Monochrome

Function
This makes any image black-and-white. Default values are weighed according to the eye's different sensitivity to Red, Green, and Blue, but you can override the weights. Notice that it will reduce a 3-channel image (RGB) to a 1-channel image (BW), and a 4-channel (RGBA) to a 2-channel image (BWA). If the 3 color channels are identical, it is more efficient to use a Reorder with a value of rrr, since only the red channel would be read in. Monochrome reads all 3 channels in, and therefore has more I/O activity.

Parameters
Type
Defaults
Function
r,g,bWeight
float
.3, .59, .11
The defaults are set according to the eye's sensitivity to color, but you can balance the colors differently if you want to push a certain channel.

Synopsis

image Monochrome( image, 
  float rWeight, 
  float gWeight, 
  float bWeight
);

Script

image = Monochrome( image, rWeight, gWeight, bWeight);

Command Line

shake -monochrome rWeight gWeight bWeight