Photographic products, diffusion transfer photographic process, and compounds used therefor

There is disclosed a diffusion transfer photographic system wherein development of an exposed photosensitive element with an aqueous alkaline processing composition is effected in the presence of a compound represented by the formula wherein X represents the nonmetallic atoms necessary to form a nucleus which completes a 5- or 6-membered heterocyclic moiety on said structure including substituted rings and fused rings; R is H, an alkali metal or a group which is cleavable in a photographic aqueous alkaline processing composition; and R1 is either a group, which has a pKa of from about 7 to 14 which is ionizable to an anion whereby the silver salt of the mercaptan (resulting from cleavage or ionization of -SR) is rendered more soluble in the pH range within which R1 is ionized to an anion than it is below that pH range, or a precursor of such a group.