Metamerism is a complex phenomenon involving physics, biology, and perception. Most confuse metamerism with metameric failure (or have never heard of either term). Here are a few helpful terms:
Metamers:
Apparent colors that match under different light sources
Metamerism:
The matching of apparent colors between objects with different spectral distributions
Metameric Failure:
Colors will match under one light source but not another
Geometric Metameric Failure:
Colors match when viewed from one angle but not another
Field-Size Metameric Failure:
The same colors appear different when viewed as small and large areas
Observer Metameric Failure:
Two spectrally dissimilar lights or surfaces produce a color match for one observer but not a second observer, due to differences in the observers’ physiology.
See Photoshop User Magazine – Dec 2008 or the authors blog
http://www.johnpaulcaponigro.com/wordpress/?p=234
The Photoshop Mag article was titled “The Fine Art of Printing” – Understanding Gloss Differential, Bronzing, and Metamerism. When evaluating both print and printer quality, there are three things to watch for: gloss differential, bronzing and metamerism. they all make a subtle but appreciable difference in print quality. the article explains what they are, how you identify them, and what you can do about them…
If you know of any additional (free) links that help with explanations, leave a comment.