A new class of photographic stabilizers is prepared and their use in photographic materials is disclosed. These compounds are 1-phenyl-3-pyrazolidinone derivatives corresponding to following general formula: ##STR1## wherein: A represents a group capable of adsorbing at the surface of silver halides;L is a divalent linking group and r is 0 or 1;R1 and R2 each represent hydrogen, lower alkyl or substituted lower alkyl.The photographic materials containing the substances of the invention are preferably DTR mono-sheet elements which after processing can serve as planographic printing plates.