IMPROVEMENTS IN PHOTOGRAPHIC CAMERAS
Year: 1882

page_text: PROVISIONAL SPECIFICATION left by Edmund Edwards at the Office of
the Commissioners of Patents on the 15th August 1882. A communication
to him from abroad by Paul Rouaix, of Paris, in the Republic of France.
EDMUND EDWARDS, of the firm of Edwards and Co :-, Patent Agents and
Engineers, of 40, Southampton Buildings, Chancery Lane, in the County of
Middlesex IMPROVEMENTS IN PHOTOGRAPHIC CAMERAS" [A communication
to him from abroad by Paul Rouaix, of Paris, in the Republic of France]
"
This invention relates to photographic cameras, in which the operations of
sensitizing and developing the glass plate upon which a picture is to be obtained
are carried on in the camera itself, without the necessity for a separate dark
chamber.
The improved camera constructed according to this invention consists of a front
part and lens of any of the ordinary well-known kinds, and of a back part of novel
method of construction in which the desired operations are effected.
This part of the camera is provided at the back with a hinged door which can be
opened or closed as desired, and with a flat horizontal slide fitting below the top
of the camera and having a handle by which it can be drawn in or out as
desired.
Below this slide and near its front edge is arranged a groove provided with a
spring so that a separate ground glass for focussing can be readily inserted and
held in it, the moveable slide and glass being then pushed forward into their place
against a stop inside the camera, and the picture being then accurately focussed
upon the ground glass by means of a rack and pinion or other equivalent means in
the ordinary way, and the lens in them closed.
To sensitize the plate the ground glass is removed and a suitable plate, coated
with iodized collodion in the open air, is inserted and fixed.in its place.
The slide is then pushed forward against the stop already described, the
collodionized plate then hanging vertically over the centre of a suitable vessel
containing silver sensitizing solution, which is fitted into an opening in the bottom
of the camera. The back shutter is then closed, and the lens being already covered
no light can reach the interior of the camera.
The vessel containing the silver bath is then raised until the collodionized plate
is completely immersed in it, and it remains there until properly sensitized.
.

page_text: The vessel is then lowered, and the sensitized plate occupying exactly the same
position as that previously occupied by the ground glass, the lens is uncovered and
the plate exposed for a sufficient time, when the lens is again covered.
To develop the picture thus produced, the horizontal slide together with the
plate is drawn back against a catch in which position it is exactly above a second
vessel fitted into a second opening in the bottom of the camera, and containing a
suitable developing solution.
This second vessel is then steadily raised until the plate is completely immersed
in the solution where it remains for a sufficient time, and the vessel being then
lowered the back shutter is opened and the horizontal slide being drawn back the
plate carrying the developed picture is removed, and can be fixed or otherwise
treated as desired.
The vessels containing the baths may be made together or separate according to
the size of the apparatus, and they are guided by grooves in the sides of the camera,
and may be provided with moveable water tight covers so that the removal of their
contents is unnecessary.
Openings closed by hinged or other moveable covers provided with suitable
fastenings are made in the camera at the end of the openings in which the vessels
are fitted, so that the latter can be removed to be cleaned or re-filled when
necessary.