Sulphonamido:naphthol contg. cleavable photographic reactant gp. - for use in silver halide photography, giving images with improved sensitometric properties

摘要

A sulphonamidonaphthol cpd. of formula (I) in new. In (I) R1 is H, alkyl, aryl, alkoxy or aryloxy (opt. substd.); R2 is as R1 but not H.; Phot. is a photographic reactant gp. and Ball is an organic ballast gp. R1 is pref. H and R2 aryl. (I) is a photographic cpd. which can cleave in basic medium and in presence of an oxidised Ag halide developer to release a diffusible photograph reactant, the latter being pref. a dye (precursor) gp. Apart from being easily prepd. (I) has improved properties c.f. prior art sulphonami donaphthol cpds., for as the ballast gp. is in position 7, the position 2 is free for substituents, which allow adjusting the redox properties of the cpd. and its aptitude to deamidation.