Shake - DelogC

DelogC

Function

This function performs a Log to Linear color correction, usually converting a Cineon scan into linear color space. You can adjust the black and white points, gamma, and do color adjustments. The really swank thing is that we also have controls to provide a smooth rolloff around the black and white points. All values are in between 0 to 1023. Keep in mind for the Offsets that 90 points equals one f-stop.

Parameters	Type	Defaults	Function
Offset	float	0	These values offset the individual color channels.
black, white	float	95, 685	These set the black and white cutoff points. The default values are 95 and 685.
nGamma	float	.6	The film negative gamma. The default is .6, as per the standard Kodak specification. Generally, this number is not touched, unless you use a non-standard film stock.
dGamma	float	1	The display gamma to compensate for the monitor's lookup table. By default, this number is 1.
softClip	float	0	The rolloff values on the white point. Default is 0, which gives a Linear break. By increasing this value, you smooth the curve out.

Synopsis

image DelogC( image, 
  float rOffset, 
  float gOffset,
  float bOffset,
  float black,
  float white,
  float nGamma,
  float dGamma,
  float softClip
);

Script

image = DelogC( image, 
        rOffset, gOffset, bOffset, 
        black, white, nGamma, dGamma          
        softClip
);

Command Line

shake -delogc redOffset greenOffset etc...

Example of the SoftClip
Create a horizontal 2-byte Ramp, add a DelogC, and then attach a PlotScanline. Push the SoftClip values up (say, around 20 or 30) to see the rolloff.

See Also
LogC