Abstract: A process of dyeing hair by preparing and applying to the hair an aqueous reaction medium comprising an aminoethanethiol, a dihydroxybenzene and a ferricyanide or persulfate oxidizing agent, the composition optionally containing a color modifier selected from the group consisting of direct dyes, primary intermediates, couplers and mixtures thereof, and also containing a buffer to maintain the pH in the range from 2 to 11 during the oxidation reaction, and removing the aqueous reaction medium from the hair after the desired color is attained, and compositions and kits for practicing such processes.

Abstract: A process of dyeing hair by preparing and applying to the hair an aqueous reaction medium buffered to a pH of from 7 to 11 with a bicarbonate or a TRIS buffer, a catalytic quantity of a cupric or ferrous salt, a catechol and a persulfate oxidizing agent and removing the composition after the desired color is attained, and compositions and kits for practicing such process. The composition may be formed by simultaneous addition of the catechol and the oxidant to the hair or by addition of the catechol followed by addition of the oxidant.

Abstract: A process of dyeing hair by preparing and applying to the hair an aqueous reaction medium comprising an aminoethanethiol, a dihydroxybenzene and a ferricyanide or persulfate oxidizing agent, the composition optionally containing a color modifier selected from the group consisting of direct dyes, primary intermediates, couplers and mixtures thereof, and also containing a buffer to maintain the pH in the range from 2 to 11 during the oxidation reaction, and removing the aqueous reaction medium from the hair after the desired color is attained, and compositions and kits for practicing such processes.

Abstract: A process of dyeing hair by preparing and applying to the hair an aqueous reaction medium comprising an aminoethanethio substituted dihydroxybenzene and a periodate, iodate, ferricyanide or persulfate oxidizing agent, the composition optionally containing a color modifier selected from the group consisting of direct dyes, primary intermediates, couplers, cysteine, dopa species and mixtures thereof, additionally containing a buffer to maintain the pH in the range from 2 to 11 during the oxidation reaction; and removing the aqueous reaction medium from the hair after formation of the desired color and compositions and kits for practicing such processes. The reaction medium may be formed by simultaneous addition of the dihydroxybenzene and the oxidant to the hair or by addition of the dihydroxybenzene followed by addition of the oxidant.

Abstract: A process of dyeing hair by preparing and applying to the hair an aqueous reaction medium comprising dihydroxybenzothiazine and a periodsate, iodate, ferricyanide or persulfate oxidizing agent, the composition optionally containing a color modifier selected from the group consisting of direct dyes, primary intermediates, couplers, cysteine, dopa species and mixtures thereof, additionally containing a buffer to maintain the pH in the range from 2 to 11 during the oxidation reaction; and removing the aqueous reaction medium from the hair after the desired color is attained and compositions and kits for practicing such processes. The reaction medium may be formed by simultaneous addition of the benzothiazine and the oxidant to the hair or by addition of the benzothiazine followed addition of the oxidant.