Hardening gelatin-containing layers

摘要

Gelatin hardeners, suitable for use in hardening gelatin-containing photographic layers, of the formula: CHEM in which: X represents O, S or is absent, each Y independently represents 0, S or a bond, each R1 independently represents an aliphatic group of up to 10 carbon atoms or the two R1 groups together represent the necessary atoms to complete a 5, 6 or 7-membered ring, -NR2R3 contains not more than 12 skeletal atoms and R2 and R3 independently represent hydrogen, a cyclic or acyclic group or R2 and R3 together represent the necessary atoms to complete a heterocyclic ring.