The concept of color rendition
(CRI) has become a standard in the lighting industry for evaluating
the quality of light being produced by a fluorescent lamp. Although
the actual measurement of color rendition is a highly complicated
process, the basic concept is that the higher the color rendering
index (CRI) rating of the lamp towards the theoretical index of 100,
the better the quality of the light being produced by the lamp.
There are two basic methods that can be used to
accomplish a high color-rendering index in fluorescent lamps. One
method is accomplished by using a full continuous spectrum through
the blending of various phosphors. The other is by using a mixture
of light in the three "primary" color spectrum areas of blue (450
nm), green (540 nm) and red (611 nm). The proper combination
of light output in these three areas can create a high degree of
color rendering at a specific color temperature.