired to release the carriers or frames. I use sometimes V-shaped studs or
a rack on the bottom of this catch plate to hold the carriers in exact position. For large
plates or films I prefer a similar catch plate for each carrier or frame each fitted with a
pin passing through the end of dark slide and arranged over each other so that raising
an inner catch will raise all the outer ones also. As before mentioned the dark slide
can be used in any square bellows camera or box or detective camera of sufficient
depth but I prefer to use one of the special cameras hereafter described.
For a detective camera I use a sliding box camera and place the sensitive plates
or films in the carriers or frames so that their centres are in a line parallel with the
sides of the camera. Where a lens of short focus is used I project the portion of the
camera front into which the carriers project so as to allow room for them.
For travelling cameras 1 place the plates or films in the carriers with their centres
parallel with the centres of the pins on which the carriers revolve and I carry the lens
on a front which moves parallel to these pins. In the first camera this is done by
attaching the front to parallel links and holding it at the correct focal distance by a
link attached to the top with lines marked thereon or holes bored therein at distances
corresponding with the various films or plates. In the former case the double scale
already described is used in the latter case a pin on the top of the camera is provided
which fits into the holes and thus holds the front at a correct focal distance.
This
pin can be made to slide so as to adjust the front for varying distances of the view
or object. The rest of the body of the camera 1 make of pliable leather or cloth or
India rubber cloth.

page_text: In the second camera I use the lower part of the front is hinged to the upper and
opens parallel to the line of pins of the carrier or frames. The lens is fixed in a
sliding plate on the front fitted with a double index as before described.
part of the body I make of leather cloth or similar material.
The lower
Dated this Ninth day of March One thousand eight hundred and eighty-eight.
ments in Cameras to be Used therewith.
I, ANKETELL MATTHEW HENDERSON, of 11, Elizabeth Street, in the City of
Melbourne, in the Colony of Victoria, Architect and Licensed Surveyor, do hereby
declare the nature of this invention and in what manner the same is to be per-
formed to be particularly described and ascertained in and by the following
statement :-
My invention consists firstly and mainly of an improved dark slide for photographic
cameras to hold a number of sensitive plates or films and secondly of certain improve-
ments in such cameras to be used in connection with my dark slide although such
slide can be used with any kind of square bellows camera or any box or detective
camera of sufficient depth.
In order to enable my invention to be fully understood I will describe how it
can be carried into practice by reference to the accompanying drawings, in which
Figure 1 is an elevation of the outer side of my improved dark slide.
Figure 2 is a cross section through the ends of the dark slide.
Figure 3 is a horizontal section through the sides of the dark slide.
Figures 4, 5, 6 & 7 show various arrangements of scales for the purpose of
focussing.
Figures 8, 9, and 94 are sections showing alternative arrangements for holding the
frames or carriers in position.
Figures 10 and 11 are sections through the box of my detective camera specially
designed for use with the improved.dark slide.
Figures 11 and 13 are vertical sections showing two new forms of portable
cameras specially designed for use with my improved dark slide.

page_text: Figure 12 is a horizontal section of nigure 11.
In all the figures of the drawings, I have used similar letters to denote similar
parts.
The dark slide A, figures 1, 2, and 3, consists of a flat box or tray containing a
number of carriers 1, 2, 3, 4, 5, 6, for holding the sensitive plates or films. These
carriers or frames must be made of some stiff material such as metal, cardboard, or
wood. Each carrier or frame is hinged on a pin B which passes through the sides of
the box or tray and has at one end a bent arm C or other suitable contrivance by
means of which the carrier or frame inside can be swung or partially revolved
and these pins are so arranged that each plate except the back one can be swung
or revolved to the extent of about 90°. This is done by arranging the line of
pins at an angle of about 45° with the ends of the dark slide which is fitted
with the usual sliding or folding shutter D which can be opened when the slide is in
position in the camera and this shutter when arranged to slide may be made so
that it can be removed altogether from the dark slide and hold it when so removod,
I provide small clamps on the back of the dark slide.
