Patent GB-732420-A (GB)
Title: Improvements in or relating to photographic product and process
IPC: B65D5/60
Filed: 1953-07-03
Abstract: 732,420. Photographic product and process. INTERNATIONAL POLAROID CORPORATION. July 3, 1953 [July 17, 1952], No. 18480/53. Class 98 (2). A photo-sensitive or photo-sensitizing composition is contained within a cavity in a deformable container which has adjacent sections defining a rupturable mouth so that application of mechanical stress to the container will cause separation of the mouth defining sections and permit ejection of the composition. The container may be constructed generally as described in Specification 684,592 and the composition may comprise a silver salt, a chromate, a ferric salt, a diazonium compound, or a silver halide sensitizing or hypersensitizing agent. The container may form part of an assemblage including one or more sheets upon which the contained composition may be spread to form a coating of photo-sensitive or photo-sensitizing substance and a second container with processing composition may be present and operated similarly after photoexposure so that processing may be effected, means being provided to permit successive applications of stress to the two containers. As shown, Figs. 1, 2, container 24 with mouth 32 carrying phoso-sensitive composition and a shorter container 26 with mouth 34 carrying processing composition are placed between a pair of sheets 20, 22 one or both of which may be transparent, and incompressible elements 40 are provided at the ends of container 26. On drawing the assembly in the direction of the arrow, Fig. 2, between the two pairs 36, 36 and 38, 38 of compression rollers the longer rollers 36 are prevented from stressing container 26 by the incompressible elements 40 but they do stress container 24 to release its sensitizing composition through mouth 32 and spread this over area 28 between sheets 20, 22. Continued drawing of the assembly after exposure of area 28 permits shorter rollers 38, unhindered by elements 40, to stress container 26 and spread the processing composition over the same area. Fig. 3 shows a modification including an additional layer 44 which may be a silver halide emulsion or a material suitable for dichromate sensitization, in which cases containers 24, 26 may contain a silver halide sensitizing dye and silver halide processing composition, or else a dichromate solution and a water-soluble dye for coloration of material differentially hardened by the dichromate process; and innumerable alternatives of similar nature among the known ranges of sensitizing and processing materials are referred to; the general purpose as regards photo-sensitization being the maintenance of the photo-sensitizing composition or some ingredient of it sealed in the container until the time for exposure, whereby deterioration on storage of photo-sensitive material already in layer form is avoided. In a preferred form of the invention positives may be produced directly by the migratory transfer process, for example using the procedure of Specification 703,231. For threecolour work three containers may be provided, whereby a red-sensitive emulsion with a cyan coupler may be spread and exposed through a red filter, followed by a green sensitive-magenta coupler emulsion on the same area for exposure through a green filter, and then a yellow coupler emulsion for blue exposure, to provide a multilayer assembly for conventional subtractive processing.