A subject-matter of the invention is a process for dyeing keratinous substances, in particular keratinous fibers, comprising the application, to the said keratinous fibers: of at least one composition A comprising at least one non-ionic alkylpolyglucoside surfactant, at least one metal salt and at least one thickening polymer and of at least one composition B comprising one or more ortho-diphenol derivative(s).