Kelvin

Kelvin is the unit of measurement for color temperature, adapted from the absolute temperature scale used in physics. In lighting and photography, color temperature describes the apparent warmth or coolness of a light source by reference to the theoretical color of light emitted by a "black body radiator" (a perfect heat-emitting object) at that temperature. Practically: lower Kelvin values (1800K–3500K) produce warm, amber, and orange light like candles and incandescent bulbs; mid-range values (5000K–6500K) produce neutral white light approximating daylight; higher values (7000K–10000K) produce cool, blue-toned light like open shade or overcast sky.

The specific Kelvin values that matter most for video production: candlelight at approximately 1800K, tungsten/incandescent bulbs at 2800K–3200K, LED "warm white" at 3000K–3500K, the sun at noon at 5500K, electronic flash/strobe at 5500K–6000K, and open shade or overcast conditions at 6500K–8000K. Camera white balance presets (Tungsten, Daylight, Cloudy, Shade) correspond to these Kelvin ranges, allowing the camera to compensate for different lighting conditions and render neutral colors under each. Most professional cameras also allow manual Kelvin entry, giving the operator precise control over the white balance setting.

The practical relevance for B2B video production: when shooting in an office with mixed light sources — daylight from windows, fluorescent overhead lighting, and an LED panel added for fill — each light source has a different Kelvin value, and they don't mix cleanly. The camera can only be set to one white balance. Managing Kelvin means either matching all light sources to the same color temperature (using gels or LED fixtures with adjustable color temperature) or choosing the dominant light source as the white balance reference and accepting that other sources will create color casts to be corrected in post.