The dark slide may be
arranged to slide in grooves in the back of the camera or to slip between the
ground glass and the camera-back or to be fixed to the back with clamps as may
be found most convenient; or the dark slide may be made of sufficient dopth to
form a box camera and be fitted with a lens &c.
The dark slide is used as follows:-
When the sliding or folding shutter is removed the exposure of the front plate
is effected in the camera in the usual manner. This plato then by means of the
bent arm on the pin B is turned at right angles into the body of the camera
as shown by the dotted lines in figure 2, thus presenting the back of the carrier
or frame 1 to the lens and exposing the sensitive plate or film in the next carrier 2.
Before exposing this film, the lens and dark slide must be brought nearer to the
extent of the thickness of a carrier or frame. To do this accurately I use a scale
on the sliding part of the camera or on the lens the lines on which correspond
with the thicknesses of the carriers or frames. For detective cameras when
focussing is performed by estimating the distance of the view or object from the
camera I can make use of various contrivances. One of these contrivances, as shown
in figures 4 and 5, consists of a double scale the division of one of the scales F
corresponding with the thickness of the carriers or frames and numbered to correspond
with such carriers or frames. The divisions on the other scale G represent the
alterations of focal lengths at the varying distances of the view or object. These
scales are fitted to the sliding and fixed parts respectively of the camera or the lens
as may he most convenient so that by bringing the line representing the distance to
correspond with the line representing the plate or film whose surface is exposed the
image cast by the lens on the surface will be in focus. I can also arrange the scale F
to slide, as shown in figure 6, or to rotate, as shown in figure 7, so that the said scale F
can be set for a particular plate or film by sliding or rotating the scale, the focussing
being effected by bringing the index thereon to correspond with the line representing
the distance on the scale G.
To hold the carriers or frames in their places in the dark slide parallel with each
other, I can use various contrivances. For small plates or films I find it advantageous
to use the arrangement illustrated in figure 8, in which an arm I with a stud on the
end is fitted with a spring and is hinged to a pin J passing through one end or side
of the dark slide and fitted outside the slide with a bent arm or stud for partially
revolving the same. When the arm is turned out into the camera each plate in turn
can be released and the spring forcing back the arm against the remaining carriers or
frames will hold them in position.
Another means for arriving at a similar result is illustrated in figure 9. In this
arrangement I employ at one end of the dark slide a catch plate K of wood or metal
covered with velvet or similar material and held in contact with the carriers or frames
by means of a spring. This catch is attached to a pin L passing through the end of
the dark slide so that it can be withdrawn when desired to release the carriers or

page_text: frames, the bottom of the catch plate K being provided with V-shaped studs or a rack
to hold the carriers in exact position. For large plates or films I prefer to employ a
separate catch plate for each carrier or frame as shown at M in figure 9 each catch
plate being fitted with a pin passing through the end of the dark slide and arranged
one above the other so that by raising an inner catch all the outer ones will be also
raised.
I sometimes make the dark slide wider than the carriers and fix projecting studs on
one of the inner sides to catch cach carrier. By pulling or pushing the pins B and
the bent arm C the carriers or frames can be moved sideways clear of the projecting
studs on the side and swung into the camera.
To prevent the access of light to the edges of the plates when the carriers or frames
are turned into the body of the camera, I use a cover or flap II (as shown in figure 10)
hinged to a pin passing through the sile near the front of the camera and fitted with
a bent arm or other contrivance by means of which the cover or flap H can be swung
or revolved so as to cover the carriers or frames and prevent access of light to the
edges. The cover or flap H can be fitted with a spring or made with the edges
turned back like an inverted tray for greater security.
Where the lens projects inside the front of the camera, I make the centre of the
cover or flap H of flexible material.
