Psychtoolbox>Datapixx.{mex*} subfunction

Datapixx(‘SetVideoGreyscaleMode’ [, mode=1]);

Set display to present only one color channel as a grayscale image.
The greyscale “mode” determines which of the color channels are used. mode can
take on one of the following values:
0: Disable greyscale mode, and present normal RGB colors.
1: Present greyscale image defined by red color channel.
2: Present greyscale image defined by green color channel.
3: Present greyscale image defined by blue color channel.

###See also: SetVideoMode