Diffusion transfer process - using sulphonamide cpd as dyestuff source,for colour pictures without colour developer

Photographic diffusion transfer process (opt. using a film unit for camera development) uses a recording material with Ag halide emulsion coat(s) contg. a sulphonamide cpd. of formula capable of forming an image dyestuff (in which R is OR3 or NHR4; R3 is H or a hydrolysable gp; R4 is H or alkylf R1 is an organic gp. which makes the cpd. non-diffusing during development in an alkaline developer liquid; R2 is a dyestuff (precursor) gp. n = 1 or 2; n = 2 if R is OR3 or NHR4 with R4=H or 1-7C alkyl). Development is in presence of a Ag halide developer cpd., the oxidised developer cpd. formed oxidising the sulphonamido cpd(s). present and the latter splitting up, forming diffusible dyestuff precursor cpd(s). Colour photographs can be produced without the use of colour developer cpds.