Storage stable, colour developer concentrate giving true colours - contg. an N,N-disubstd. p-phenylene diamine salt with a phosphoric acid

摘要

New colour developer concentrate comprises an aqs. soln. of a new salt of an N,N-disubstd. p-phenylene diamine and, pyro-or polyphosphoric acid, contg. the equiv. of about 105-115% of orthophosphoric acid. The concentrate is used in developer baths in colour photography, true colours being obtd., and very little (and permissable) colour variation being present even after the concentrate has been stored, eg. for 5 weeks. The salts are very stable and stability is only slightly increased by presence of anti-oxidants such as (bi) sulphites. Max. aq. concn. of salts is 50% ascorbic acid, sulphites and bisulphites; their stability is slightly increased by the presence of anti-oxidants. The max. utilisable concn. of the salts in aqs. soln. is about 50%.