xgamma allows X users to query and alter the gamma correction of a monitor via the XFree86 X server video mode extension (XFree86-VidModeExtension).
This client changes the internal values of the gamma correction for the Xserver. Whether or not these values are respected depends on the video drivers.
The gamma values are passed to the Xserver with 3 decimal places of accuracy.
Static Wikipedia 2008 (no images)