Process for coloring keratin fibers comprises treating the fibers with: (i) one or more synthetic or natural tetracyclic compounds (A) and their mesomeric forms, stereoisomers, acid addition salts or base, or hydrates (ii) one or more metal salts (iii) hydrogen peroxide or one or more system for generating hydrogen peroxide and (iv) one or more bicarbonates. Process for coloring keratin fibers comprises treating the fibers with: (i) one or more synthetic or natural tetracyclic compounds (A) of formula (I) and/or (II) and their mesomeric forms, stereoisomers, acid addition salts or base, or hydrates (ii) one or more metal salts (iii) hydrogen peroxide or one or more system for generating hydrogen peroxide and (iv) one or more bicarbonates. X : HO-C= or O=C R 1>-R 6> : alkyl, alkoxy or acyloxy (all optionally substituted), H or OH and bond with dotted line : conjugated C-C single or double bond. Independent claims are included for: (1) color cosmetic composition comprising: one or more ingredient (i)-(iv) and (2) a device having several compartments comprising 2-5 compartments containing 2-5 compositions in which the ingredients (i)-(iv) are distributed. [Image].
