A unit of absolute temperature often used in photography to measure the color temperature of a source of light. Abbreviated K, kelvins can be converted to degrees Celsius by subtracting 273. Certain tungsten lamps are designed to burn at specific absolute temperatures (usually 3200 or 3400 K), guaranteeing that compatible photographic films will render the color they illuminate quite accurately.Here are the color temperatures of common light sources: light source color temperature approximatedecamired value overcast sky 6700-7000 K 15 electronic flash 6200-6800 K 16-15 hazy sunlight 5800 K 17 average daylight 5500-6000 K 18-17 morning or afternoon sunlight 5000-5500 K 19 500-watt amateur photoflood lamps 3400 K 29 500-watt studio flood lamps 3200 K 31 100-watt general-service lightbulb 2900K 35Also see color, incandescence, neon, phosphene, photon, stroboscopic, ultraviolet, value, and x-ray.