Achromatic

Achromatic means without colour. So any surface or object that lacks a strong hue is said to be achromatic. The pure achromatic colours are black, white and all greys but unsaturated and near-neutral colours are sometimes described as achromatic.

About achromatic colours
  • Achromatic, unsaturated colours include browns, tans, pastel tints and darker tones.
  • When mixing paint colours, achromatic colours are produced by mixing pure colours with white, black or greys.
  • Achromatic colours are produced on TV’s and monitors by mixing RGB colours in equal proportions. So the RGB values 125, 125, 125 produce a middle grey.
  • The appearance of achromatic colours seen by an observer is easily modified by adjacent more saturated colours. So next to a bright red couch, a grey wall will appear distinctly greenish – green and red being complementary colours.
References
  • https://en.wikipedia.org/wiki/colour_scheme>