Where an instantaneous shutter is used in the front of the camera, I enlarge the end
of the bent arm or other contrivance so as to cover the trigger of the instantaneous
shutter so that exposure cannot accidentally be made when the inside cover or flap is
not open.
To further protect the plates from light, I line the inside of the dark slide and the
portion of the camera into which the plates project with velvet or similar material
and, when the dark slide is intended for use in a bellows camera, I binge in front of
the front carrier or frame a tray which can be turned into the body of the camera to
enclose the plates or carriers when so turned.
As before mentioned the dark slide can be used in any square bellows camera or
box or detective camera of sufficient depth but I prefer to use one of the cameras
constructed as hereinafter described, these cameras being all fitted with lenses, finders,
and instantaneous shutters as usual.
For a detective camera I advantageously use a sliding box camera N, figures 10
and 11, and I place the sensitive plates or films in the carriers or frames so that their
centres are in a line parallel with the sides of the camera. Where a lens of short
focus is used, I extend a portion of the camera front, as shown at O, so as to allow the
ends of the carriers to project beyond the said front. I prefer also to arrange the
sliding shutter of the dark slide to remove from that side of the dark slide through
which the bent arm projects and I find it advantageous to form in the side of the box
camera a small sliding or folding door P to allow of the insertion of the dark slide
and to afford access to the shutter and bent pins thereof.
Sometimes I make the outer box large enough to hold one or more extra dark
slides at the back as indicated by the dotted lines in figures 10 and 11.
For portable or travelling cameras, I place the plates or films in the carriers with
their centres parallel with the centre of the pins on which the frames or carriers
revolve, as shown in figures 114, 12 and 13, and I carry the lens on a front which
moves parallel with these pins. In one arrangement of camera shown in figures 11ª
and 12 this is effected by attaching the front T to parallel links RR and holding it
at the correct focal distance by means of another link S attached to the top of
the front and having lines marked thereon or holes bored therein at distances
corresponding with the various films or plates. In the former case the double scale
already described is used and in the latter case a pin U on the top of the camera is
provided which fits into the holes and thus holds the front at a correct focal distance.
The pin U can be arranged to slide on a scale similar to that shown at G in figures 4
to 7, so as to adjust the front to the various distances of the views or objects.
The rest of the body of the camera I make of pliable material such as leather or cloth
or india rubber cloth.

page_text: In another arrangement of camera shown in figure 13, the lower part of the front
is hinged to the upper part and opens parallel with the lines of pins of the carriers
or frames. The lens is fixed in a sliding plate Won the front fitted with a double
index or a brass plate with holes as before described. The lower part of the body I
make of pliable material such as leather cloth.
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). In dark slides for photographic cameras the use of several film or plate-carriers
or frames hinged on separate pins and fitted with bent arms or other suitable means
whereby the films or plates can be turned into the body of the camera, substantially
as herein before described.
(2). In a photographic camera the use of the double scales for focussing as described
and the sliding and rotating arrangements thereof illustrated in figures 4 to 7 of
the accompanying drawings.
.
(3). In a photographic camera, the inside cover or flap for protecting the plates
when turned into the camera and the arrangement for preventing accidental exposure
when such cover or flap is not open, substantially as hereinbefore described.
(4). In dark slides for photographic cameras, the arrangements of revolving arm
and catch plates for holding the carriers or frames in parallel position, substantially
as herein before described and illustrated in figures 8, 9 and 9ª of the accompanying
drawings.
(5). In dark slides for photographic cameras, the herein described arrangement for
allowing a lateral movement of the carriers or frames.
(6). A sliding box camera having a sliding door or shutter at the side and adapted
for use with lenses of short focus, substantially as hereinbefore described and illustrated
in figures 10 and 11 of the accompanying drawings.
(7). A portable camera having its front hinged or connected by links so that the
lens shall move parallel with the centres of the sensitive plates and pins substantially
as hereinbefore described and illustrated in figures 114, 12 and 13 of the accompanying
drawings.
Dated the 7th day of Wohnune 1000