IMPROVEMENTS, IN PHOTOGRAPHIC CAMERAS to be as follows:-
Year: 1884

page_text: We WILLIAM SAMUEL ATWOOD of 1 Limo Tree Villas, Chaso Side, Southgate
in the County of Middlesex, Photographer and SAMUEL BENJAMIN GOSLIN of
27 Jewin Crescent Cripplegate in the City of London Engineer do hereby declare
the nature of our invention for ".IMPROVEMENTS, IN PHOTOGRAPHIC CAMERAS
to be as follows:-
"
In our improved photographic camera we employ a dark slido receiving two
sensitive plates back to back and we enclose the frame which receives these plates
in a cover or sheath which surrounds it on all sides and is open only at the bottom.
When the slide is in the camera this sheath being withdrawn both the plates are
uncovered simultaneously, but one only of the plates is exposed to the light viz
the one which is properly placed in the focus of the lense the other being protected
as hereinafter described.
By the use of this sheath like cover we are able to make double slides or dark
slides receiving two sensitive plates much smaller more cheaply and effective than
heretofore.
For the withdrawal of the sheath a button is provided upon it at the top and
the same button being made to turn serves to lock the sheath to the frame in
which the plates are held.
Whilst focussing and when the dark slide is out of the camera the focussing
glass-is held by springs against the end of the dark chamber.
To prepare for the insertion of the dark slide the lower edge of the focussing
glass is drawn back for a distance somewhat more than the thickness of the dark
slide and is inserted into a groove in the base of the camera which serves to
retain it. The dark slide is then pushed down between the focussing glass and the
end of the dark chamber of the camera into the place previously occupied by the
focussing glass The focussing glass is then lifted at the bottom to release it from
the groove and a stud pin upon it then enters a hole in the frame carrying the
sensitive plates and locks it in its place. The dark slide being in its place ready
for the exposure of one of the plates all that is then required is to unlock and
draw off the sheath. The frame carrying the plates remains in the camera, being
held as already explained and the springs hold it closely up to the end of the dark
chamber. The focussing glass is prevented from rising with the sheath of the dark
slide by shoulder pieces beneath which its upper edge passes when it is pressed
back by the insertion of the slide in front of it.
Light is prevented reaching the sensitised plate which is uncovered at the back
of the dark slide by a shutter like door which is closed over the focussing glass
when, this is not in use. This door or shutter effectually prevents the entrance of
light into the camera through the focussing glass.
Dated this 7th day of June 1881
CARPMAEL & Co.,
Agents for the Applicants.

page_text: COATLEIE SPECIFICATION.
We WILLIAM SAMUEL ATWOOD of 1 Lime Tree Villas, Chase Side, Southgato
in the County of Middlesex Photographer and SAMUEL BENJAMIN GOSLIN of
27 Jewin Crescent Cripplegate in the City of London Engineer do hereby declare
the nature of my invention for "IMPROVEMENTS IN PHOTOGRAPHIC CAMERAS
and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement :-
"
In our improved photographic camera we employ a dark slide receiving two
sensitive plates back to back and we enclose the frame which receives these plates
in a cover or sheath which surrounds it on all sides and is open only at the bottom.
When the slide is in the camera this sheath being withdrawn both the plates aro
uncovered simultaneously but one only of the plates is exposed to the light,.viz,
the one which is properly placed in the focus of the lense the other being protected
as hereinafter described.
"
By the use of this sheath like cover we are able to make double slides or dark
slides receiving two sensitive plates much smaller more cheaply and effective than
heretofore.
For the withdrawal of the sheath a button is provided upon it at the top and
the same button being made to turn serves to lock the sheath to the frame in which
the plates are held.
Whilst focussing and when the dark slide is out of the camera the focussing
glass is held by springs against the end of the dark chamber.
To prepare for the insertion of the dark slide the lower edge of the focussing
glass is drawn back for a distance somewhat more than the thickness of the dark
slide and is inserted into a groove in the base of the camera which serves to retain
it. The dark slide is then pushed down between the focussing glass and the end
of the dark chamber of the camera into the place previously occupied by the
focussing glass. The focussing glass is then lifted at the bottom to release it from
the groove and a stud pin upon it then enters a hole in the frame carrying the
sensitive plates and locks it in its place. The dark slide being in its place ready
for the exposure of one of the plates all that is then required is to unlock and
draw off the sheath. The frame carrying the plates remains in the camera being
held as already explained and the springs hold it closely up to the end of the dark
chamber. The focussing glass is prevented from rising with the sheath of the
dark slide by shoulder pieces beneath which its upper edge passes when it is
pressed back by the insertion of the slide in front of it.
Light is prevented reaching the sensitised plate which is uncovered at the back
of the dark slide by a shutter like door which is closed over the focussing glass
when this is not in use. This door or shutter effectually prevents the entrance of
light into the camera through the focussing glass.
In order that our said invention may be most fully understood and readily
carried into effect we will proceed to describe the drawings hereunto annexed.

