Dirty colour a colour containing three primary colours or any colour with black.

不纯的颜色。它含有黑色或三种原色。

youdao

He transformed the assured grandeur of the likes of Jackson Pollock and Willem de Kooning into something much more irritable, sexual and dirty, and he swapped their rich fields of painted colour for the scored, scatological marks of graffiti.

ECONOMIST: The influence of Abstract Expressionism