A process for dyeing keratinous fibers, comprising applying an oxidizing agent and components (a) and (b) to said fibers, wherein:
- component (a) contains a suitable medium for dyeing keratinous fibers and at least one single base dye precursor selected from the group consisting of para-phenylenediamines of formula (I):
- ##STR7## wherein R.sub.1 denotes a halogen atom or a C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy radical and R.sub.2, R.sub.3 and R.sub.4, independently of one another, denote a hydrogen atom or a halogen atom or a C.sub.1 -C.sub.4 alkyl or C.sub.1 -C.sub.4 alkoxy radical, and salts thereof;
- and
- component (b) contains a suitable medium for dyeing keratinous fibers and at least one double base dye precursor selected from the group consisting of N,N'-diphenylalkylenediamines of the formula (II):
- ##STR8## and acid addition salts thereof;
- said components (a) and (b) are applied to said fibers either separately or are mixed immediately prior to use;
- said dye precursors are at concentrations in said components that are sufficient for dyeing said keratinous fibers, are selected such that the difference between the value of the intensity of the color on dyed bleached hair (V.sub.B) and the value of the intensity on dyed permanent-waved bleached hair (V.sub.PB) is 0.+-.0.5 and said values are determined using the Munsell Systems for specifying color;
- the molar ratio of the single base dye precursors to double base dye precursors is between 3 and 10;
- Z.sub.1 and Z.sub.2, which are identical or different, denote hydroxyl or NHR.sub.9 groups, in which R.sub.9 denotes a hydrogen atom or an alkyl radical;
- R.sub.6 and R.sub.7, which are identical or different, denote hydrogen atoms, halogen atoms or (C.sub.1 -C.sub.4) alkyl groups;
- R.sub.8 denotes a hydrogen atom, a (C.sub.1 -C.sub.4) alkyl, hydroxy (C.sub.2 -C.sub.4) alkyl, an aminoalkyl group or an aminoalkyl group in which the amino residue is substituted by a (C.sub.1 -C.sub.4) alkyl group;
- and
- Y denotes a radical selected from the group consisting of the following radicals:
- ##STR9## in which:
- n is an integer between 0 and 8, and
- n' is an integer between 0 and 4;
- and wherein said oxidizing agent is present in an amount effective to convert said precursors to dyestuff.