| 摘要 |
Some people want the colour of their hair to change gradually over the course of a few weeks rather than abruptly. To this end, the procedure involves a series of successive dyeings giving an increasingly intense coloration. Oxidation dyes are used, the amount of dye solution being the same for all the dyeings but the amount of oxidising agent, which is limited to the stoichiometric amount for the first dyeing, being gradually increased in the successive dyeings until the desired final hue is obtained, the latter then being maintained by repeating the final treatment as required. |
