Hair-dyeing preparations

A hair dyeing composition containing as oxidation dye precursors, in a total amount between about 0.2 to about 5% by weight of the total composition, a developer component and a coupler component in amounts such as to give a molar ratio between said developer component and said coupler component in the range between about 0.5:1 to about 2:1, both of said oxidation dye precursors being dispersed in an aqueous-based carrier, said coupler component comprising between about 0.05 and about 10 millimoles per 100 grams of total composition of molecules having the formula:

• ##STR4## wherein R.sup.1 is selected from the group consisting of hydrogen, a C.sub.1 -C.sub.4 alkyl group and a halogen atom;
• R.sup.2 and R.sup.3 independently of one another are selected from the group consisting of hydrogen, C.sub.1 -C.sub.4 alkyl groups and C.sub.2 -C.sub.4 hydroxyalkyl groups or, together with the nitrogen atom, form a morpholine, piperidine, pyrrolidine or piperazine ring;
• and R.sup.4 is selected from the group consisting of hydrogen or a --NR.sup.2 R.sup.3 group;
• and salts thereof.