Color and Spectral Mixings in Printed Surfaces

The present paper discusses the concept of subtractive color mixing widely used in color hardcopy applications and shows that a more realistic concept would be "spectral mixing": the physical description of the coloration of light by printed surfaces comes from the mixing of light components selectively absorbed by inks or dyes during their patch within the printing materials. Some classical reflectance equations for continuous tone and halftone prints are reviewed and considered as spectral mixing laws. The challenge of extending these models to new inkless printing processes based on laser radiation is also addressed.