Method of stabilizing organic substrate materials against light

A method of stabilizing a photographically useful organic substrate material selected from the group consisting of an anthraquinone, a quinoneimine, an azo, an azomethine, a methine, a polymethine, an indamine, an indophenol, a carbonium, an indigoid or a formazane dye and a fluorescent whitening agent against the action of light having an absorption peak between about 300 nm and about 800 nm in wavelength by making coexistant with said substrate material in an amount sufficient to stabilize said substrate material to light at least one compound represented by the following general formula (I):

• ##STR16## wherein M represents a metal atom selected from the group consisting of Cu, Co, Ni, Pd and Pt atoms;
• R.sub.1, R.sub.2, R.sub.3 and R.sub.4 may be the same or different and represent a hydrogen atom, a cyano group, a halogen atom, an alkyl group, an aryl group, a cycloalkyl group or a heterocyclic group which may be substituted or unsubstituted and which may be attached to the carbon atom in the benzene ring directly or through a divalent connecting group, or each of R.sub.1 and R.sub.2, R.sub.2 and R.sub.3, or R.sub.3, and R.sub.4 may combine to form the atomic group necessary to complete a 6-membered ring and R.sub.5 represents a hydrogen atom or a methyl group.