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Definition: color temperature


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 Temperature
  Light             In Degrees of
  Source             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





From Warm to Cool
Increasingly, light bulb packages show the color temperature as a measure from warm to cool. This is a halogen bulb label.