Process of hardening a silver halide photographic material with a 1-carbamoyloxypyridinium salt

Claim 1

A process for providing a hardened layer in a photographic material containing a light sensitive silver halide emulsion layer and at least one layer containing a binder selected from the group consisting of gelatin and homopolymers and copolymers which contain carboxyl groups coated on a support wherein the improvement comprises applying to the binder-containing layer a hardening amount of a 1-carbamoyloxypyridinium salt of the formula ##STR82## in which R 1 represents a lower alkyl or aryl group, R 2 represents a lower alkyl group or a group ##STR83##in which R 6 represents hydrogen, or a lower alkyl or aryl group, R 7 represents a lower alkyl group and R 8 represents a lower alkyl group; or R 1 and R 2 together represent the atoms required to complete a heterocyclic ring selected from the group consisting of pyrrolidine, morpholine-, piperidine-, perhydroazepine-, 1,2,3,4-tetrahydroquinoline- or imidazolidine-2-one ring, or R 1 and R 2 together represent the atoms required to complete a piperazine ring in which the nitrogen that completes said piperazine ring is a member of the carbamoyl group of a second carbamoyloxypyridinium group, R 3 represents hydrogen or halogen, or a lower alkyl, lower oxyalkyl, cyano, CONH 2 or ##STR84##R 4 represents hydrogen or a lower alkyl group, R 5 represents hydrogen or a lower alkyl group and represents an anion.