5 Optical brightener/U.V. interactions are not by any means the only contributor to the
effects of metamerism. Other contributors include various components of ink and toner
pigments, gloss levels, substrate surface smoothness, etc. These and many other variables can
all cause an object or a print to interact in different ways with the spectral inconsistencies of
artificial light sources. Unbalanced and irregular combinations of light (color) are reflected back
to the viewer when inconsistent combinations of wavelengths from artificial light sources meet
objects with different light absorptive/reflective properties. Color stability between subjects
can only be achieved when viewed under a spectrally balanced and stable illuminant and within
a controlled viewing environment.