Patent ID: 8328880

Claim:
A method of coloring dark keratin fibers, possessing a tone level of less than or equal to 6, comprising applying to said dark keratin fibers a dyeing composition comprising, in an appropriate cosmetic medium, at least one fluorescent disulphide entity and simultaneously applying to the dark keratin fibers at least one reducing agent, wherein the at least one fluorescent disulphide entity is selected from the entities of formula (I): A-(X) p —C sat —S—S—C′ sat —(X′) p -A′ (I) the organic and inorganic acid salts, optical isomers and geometrical isomers, and the solvates thereof; wherein: A and A′, which are identical, each represent a radical containing at least one cationic fluorescent chromophore; X and X′, which are identical or different, each represent a saturated or unsaturated, linear or branched C 1 -C 30 hydrocarbon chain which is optionally interrupted and/or optionally terminated at one or two of its ends by at least one divalent group selected from: —N(R)—, —N + (R)(R)—, —O—, —S—, —CO—, and —SO 2 —, wherein radicals R, which are identical or different, are each selected from hydrogen or C 1 -C 4 alkyl, hydroxyalkyl and aminoalkyl radicals; and saturated or unsaturated, fused or non-fused, aromatic or non-aromatic (hetero)cyclic radicals optionally comprising at least one identical or non-identical heteroatom and optionally substituted; p and p′, which are identical or different, are each 0 or 1; and —C sat and C′ sat , which are identical or different, each represent an optionally cyclic, optionally substituted, linear or branched C 1 -C 18 alkylene chains.