Colour Temperature

Colour temperature is a characteristic of visible light that is conventionally stated in Kelvin. The Kelvin scale is like the more familiar Fahrenheit or Celsius scales, except 0º on the Kelvin scale is Absolute Zero - the temperature at which there is no heat energy left in an object.

Colloquially, colour temperature is often referred to as warm or cold.

Light globes range from around 2500K to 7000K. Most people prefer warm light for cosy corners of the house while cold light is considered 'brighter' and therefore used in workshops, etc. However, colour temperature is not to be confused with luminous flux (lumens) - the perceived total amount of useful light.

FahrenheitCelsiusKelvinAbsolute Zero-460°-273°0°Water Freezes32°0°273°Room Temperature70°21°294°Water Boils212°100°373°Surface of the Sun9937°5503°5776°