VRay for SketchUp Manual
The Function of Color Mapping
Color mapping is used to adjust how color is actually displayed for a given
image. When V-Ray determines a color value for a given pixel this value is then
interpreted based on the type of mappings in use. This is very useful for
minimizing the amount of an image which is out of the range of what can be
displayed on a monitor.
Types of Color
Open Color Mapping under Options, V-Ray default is set to Reinhard option.
Reinhard is a blend between Exponential Mapping and Linear Mapping. The
result is linear mapping when the Burn value is 1.0; and when it is 0.0, the
result is Exponential Mapping.
Linear Multiply simply means that the color will not be changed from the
generated value to the displayed value, like The image on the left.
Exponential is using color intensity to control brightness and prevent a wash
out situation, but objects' color will become light, like the image on the
HSV Exponential and Exponential are very similar, but will keep the tune and
intensity of the color, like the image on the bottom left.
Intensity Exponential can maintain the RGB ratio, and will only affect the
color intensity, like the image on the bottom right.
Gamma Correction applied to the color a gamma curve. Dark Multiplier is a
multiplier for the colors before they are gamma corrected. The inverse of the
gamma value is the Bright Multiplies (gamma 2.2 should be 0.4545 in Bright
Multiplier). The image is shown on the bottom left.
Instead of applying a gamma curve to each channel (RGB) independently,
Intensity Gamma is applied to the saturation of the color. The image is shown on
the bottom right.