In what unit is color temperature measured?

Color temperature is measured in Kelvin (K). This measurement quantifies the color characteristics of light sources, indicating how "warm" (more red/yellow) or "cool" (more blue) a type of light appears to the human eye. The Kelvin scale starts at absolute zero and progresses through various temperatures that generate distinct colors.

For instance, a candle flame may have a color temperature around 1,500 K, emitting a warm, yellow-orange light. In contrast, midday sunlight can reach about 5,500 K, giving off a neutral white light. Understanding color temperature is essential in photography, as it affects how colors are rendered in images.

Other units like Celsius and Fahrenheit measure temperature but do not relate to light properties, while Lux is a unit measuring illuminance, which relates to the intensity of light falling on a surface rather than the characteristics of the light source itself.