Photographisches Diffusionsübertragungsverfahren

1,145,144. Photographic diffusion transfer processes. INTERNATIONAL POLAROID CORP. May 2, 1966 [May 12, 1965], No. 19241/66. Heading G2C. A photographic diffusion transfer process comprises imagewise exposing a photographic material containing a silver halide emulsion, contacting the emulsion with an aqueous alkaline solution to initiate development of the latent image with a developer containing a dihydroxybenzene benzene group and having at least one unsubstituted carbon atom ortho to one of the hydroxy groups, the developer being oxidized when used in development, and reducing the mobility of the oxidized developer with the emulsion by reacting it with a colour coupler having a methine or methylene group substituted by at least one activating group but being uncharged. The developer is preferably a dye developer and the developer and coupler are preferably incorporated in the emulsion but it is claimed that both dye developer and coupler may be in the processing solution. The photographic material may be a multi-layer one used in the production of multi-colour images as disclosed in Specification 804, 972. The alkaline processing solution may contain an auxiliary developer such as 4'-methyl phenylhydroquinone.