Although color is frequently used in computer graphics and presentation material such as slides and transparencies, it is still expensive to provide color prints. In many cases, such as quick proof prints, black & white would be far less expensive, and yet adequate, if colors were properly encoded as identifiable patterns. This paper describes methods for encoding colors as textures, preserving the ordering of lightness while generating recognizable patterns for colors.
Paul G. Roetling,
"Pseudo-Gray Techniques For The Black And White Display Of Color Images", Proc. SPIE 0310, Image Quality, (28 December 1981); doi: 10.1117/12.932860; https://doi.org/10.1117/12.932860