A process for removing stain in a photographic material is described which process comprises incorporation of at least one compound of formula (I) wherein X is O or NH; n is 1 or 2, p is 0, 1 or 2, M is hydrogen, an alkali metal atom, ammonium or a cation formed from an amine; each R1, independently, is an amimoacid residue from which a hydrogen atom on the amino group has been removed; each R2, independendy, is hydrogen, C1-C8alkyl, C1-C8alkoxy, halogen, cyano, COOR, wherein R is hydrogen or C1-C3alky1, CONH—R in which R has its previous significance, SO2NH—R in which R has its previous significance, NH—COR in which R has its previous significance, or SO3M, wherein M has its previous significance, or, if n is 1, R2 can also be CO—R3 in which R3 is C1-C3alkyl or phenyl, in that photographic material.