Photographic dye diffusion transfer process

Claim 1

The photographic dye diffusion transfer process for the production of colored images, in which a photographic material comprising at least one light-sensitive silver halide emulsion layer and, associated therewith, a non-diffusible dye-providing compound which in its oxidized form is capable of releasing a diffusible dye in an alkaline medium, is exposed imagewise and developed with a silver halide alkaline developer which in its oxidized form oxidizes the non-diffusible dye-providing compound and the latter is split by the developer alkali as a consequence of this oxidation, releasing a diffusible dye in image distribution, in which the improvement comprises the non-diffusible dye-providing compound is represented by the following formula: in which X represents the residue of a dye precursor which is attached to to the SO 2 group either directly or by way of an intermediate member Z; Z represents an alkylene group with 1 to 6 carbon atoms, arylene or a heterocyclic group which is attached to the residue X either directly or by way of an --O--, --S--, --SO 2 --, --NR-- (R=hydrogen or alkyl), --CO--, --CO--NH-- or --SO 2 --NH--group; n is 0 or 1; Y represents the residue to complete a condensed benzene ring; R 1 represents --OR 2 --, or ##STR12## R 2 represents hydrogen, an alkyl group having from 1 to 22 carbon atoms, or a cycloalkyl or aryl group; the said alkyl, cycloalkyl and aryl groups may in turn be substituted; R 3 represents one of the residues given under the definition for R 2 or an acyl group derived from aliphatic or aromatic carboxylic or sulphonic acids; R 4 represents hydrogen or a substituted or unsubstituted alkyl group having from 1 to 22 carbon atoms; and in which R 1 and/or a substituent on the condensed benzene ring which is completed by Y represents or contains a residue which confers diffusion resistance.