Process for hardening silver halide containing photographic layers with sulpho- or sulphoalkyl-substituted carbamoyl pyridinium compounds

Claim 1

A process for providing a photographic material comprising at least one silver halide emulsion associated with at least one supported layer containing protein in which the protein-containing layer is contacted with an effective amount of a hardener to harden the layer wherein the improvement comprises the hardener is carbamoylpyridinium compound of the formula ##STR13## in which R 1 and R 2 which are the same or different represent an alkyl group containing 1 to 3 carbon atoms, an aryl group which is unsubstituted or substituted which C 1 to C 2 alkyl or with halogen; or an aralkyl group which is unsubstituted or substituted with C 1 to C 2 alkyl or with halogen; or R 1 and R 2 together represent the groups required to complete a piperidine or morpholine ring which is substituted with C 1 to C 2 alkyl or with halogen, R 3 represents hydrogen, methyl or ethyl, R 4 represents ethylene or a single chemical bond, Me + represents an alkali metal cation and X - represents Cl or Br - .