PURPOSE: To photochemically stabilize a polyamide fiber material and prevent waste water from being contaminated with copper-containing impurities, by treating a dyed polyamide fiber material with an aqueous foamed composition which contains a specific non-dyeing copper complex.

CONSTITUTION: This process for the photochemical stabilization of a dyed polyamide fibre material comprises treating the dyed material with a foamed aqueous composition which contains at least a non-dyeing copper complex of bisazomethines, acylhydrazones, semicarbazones or thiosemicarbazones of aromatic aldehydes or ketones or oximes. The non-dyeing copper complex is preferably a copper complex of the formula [R is H, an alkyl, an aryl or the like; Q is an alkyl, a cycloalkylene, an aryl or the like; (n) is 0, 1, 2 or 3].