The composition for dyeing fibers is obtained before use by mixing a first component A1, containing at least one enamine of the formula (I) with a second component A2, containing at least one carbonyl compound. A multi-component kit for dyeing and, later on, decolorizing fibers, and a method for temporarily dyeing hair with the composition for dyeing fibers and later removing the dyed hair color with a decolorizing component B containing a sulfite are also provided. The multi-component kit for dyeing and, later on, decolorizing fibers, separately contains the first component A1, the second component A2 and the decolorizing component B.