1.If the hair graying is inreversible, hair colorant is the main choice for the masking of hair color change.
在无法逆转头发变灰情况下,着剂是恢复头发主要方法。
2.This article describes the use of organic colorants as the optical recording media, such as polymethine cyanine, phthalocyanine, naphthocquinone and photochromic compounds.