The physics and perception of color temperature
Color temperature in physics is measured in Kelvin and refers to the color of light emitted by an idealized 'black body' radiator at a given temperature. Counterintuitively, 'warm' light (redder, like candlelight) corresponds to lower Kelvin temperatures (~1800-3000K), while 'cool' light (bluer, like overcast sky) corresponds to higher Kelvin temperatures (~6000-8000K). In design, warm and cool refer not to Kelvin values but to perceptual groupings: warm hues are red, orange, yellow, and hues in the 0-60° and 330-360° range on the color wheel; cool hues are green, blue, violet, and hues in the 100-270° range. There is a transitional zone (yellow-green H:60-100°, red-violet H:270-330°) where temperature reading depends on context and surrounding colors.
