Crosslinked sulphonated (meth)acrylamide copolymer

摘要

Triazine derivs. of formula (I) are density enhancers for photographic film compsns. In (I), R is H, alkyl, halogenoalkyl, hydroxyalkyl, alkylamino or alkoxy; and Y is O or S. Direct positive film emulsion comprises fogged Ag halide grains and density enhancer (I), which is added during the fogging process in amts. 2-24mg per mol Ag, such that the optical absorption is increased at least 0.08 relative to that obtd. in the absence of cpd. (I). Pref. cpd. (I) is 1-(2-hydroxypropyl)-4-thionohexahydro-1,3,5 -triazine.