The color of light, expressed in Kelvins (K). The sun is about 5800 Kelvins. This is called a "temperature," because the hotter fire gets, the more it changes from a warm yellow glow to white.The lower the Kelvin rating, such as the common incandescent/tungsten bulb, the warmer, softer and more yellow the light. The higher the K number, the cooler, whiter and bluer the light. See white balance. Approximate TemperatureLight In Degrees ofSource Kelvin (K) Match/Candle 1,700-1,800 Warm/More Incandescent 2,600-3,000 Yellow| Halogen 2,800-3,400 || Fluorescent 3,000-4,300 Daylight| Outdoor sun 5,000-6,000 || Outdoor shade 6,000-7,000 Cool/Whiter/ North sky 10,000+ Bluer LED lights range approximately from 2,600 to 5,200 K.