GB1396968A - Photographic direct positive silver halide material - Google Patents

Abstract

1396968 Photographic direct-positive silver halide material EASTMAN KODAK CO 24 Aug 1972 [24 Aug 1971] 39429/72 Heading G2C A photo-sensitive element comprises a support and at least one direct-positive silver halide emulsion layer having associated therewith a non- diffusible coupler capable of reacting with oxidized aromatic primary amino colour developing agent to produce a diffusible dye, the element containing a 2-substituted aminomethyl -5-alkylhydroquinone or a salt thereof. The hydroquinone accelerates development. The element may contain red-, green- and blue-sensitive silver halide emulsion layers having associated therewith cyan, magenta and yellow couplers respectively. The silver halide emulsion layers may contain these couplers and be separated from one another by alkaline solution-permeable interlayers each containing an oxidized colour developing agent scavenger. The substituted hydroquinone may be present in the silver halide emulsion layer(s) or a layer contiguous thereto, and may have the formula:- wherein R 1 and R 2 are each H, alkyl, substituted alkyl, cycloalkyl, alkenyl, aryl or substituted aryl or together with the N atom to which they are attached, complete a heterocyclic ring; and R3 is optionally substituted alkyl. The diffusible dye may be received by a dye image-receiving element containing a pH- lowering layer of polyacrylic acid (see Example 1). A photographic film unit comprises a photosensitive element as defined above, a dye imagereceiving layer and a rupturable container which contains an alkaline processing composition and which is positioned so that when a compressive force is applied to the container its contents are discharged into contact with the silver halide emulsion layer within the film unit, the film unit containing an aromatic primary amino colour developing agent.