Abstract:
The present invention relates to a process for dyeing or lightening keratin fibres, comprising the step of extemporaneously mixing at the time of use two compositions (A) and (B) and of applying the said mixture to the said fibres; the said mixture comprising at least 25% by weight of fatty substances relative to the total weight of the composition obtained from the mixing of two compositions (A)+(B); with: —(A) representing a composition in direct emulsion form whose content of oil(s) ii) is at least 30% by weight relative to the weight of composition (A), and comprising: i) at least one nonionic surfactant that is solid at room temperature and at atmospheric pressure, with an HLB ranging from 1.5 to 10; ii) at least one basifying agent; Hi) optionally at least one additional surfactant other than the solid nonionic surfactants (i), iv) optionally at least one dye; and—(B) representing a composition comprising at least one chemical oxidizing agent. A subject of the present invention is also a multi-compartment device and a composition (A) in direct emulsion form and the ready-to-use composition resulting from the mixing of compositions (A) and (B). The process according to the invention makes it possible to dye keratin fibres in a powerful, intense and/or homogeneous manner while at the same time being easy to prepare and to apply, since the mixture in the form of an oil-rich emulsion does not run, but remains localized at the point of application. The process of the invention also makes it possible to lighten keratin fibres in a noteworthy manner.