Just like materials, some lights require the definition of spectrums. Measured spectrums range and number of channels can be overridden to reduce their memory size.

See the expert materials section for more details.

When the expert mode is enabled, environment using a skybox of type "RGB Panoramic" have an additional Gamma field. This value defines the gamma correction applied to the image.

By default, when the expert mode is not enabled, a gamma of 2.2 is used for textures of type *.hdr or *.exr, and a gamma of 1 is used for all other textures.