Lord Kelvin

Kelvin (K)

Photopedia

15 July 2008 14:05

A Kelvin is a measurement unit of colour temperature devised by the scientist Lord Kelvin during the 19th Century. The Kelvin unit of measurement is used most often by scientists while Celsius and Fahrenheit are more common in everyday life (The zero point of the Kelvin scale is equivalent to -273.16 °C).

Light units such as studio and on-camera flash are designed to emit ‘white light’, which is made up of a mixture of all colour wavelengths. These light sources are described as having a continuous spectrum.

This white light is made up of violet, blue, green, yellow and red light. Different light sources have a mix of these wavelengths in differing propitiations. For instance, tungsten light is stronger at the red / yellow end of the spectrum while studio flash contains more blue than red or yellow.

The lower the temperature the redder the light, the higher the temperature the bluer the light.

Candle 1900 K
Household Bulb 2800 K
Tungsten Studio Light 3200 K
Noon Daylight 5500 K
11000 - 18000 K Blue Sky