The PostScript language has long been known for very precise, device independent page descriptions of potentially very complex pages consisting of text, graphics, and images. However, in the past the description of color in PostScript has not done justice to the term device independence since the exact meaning of the colorants in a color space was not explicitly specified, but instead was left to the interpretation of each device receiving the given page description. Device independent color is the ability to describe color in a manner independent of the color forming properties of any particular device. Instead color is described based on the CIE system of color specification. PostScript has been extended to afford his manner of color specification.
Ronald S. Gentile,
"Device-independent color in PostScript", Proc. SPIE 1913, Human Vision, Visual Processing, and Digital Display IV, (8 September 1993); doi: 10.1117/12.152716; https://doi.org/10.1117/12.152716