Mike Lights, Inc. 

Color Temperature

The British scientist, Lord William  Thompson Kelvin (1824-1907)
devised a scale whereby the
color temperature of a light
source with a continuos spectrum
could be measured. His scale
compares the visual appearance
of light source with the emitted
light of a perfect black body that
has been heated. Most theater
stages use lights with color
temperatures ranging from
2000K to 3000K because they
have longer life. As you can see
from Kelvin´s scale graph, the
outdoor color temperatures
range from 5000K to 30,000K.