PURPOSE: To enhance both hardening degree and mechanical strength of a gelatin layer by incorporating an org. hardening agent and the alkali salt of acetylenedicarboxylic acid as a hardening adjuvant in a photographic layer contg. gelatin.

CONSTITUTION: A gelatin-contg. layer incorporates an org. hardening agent, such as 2-oxy-4,6-dichloro-s-triazine in an amt. of 0.01W1mmol par 1g of gelatin, and an alkali salt, such as sodium salt, of acetylenedicarboxylic acid as a hardening adjuvant as an effective amt. by 0.1W2mmol per 1g of dry gelatin, preferably, added after the second ripening of a silver halide emulsion. As a result, the gelatin-contg. photographic material is permitted to reach a saturation hardening level in a short time, and posthardening phenomenon and fogging can be prevented.