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，着色剂是恢复头发颜色法。

This article describes the use of organic colorants as the optical recording media, such as polymethine cyanine, phthalocyanine, naphthocquinone and photochromic compounds.

介绍了用作光学记录介质有机染料,如多甲川菁、酞菁、荼醌以及光变色化合物等。