Degrees Kelvin is the standard unit of measure for color temperature which is a way to characterize the spectral properties of a light source. Low color temperature implies warmer (redder) light, while high color temperature implies a colder (bluer) light. Presets for a number of different light sources and conditions are provided in degrees Kelvin.
Node Group
To select a preset, choose one from the Presets tab.
Color Temperature
The Color Temperature of the image is determined by the difference of the Destination and Source Kelvin parameters. For instance, if your Source Kelvin is 3200 degrees Kelvin and you adjust the Destination Kelvin to 6500 degrees, your image would turn blue. This is the same as using tungsten indoor film meant to be used with lighting balanced for 3200 degrees Kelvin outside in daylight which is 6500 degrees Kelvin.
Destination Kelvin
Sets the destination color temperature of the image in degrees Kelvin.
Source Kelvin
Sets the source color temperature of the image in degrees Kelvin.
Sets the opacity of the color temperature adjustment.
Preserve Highlights
Preserves the white areas of the image.
Exposure Compensation
Exposure Compensation adds back the brightness loss as a result of the color temperature application.
Kelvin can optionally use a gradient that limits where the node is applied. Grad is the transition area between the colored portion and the original image. Its direction, corners and size can be adjusted. Go to the Grad section of Common Node Controls to see how the Grad controls work.