The present invention relates to i) a composition comprising a) at least 10% by weight of powder may be used and / or of plant (s) indigofère (s), b) at least one oil, c) at least one (bi) carbonate, d) at least one acid； (ii) a process for dyeing keratinous fibers, for example, human, such as the hair, using the said composition； and iii) the use for dyeing keratin fibers of the combination of a), b), c) and d), such as defined above. The composition according to the invention makes it possible to dye keratin fibers, with the results of the colorations that are strong, chromatic, resistant to washing, perspiration, the sebum and to the light and more durable without alteration of the said fibres. In addition, the use of the composition does not give off dust of raw materials ("dust - free »). This composition can be used easily, in complete safety and without risk of staining. In addition, the dye composition and the active agent, are stable on storage. The keratin fibres treated have a very pleasant cosmetic, their integrity is respected.
