Patent GB-684596-A (GB)
Title: Improvements in or relating to photographic processing and apparatus therefor
IPC: G03B17/52
Filed: 1948-02-04
Abstract: 684,596. Photographic processes and devices. INTERNAIONAL POLAROID CORPORATION. Feb. 4, 1948 [Feb. 19, 1947; Dec. 9, 1947], Nos. 3261/48 and 3262/48. Classes 98 (i) and 98 (ii). The process comprises passing a strip of material into a container of processing liquid through an entrance opening of the container of substantially the same width as the thickness of the material, and drawing the material out of the container through an exit opening of greater width than the thickness of the material, thereby forming on the material a film of the liquid in the container, said material passing along and substantially in contact with the wall portion of the container between the entrance and exit openings, and superposing second strip of material upon the first strip, one of the strips being of exposed photosensitive material, and the second strip being either (a) introduced into the container through a second entrance opening therein when the superposition takes place just before the first strip leaves the exit opening, or (b) superposed upon the first strip just after the latter has left the exit opening. The device comprises the container for the liquid with entrance and exit-openings, one side of both of these being constituted by the same wall portion of the container; and also the container with liquid therein and a strip of material threaded through the entrance and exit openings including also sealing means for confining the liquid to the container when the material is not being moved therethrough but adapted to be rendered inoperative to permit formation of the film of liquid on the material. As shown in Fig. 1 the container 14 comprises a bottom wall 16, front wall 18, rear wall 20, flexible top wall 22 and side walls 24; openings just above the bottom wall 16 receive sheet 12 which is, therefore, in contact with the liquid in the container, and this liquid may be a viscous solution of a reactive ingredient capable of processing a photo-sensitive layer. Another sheet 10 is adapted to be laminated to the sheet 12 by the viscous solution as both sheets are drawn in the direction of the arrow. Either of the sheets 10, 12 may comprise an exposed photo-sensitive material as of the diazo or silver halide type and in the latter case the other sheet may provide a positive of the first developed negative by transfer and reduction of silver halide which has not been affected by the exposing light. The various parts of the container may be made of metal, paper or plastic materials as described in Specification 684,592, and the contained liquid may be viscous and may include all substances, such as developer and silver halide solvent, necessary to effect the transfer operation or the liquid may comprise only a solvent for reactive ingredients carried elsewhere such as in the photo-sensitive layer or the other sheet material. The container may be mounted in a camera which includes, as shown in Fig. 1, a back wall 34 to which is hinged a bottom wall 36, the juncture of the two being a light-sealed opening 38. Figs. 2-8a (not shown), exhibit a variety of shapes and constructions for the container in some of which both of the strips of material pass through the liquid, and show sealing means for the liquid consisting of a springy lip of one end wall adjacent to the opening, which springy lip bears on to the cooperating end wall, or consisting of an actual seal which is arranged to be ruptured by pulling a string provided therein, or by movement of the strips of material. In all of these cases at least one wall of the container is flexible and arranged to collapse inwardly as the liquid in the container gets used up. Fig. 9 (not shown), indicates use of the process and device in a cinematograph type of camera in which after exposure of a negative material, particularly an infra-red sensitive silver halide emulsion coated on a paper base, the positive image may be received on a transparent sheet, which latter may be stripped from the negative to allow viewing of the image by a lamp and lens system provided; the assembly being of special use when it is desired to look through fog or clouds. Figs. 10, 11 show a preferred form of apparatus which embodies a completely different form of container. In these Figures a photo-sensitive sheet 233 from a roll 218 is arranged to pass upwardly with intermittent motion past a lens and shutter system 204 for exposure, and over roll 224 to compression rolls 222 where this sheet 233 meets a sheet 235 from supply 220 for receiving the positive image; and the container 246, with side walls 244 and end walls 264, is open at the bottom so as to permit application of processing liquid to the two sheets 233, 235 in the nip of the compression rolls 222. Processing liquid 239 carried in reservoir 240 is preferably maintained under pressure of an inert gas such as nitrogen and is permitted to enter the container 246 by valve assembly 266, pipe 262 and valve 250, which latter may be operated by solenoid 252. The sheets 233, 235 after receiving processing liquid pass downward; the photo-sensitive sheet 233 is separated at the position of rolls 232 and wound on take-up spool 230, while sheet 235 carrying positive images passes out of the apparatus at the position of a lightseal 236.