Improvements in and relating to Photographic Cameras and Dark Slides.
Year: 1888

page_text: 1. Date of Application, 8th May, 1888
Complete Specification Left, 7th Feb., 1889
Complete Specification Accepted, 30th Mar., 1889
PROVISIONAL SPECIFICATION.
Improvements in and relating to Photographic Cameras and Dark
Slides.
1
I, SAMUEL MARK CLARK of No. 54 Cheapside, London, E.C. Secretary to
a Public Company, do hereby declare the nature of this invention to be as
follows:-
This invention has for its object the construction of photographic Cameras in
such a manner as to ensure strength and portability, combined with the highest
efficiency, at the same time that it shall be selfcontained.
The device according to my invention comprises a box or case serving as a
Camera perforated centrally in front to receive the object lense, and furnished at
the back with a closely fitting hinged door and suitable fastening. A metal flanged
collar is secured within the perforation above referred to, into which takes the object
lense, and which is held firmly in position preferably by a bayonet-joint forming part
of the lense tube.
In the roof of the box or case forming the camera is an opening in which is
fitted a ground glass screen, beneath which is an enclosed chamber provided at the
back thereof with a mirror fixed perferably at an angle of 45 degrees. A second
auxilliary object lense is inserted in the front of the camera immediately above the
object lense proper, and centrally with the enclosed chamber aforesaid. A flat cover
having folding side walls shuts down upon the ground glass screen, and is held in
position by a suitable bolt, catch or equivalent, and in order to ensure a rapid opening
of the cover, a spring or piece of elastic is secured to the box and to the cover
aforesaid.
An instantaneous shutter, which is pivoted within the box or case, is actuated by a
slide, bolt or equivalent passing through the side thereof, which, being drawn out
against the tension of a spring, is caught and held back by a suitable spring catch;
provision being made to vary the tension of said spring and thereby the speed at
which said shutter closes.
The dark slide devised to be used in combination with the improved camera
according to my invention consists of a frame having a central partition of any

page_text: suitable material, preferably a web of woven fabric treated with any convenient
substance to render it light proof. By this means I am enabled to enclose two plates
in one slide, said plates being held rigidly therein by suitable clamps, bolts or equiva-
lent. An enclosing case or envelope is provided which accurately fits and encloses
the dark slide, and is held firmly upon said slide by two small springs inserted in
the sides thereof.
When packed for travelling, the object lense is secured in the interior of the camera
by suitable clamps, and the auxiliary lense, in its telescopic tube, pressed in so as to
lie nearly flat with the front of the camera. Three dark slides are provided, two
being placed in the camera, one on each side, and held in position by suitable guides,
the third slide being at the back of the camera in the position it would hold when an
object is to be photographed. A suitable handle is attached to one side for convenience
of carriage.
In using the apparatus, the object lense is removed from the interior and secured to
its collar by the bayonet-joint-like attachment, and the shutter and cover in the roof
opened, the object being now projected upon the two ground glass screens, the
lenses are adjusted and the apparatus is ready for use, the sensitive plate being
exposed by the withdrawal of the enclosing case of the dark slide from beneath
the camera.
The auxilliary lense and enclosed chamber in the upper part of the camera is
devised to ensure accuracy of the focal adjustment, it follows therefore that after the
first adjustment of the lenses, no further adjustment of the object lense is necessary,
if the object projected by the mirror upon the screen in the roof of the case exhibits
a sharp well defined outline.

page_text: COMPLETE SPECIFICATION.
Improvements in and relating to Photographic Cameras and Dark
Slides.
I SAMUEL MARK CLARK of 54 Cheapside, London E.C. Secretary to a Public
Company 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 has for its object the construction of Photographic Cameras in such
a manner as to ensure strength and portability combined with the highest efficiency,
at the same time that it shall possess the important feature of being self contained,
inasmuch as provision is made for the disposal of two or more dark slides within the
camera, each slide being arranged to contain two plates, thus ensuring to either
amateur or professional Photographists a perfect equipment, comprising all the
requisites for obtaining several views.
Referring to the accompanying drawings which form part of my Specification,
Figure 1 represents a sectional elevational view of a Camera showing the arrangement
of the different parts with the object lens in the interior when packed for carrying;
Figure 2 shows a cross sectional elevational view of same drawn on line A B Figure 1.
Figure is a plan of the upper exterior surface of the Camera, and Figures 4
and 5 are respectively an elevational view and sectional elevational view of a dark
slide.
The device according to my invention comprises a box or case a of any suitable
material, serving as a camera, perforated centrally in the front to receive a flanged
collar c', in which takes or is supported the object lens c secured by a bayonet joint or
equivalent means; the back of said camera being provided with a closely fitting
hinged door 6 having a suitable fastening.
In the roof of the camera a is an opening e in which is fitted a ground glass screen,
beneath which is an enclosed dark chamber f, provided at the back thereof with a
mirror m fixed preferably at an angle of 45 degrees.
is
A second auxilliary object lens d sliding telescopically in tube d' is disposed
centrally with the dark chamber f, in the front of the camera a and immediately above
the object lens c above mentioned. Above the screen e aforesaid is provided a flat
hinged cover g having folding side walls gl Figure 2. Said folding cover g
maintained in an open or extended position by means of a spring, piece of elastic or
equivalent which is secured to the top of the camera and to the folding cover g
aforesaid, which latter when folded flat upon the top of the camera is retained by a
catch, bolt or equivalent i.
.
The auxilliary lens d and dark chamber would, under some circumstances, be
employed as a finder, and to ensure accuracy in the focal adjustment; thus, having
adjusted the object lens in the ordinary manner, and inserted the dark slide con-
taining the sensitised plate or plates, the figures in the view or picture to be

