Patent GB-1459611-A (GB)
Title: Diffusion transfer colour photographic silver halide film unit
IPC: G03C7/00
Filed: 1974-06-04
Abstract: 1459611 Photographic colour diffusion transfer silver halide film unit FUJI PHOTO FILM CO Ltd 4 June 1974 [4 June 1973]  24796/74 Headings G2C and G2X A photographic film unit contains ( I ) a lightsensitive element comprising a transparent support bearing at least one light-sensitive silver halide emulsion layer having associated therewith a dye image-forming material which, as a result of development, forms an imagewise distribution of a dye image-forming material capable of diffusing through a processing solution, (2) an image-receiving element comprising a transparent support bearing an imagereceiving layer, (3) a light-intercepting element having the same area as the image-receiving element (4) a pressure-rupturable container containing an alkaline processing solution which is capable of spreading the solution between the emulsion layer and the image-receiving layer upon rupture, and (5) a light-reflecting substance in an amount sufficient to form a white background for the transferred dye images, the light-reflecting substance being positioned between the image-receiving and silver halide emulsion layers during processing; and the image-receiving element (2) and the lightintercepting element (3) being relatively fixed at least at one edge in a parallel face-to-face alignment to form a composite structure having an opening for introducing the light-sensitive element therebetween so that the image-receiving layer faces the light-sensitive emulsion layer of the light-sensitive element, which composite structure is adapted to be passed through pressure-applying means after imagewise exposure of the light-sensitive element through its transparent support and introduction of the'light-sensitive element thereinto through the opening thereof, whereby the light-intercepting element (3), optionally together with the lightreflecting substance (5), is capable of protecting the emulsion layer(s) from unwanted further exposure to external light during development of the film unit outside a camera. Silver halide emulsions which are chemically fogged and hence spontaneously developable containing diffusible couplers and silver halide emulsions containing DIR (development inhibitor-releasing) couplers are disclosed in Example 2. The light-sensitive elements contain sensitizing dyes in the examples. Figs. 9 and 10 show cross-sections of film units of the invention comprising leader paper 5, binding member 7, excess processing composition reservoir 9, light-sensitive element 61, transparent support 51, light-intercepting layer 60, transparent support 70, image-receiving member 74, lightintercepting element 3, processing composition container 4, and curved covering member 83 designed to close the opening on passage of the composite through pressure applying rolls. The pressure plate 101 of the camera is also shown. At least part of the light-reflecting substance may be in (a) a layer permeable to processing composition and which covers the light-intercepting layer or image-receiving layer or (b) the processing composition. The surfaces of the light-sensitive element (1), the image-receiving element (2) and the light-intercepting element (3) undergoing frictional contact may be rendered antistatic and/or treated to reduce friction.