Sulphide & disulphide dyes for use in dyeing keratin-containing fibres

A method of dyeing keratin-containing fibers (such as wool and hair) comprises treating the fiber with at least one sulfide dye of formula [wherein R1and R2 each independently from each other are a residue of an organic dye; Y1 and Y2 each independently from each other are unsubstituted or substituted, straight-chain or branched, interrupted or uninterrupted -C1-C10alkylene-; -C5-C10cycloalkylene-; C5-C10arylene; or-C5-C10arylene-(C1-C10alkylene)-; Z1and Z2 independently from each other are -C(O)-; -C2-C12alkenylene-; -(CH2CH2-O)1-5-; -C1-C10alkylene(C5-C10arylene)-; -C5-C10arylene-; -C5-C10cycloalkylene-; -C(O)O-; R3,R4 and R5 are each independently from each other hydrogen; or unsubstituted or substituted, straight-chain or branched, monocyclic or polycyclic, interrupted or uninterrupted C1-C14alkyl; C2-C14alkenyl; C6-C10aryl; C6-C10aryl-C1-C10alkyl; or C1-C10alkyl(C5-C10aryl); r,q and n independently from each other are 0 or 1, ifn is 0, Z3is hydrogen; and ifn is 1, Z3is -S-] with the proviso that the method does not comprise treating the fiber with an enzyme of the type protein disulfidisomerase (EC 5.3.4.1). Leather, silk, cellulose, polyamides (eg nylon) and cotton may likewise be dyed. Further, there is disclosed compositions comprising dyes of formula (1) (especially comprising other dyes) and processes for the preparation of dyes of formula (1). Certain dyes of formula (1) are claimed per se. Further compounds of formulae (35)-(38) as defined herein are also claimed per se.