| 摘要 |
The invention relates to a novel method for colouring the hair in two stages. In the first stage, the hair is coloured in the region of the hair roots with an oxidation dye using a chemical oxidation agent and in the second stage, the whole length of the hair, or at least some of the remaining portion, is coloured to the same or a similar shade with a non-oxidative hair dye or an oxidation agent which is activated by atmospheric oxygen or a catalyst. The following are preferably suitable as non-oxidative hair dyes: direct natural dyes, nitroaromatics, or coloration systems which consist of reactive carbonyl compounds or stable diazonium salts combined with amino or hydroxyl compounds, or oxidation dyes, which are activated by atmospheric oxygen in the presence of suitable catalysts, such as enzymes or transition metal salts. |
