The present invention relates to a method for dyeing keratinous fibers, in particular human keratinous fibers, such as the hair, in which the said fibers are treated starting from one or more cosmetic compositions comprising a) one or more ortho-diphenol(s), b) one or more inorganic titanium salt(s) or alkoxytitanium(s), c) one or more acid(s) and d) optionally one or more chemical oxidizing agent(s), such as hydrogen peroxide or one or more hydrogen peroxide generating system(s).