Bulb Base Types
The color temperature of light refers to the temperature to which one would
have to heat a "black body" source to produce light of similar spectral
characteristics. Color Temperature is expressed in degrees Kelvin (K). Low
color temperature implies warmer (more yellow/red) light while high color temperature
implies a colder (more blue) light. Moreover, the "color temperature" of
a lamp refers to how reddish, greenish or bluish the lamp appears. If the lamp
appears reddish, it has a lower color temperature (e.g., 2500K-3000K) and is
considered to be "warm" in appearance. If the lamp appears to be
bluish, it has a higher color temperature (e.g., 4000K-4500K) and is considered
to be "cool" in appearance.
Warm White: 2500° K to 3000° K
Cool White: 4000° K to 4500° K
Day Light: 6200° K to 6800° K
Color Rendering Index
The Color Rendering Index, or CRI, is a term in photometry used to describe
the effect of a light source on how well it renders colors. In essence, the
Color Rendering Index (CRI) is a numerical system that rates the "color
rendering" ability of fluorescent light in comparison with natural daylight.
If a lamp has a low color rendering index of 50, it does not render colors
very well. If, however, the lamp has a color rendering index of 80 – 95,
its ability to render colors is thought to be very good to excellent. A CRI
of 100 is considered natural daylight and is assigned to the sun itself.