What Does the Term Kelvin Mean When Talking About Photography?

When talking about photography the term ‘kelvin’ refers to the unit of measurement of color temperature. Every source of light emits light at a specific color temperature which can be measured in degrees kelvin or ‘K’. The color temperature of a light source varies from red to blue: Red or ‘warm’ colours are created at low color temperature values, for example a candle which is roughly 1500K. Blue or ‘cold’ colours are created at high color temperature values, for example a camera flash unit is roughly 5000K. Adjusting the white balance in a cameras settings changes the way the camera processes an image to compensate for the different color temperatures emitted by various light sources.

Lots of cold color temperature values in this scene!
Photo: Dan Carr