The invention relates to a method of imparting color onto keratinous
substrates involving contacting said substrate with a composition
comprising: at least one triarylmethane dye molecule chosen from
polymeric triarylmethane dye molecules, copolymeric triarylmethane dye
molecules, oligomeric triarylmethane dye molecules, and mixtures thereof;
at least one film forming agent; and at least one solvent; and
irradiating said substrate with a flash of light.