The issue of metamerism in print production

With print, each medium in the production process from original art to image capture, monitor display, proof, and final presswork has its own unique spectral characteristics. The majority of color reproductions utilize cyan, magenta, yellow, and black inks or colorants. But none of those inks are exact spectral matches to the media originally used to produce the original art. As a result, the inks used to create color reproductions are combined to simulate an artwork, but only under one industry standard light source – referred to as “D50” or “D65”.

During production the integrity of the reproduction of artwork is monitored by making comparisons, for example, original to its copy or proof to presswork. The two colored objects are referred to as a metameric pair if they match under at least one combination of illuminant and observer and not match under at least one combination of illuminant and observer. They must also have different spectral response curves.

See full article at:  Quality In Print: The issue of metamerism in print production.