The present invention relates to a process for dyeing keratin fibres, in particular human keratin fibres such as the hair, in which the said fibres are treated with one or more cosmetic compositions containing, taken together or separately in the said composition(s), the fo llowing ingredients : a) one or more ortho-dipheno l derivatives, b) one or more manganese salts or one or more zinc salts, c) hydrogen peroxide or one or more systems that generate hydrogen peroxide, d) one or more (bi)carbonates or one or more systems that generate (bi)carbonate(s), and e) one or more basifying agents other than the (bi)carbonate(s), and f) one or more salts chosen from titanium salts and scandium salts it being understood that the pH of at least one of the compositions comprising at least one of the ingredients a), b), c), d), e) and/or f) is alkaline, i.e. greater than 7, and that the composition comprising f) the salt(s) chosen from titanium salts and scandium salts is applied to the keratin fibres as the last step of the dyeing process.