page_text: photographed may have their positions varied to suit different circumstances, said
changes being observed on the screen e of the dark chamber and thus rendering
unnecessary the removal of the obscuring cap of the object lens.-Instead of
employing two different lenses as above described, capable of independent manipula-
tion, I may adapt to my improved camera two similar lenses, which, by means of
pinions carried upon a single spindle would engage with a rack formed upon each of
the lens tubes, by which means said two lenses could be focussed simultaneously, thus
rendering the removal of the obscuring cap of the object lens, for the purpose of
focussing, unnecessary.
Under this last above described arrangement, I am enabled by removing the
angularly disposed mirror m and employing a dividing web or wall within the
camera a of converting said camera into a stereoscopic camera.
Within the camera a is pivoted on the front thereof an instantaneous shutter k,
preferably of aluminium, having a suitable aperture formed therein.
Upon a grooved pulley 1, mounted upon said shutter k, is secured and wound a
thread, fine cord or the like n of some suitable non-elastic and non-extensible material,
the free end of which, passing over a second small pulley n', is secured to a small
bolt, rod or equivalent p, which latter, moving in suitable guides, passes through the
left wall of the camera a terminating in a knob or button p³.
In drawing out the rod or bolt p aforesaid for the purpose of rotating the shutter k
to bring the aperture coincident with the object lens, it is opposed by the tension of
a spiral spring or equivalent r, one end of which is attached to the grooved pulley /
aforesaid, the other end of said spring being secured to the interior of the camera
by any suitable means.
餐
When the rod p has been drawn out to its full extent, it is caught and held in the
extended position by means of a spring, catch, or equivalent v taking into a recess or
slot formed in the rod p aforesaid. On releasing the catch above mentioned the
rod p is, by the contraction of the spring ", caused to resume its normal position, the
shutter k being simultaneously instantaneously closed. Suitable provision is made to
vary the tension of the spring and thereby the speed at which the shutter k
closes.
The dark slide Figure 4, devised to be used with my improved camera, consists
of a frame having a central partition of any suitable material, preferably a web of
woven fabric treated with any convenient substance to render it impervious to light.
By this means I am enabled to enclose two sensitised plates in one dark slide, said
plates being retained rigidly therein by suitable clamps, bolts or equivalents. An
enclosing case or envelope y is provided, which accurately fits over said dark slide x
and is held firmly thereupon by two small flat springs inserted in the sides thereof.
When the improved camera in its initial form is packed for transport the object
lens is secured, as shown in Figure 1, in the interior thereof by suitable clamps t,
and the auxiliary lens in its telescopic tube pressed in so as to lie nearly flat with the
front of the camera. Two or
more dark slides ³r Figure 2, for carrying the
sensitised plates are provided, and disposed one at the back adjacent to the hermetically
closed door b, the other being secured to the sides within the camera, and retained
therein by any suitable means.
A suitable handles is attached to one side of the camera for convenience of
transport.
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
First: In a Photographic Camera the adaption thereto of an auxiliary dark chamber
and auxiliary lens substantially as and for the purposes set forth and shown.
Second-The combination with the auxiliary dark chamber and auxiliary lens of
a mirror for reflecting the image or object upon a focussing screen substantially as
described:

page_text: Third-In a Photographic Camera the combination therewith of the instantaneous
shutter substantially as herein described and the mode of and means employed for
actuating same substantially as and for the purpose herein set forth and shown.
Fourth-The utilisation of the interior of the box or case serving as a camera for
depositing therein the various accessories for the purpose of transport substantially
as herein set forth.
Fifth-The improved Photographic Camera and arrangement of the various parts
and accessories substantially as herein described and illustrated in the accompanying
drawings.