此外，天然染料往往是浑浊的颜色而且它们很快褪色。

Further, natural dyes tended to be muddy in hue and fade quickly.

youdao

历史告诉我们，这是因为紫色染料得自海螺，它在阳光下不会褪色，相反，它会变得更明亮，在日晒雨淋之下尤为鲜艳。

History tells us this was because the purple dye harvested from the sea snail did not fade due to sunlight, but instead became brighter and more intense from weathering.

youdao

即便特工要从水路逃生，地图也不会损坏，因为它是用一种防水的染料印制的，不会褪色。

It was printed with waterproof dyes so the colors wouldn't run if an agent had to make a sudden water-borne escape.

youdao