ContrastRGB

Function
The ContrastRGB function applies a contrast curve on each channel individually, so you can tune the channels separately. This differs from the ContrastLum function in that it only changes the pixel value according to its own channel. For a good example of how the functions differ, plug a ColorWheel into both a ContrastLum and ContrastRGB. Notice that the ContrastLum is weighed away from the green values. This also means the ContrastRGB runs the risk of shifting the hue as you adjust your channels.

Parameters
Type
Defaults
Function
Value
float
 1,1,1,1 The contrast value. A higher value means it pushes your RGB values towards 0 and 1. A low value means low contrast. A value of 0 means no change.
Center
float
 .5, .5, .5, .5 The center of the contrast curve. A lower value will make that channel brighter. A higher value will make the image darker. Generally, these values are between 0 and 1.
SoftClip
float
 0,0,0,0 The roll-off value to give a smooth interpolation. A value of 0 means no roll-off.


Synopsis

image ContrastRGB( image, 
  float rValue, 
  float gValue, 
  float bValue, 
  float aValue, 
  float rCenter, 
  float gCenter, 
  float bCenter, 
  float aCenter, 
  float rSoftClip, 
  float gSoftClip, 
  float bSoftClip, 
  float aSoftClip 
);


Script

image = ContrastRGB(image, 
  rValue, 
  gValue, 
  bValue, 
  aValue, 
  rCenter, 
  gCenter, 
  bCenter, 
  aCenter, 
  rSoftClip, 
  gSoftClip, 
  bSoftClip, 
  aSoftClip 
);


Command Line

shake -contrastrgb rValue gValue etc...


Example

shake lisa.iff -contrastr 1.5 1.2 1 1


See Also
ContrastLum, Gamma, Add, Mult,