Figure 1-8.
5.
Color Evaluation.
Influences on color quality such as absorption, reflection, haze,
scattering, interference, dispersion, and fluorescence must be considered
when evaluating color quality.
a. Absorption.
Most color occurs when illumination, falling on the
subject, is not evenly absorbed at all wavelengths.
If the subject did
absorb all wavelengths equally, we would have to illuminate the subject with
colored light to see color. Thus, under normal conditions, the color of the
subject is dependent on its absorption and reflection characteristics in
relation to the various wavelengths present in illumination.
b. Specular and Diffused Light. If the surface of the medium
contacted by the incident light ray is smooth and polished, the
surface reflects the light at the same angle to the surface as the
incident light. The path of the light reflected from the surface
forms an angle exactly equal to the one formed by its path in reaching
the medium. In this case, the angle of incidence is equal to the
angle of reflection, which is a universal characteristic of specular light.
If the surface is rough and irregular, the incident light rays are
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