Patent GB-190701404-A (GB)
Title: Improvements in and relating to the Daylight Production of Photographic Negatives from Dry Plates or Cut Films.
Inventor: WISHART GEORGE
Filed: 1907-01-19
Granted: 1908-01-16
Abstract: 1404. Wishart, G., and MacKenzie, F. Jan. 19. Cameras; change-boxes; trays and dishes.-Relates to apparatus for carrying on in daylight, as far as the completion of developing, the process of producing negatives from dry plates or cut films. A cell 13, Fig. 5, having a thin sliding door 15 and containing either plates, or films in sheaths, is placed in the back of the camera, and held against a sliding frame 6 by a spring 4 which passes through a hole 14 in the back of the cell and presses against a dummy end plate 54. When the sliding door 15 is drawn up, the plates are advanced by the spring, so that one plate is cut off ready for exposure when the door 15 is returned ; the sliding frame 6 is then drawn up and the plate is tilted into another cell 13, similar to the other, and inserted at the bottom of the camera to receive the exposed plates. The dummy 54 is retained upright by an extension on its top edge. For development, the lid is slid on the lower cell in the camera, and the cell is removed through either the front or back door. It is then slid, with the cover 15 downwards, on to a developing-box 38, Fig. 15. One plate is cut off by drawing out and then replacing the cover 15, the plate falling on to the developing- box cover preferably of ruby glass, celluloid or the like &c. ; on drawing out this cover, the plate falls into the dish 41. The dish rests on the base, preferably slidable and of ruby glass &c. and receives the developer, and later the washing-water, through a filler and three-way cock, which also allows rejected fluid to be drawn off. The dish may be covered at one end to allow tilting for examination of the plate during development. Another cell may be used alternatively with the one containing exposed plates to drop wire frames into the developing-dish, thus keeping the plates apart when more than one are developed at once. Another method of allowing the plates to fall in the camera consists in having, instead of the sliding frame 6, an oscillating frame, worked by a handle outside and turning on an axis in the fore part of the camera-roof. This holds back the upper edge of the plate, till rotated downwards. A spring roller blind may cover exposed plates in the camera during focussing. An auxiliary refill for use within the dark cell may be constructed as a box with sliding cover, the bottom having a hole to allow the spring 4 to act on the dummy end plate in the box, the first plate also being a dummy. Before irisertion in the cell, the cover is removed, but the pack is held together by tapes passing round notches in the box, drawn off when the latter is in the cell. Or instead of placing the box in the camera within a cell such as 13, the cell may be dispensed with, and the cutting-off door 15 fitted to the camera behind the reciprocating frame 6. Sheaths may be made of paper reverted on three sides and pressed to a sharp edge at the bottom, tongues being gummed over the top corners from the front edges to the back. If the camera cannot be tilted to cause the plates to fall into the lower cell after exposure, the door of the upright cell may have a spring to throw the plates forward.