page_text: Figure 2 is a similar view of tho rear part of the camera but with the dark
slide containing a pair of sensitive plates in position in the camera. The door
covering the focussing glass is closed so that the dark slide may be opened without
exposing the sensitive plates which it contains to any light other than that which
enters the camera from the lenso in front. The dotted lines in this figuro show the
sheath of the dark slide partly raised.
Figure 3 shows in transverse section and partly in perspective elevation the
dark slide constructed in accordance with our invention. This dark slide consists
of an open rectangular frame the top and bottom rails of which are represented
in section at A¹ and A. The lower rail A³ is thicker than the upper rail and the
side rails and it is grooved to receive the lower edges of the sheath. The sheath
may be made of wood cardboard or sheet metal or any light thin and opaque
material. It consists of sidos B B and ends which do not appear in the figure
except in the dotted position in Figure 2 where one of the ends is marked B'.
The sheath completely surrounds the frame A' A' and its lower edges enter into
grooves in the lower rail A' of this frame and there fit closely so as to exclude all
light. The sheath is closed at the top by a piece B fixed into it and which
conveniently may be of wood.
C¹. C² represent two glass plates suitably prepared as usual with films sensitive
to light, they are preferably "dry" photographic plates. Between them there is a
zinc plate D to prevent light passing through the front plate reaching the plate in
rear. These plates are kept in their places in the frame A¹ A by four turn
buttons two at the top and two at the bottom on one side of the frame and four
corresponding fixed lugs on the other side of the frame. E is a turn button it is
of wire and passes through the top B³ of the sheath. The lower end of the wire E
is bent horizontally at right angles and it is adapted to enter between two small
brass plates fixed on to the top of the rail A. The rail is recessed to allow it to
enter and so that when the lower end of the turn button E is between the plates
it can turn partly round so that its horizontal end may enter beneath one or other
of these two plates. In this position the turn button locks the sheath to the
frame A¹ A but by a turn of the button the sheath can be unlocked and it can
then be drawn up entirely off and away from the frame A¹ A² so as to expose the
plates which it contains.
The upper edges of the rail A¹ it will be seen are bevelled to enable the sheath
to pass on readily.
Such then being the construction of the dark slide the end of the dark chamber
of the camera is so formed that the slide when without its sheath may fit closely
up to it in such a manner as to exclude light. The sides of the camera are rabbeted
or recessed at the lower part to receive the additional thickness of the lower rail
of the dark slide.
F F are two angular guides fixed upon the camera, they form an extension of the
camera body open at the top but closed by these guides on the sides and also
closed at the bottom. Thus a holder is formed for the frame G in which the
focussing glass is set and to receive the dark slide. This frame G with the focussing
glass is formed to fit up to the end of the chamber of the camera in the same way
as the dark slide in which the sensitive plates are carried. The focussing glass is
pressed forward to its position by the springs H H one on either side fixed to the
angle guides F.
•
This frame with the focussing glass differs from the corresponding part in cameras
at present in use in that it is provided with a door G' which when shut closes the
back of the camera light tight. Turn buttons are provided to keep the door closed
as is clearly seen in the figures.
G G. are handles at the top and bottom of the frame of the focussing glass by
which it is conveniently moved in the use of the apparatus. A rib or projection is
formed along the bottom of the frame G and a corresponding groove I is formed
in the bottom of the camera; 'this is for the purpose of keeping the bottom of the
frame G away from its face. When this required the focussing glass is drawn

page_text: back by means of the lower handle G2 and the projecting rib upon it is caused
to drop down into the groove I which then retains the frame G against the pressure
of the springs H H. This is the position to which the frame G is brought after
focussing and preparatory to the introduction of the dark slide. The upper end of
the frame G is next drawn back by means of the upper handle G' leaving a space
between the frame G and the top of the camera chamber. Into this space the
dark slide is then dropped and when it is down the frame G is released from the
groove I by lifting it slightly. The springs H then force forward both the frame G
and the dark slide in front of it but the dark slide does not go quite home to its
placo being prevented from doing so by the thickness of the sheath which is still
upon it. In this position pins however upon the frame G at its lower part enter
corresponding holes in the rail A2 and lock the two frames together. The frame G
also cannot now rise up in the guides F F for it is prevented from doing so by
shoulders G. G³. upon it which when the frame G is displaced by the insertion of
the dark slide in front of it enter beneath corresponding shoulders F¹ on the
guides F. The next operation now is to remove the sheath to expose one of the
sensitive plates and to permit tho image formed by the lense of the camera to fall
upon its surface. For this purpose the button E is first turned so as to release the
rail A¹ of the dark slide and then the sheath is drawn completely off and takeń
away. When the exposure is complete and the cap of the camera has been replaced
the operations are performed in the reverse order-the sheath is replaced (the
edges being bevelled to allow it to pass on freely) then the frame with the focussing
glass is drawn back at the bottom and dropped down into the groove I and
finally the dark slide is lifted out the sheath having previously been securely
locked in its place.
Having now particularly described and ascertained the nature of our said
invention and in what manner the samo is to be performed we declare that what
we claim is
"
1. A camera having a dark slide with a sheath completely surrounding a pair of
sensitive plates which sheath when drawn off leaves both plates uncovered
substantially as herein described.
2. A camera capable of being closed at the back behind the focussing glass by a
door and in combination therewith a dark slide carrying a pair of sensitivo plates
which are covered and uncovered simultaneously substantially as described.
3. Our improved photographic camera substantially as described and represented
by the Drawings annexed.