gamcal(6D)

NAME
     gamcal - visually check gamma display calibration

SYNOPSIS
     /usr/sbin/gamcal

DESCRIPTION
     gamcal checks to see if the gamma correction value is correct by
     comparing the intensity of full on/full off horizontal lines to a region
     of half-intensity grey.  Normally the gamma of the display should be set
     to 2.4 using the program /usr/sbin/gamma.  When the gamma of the display
     is set correctly, there should be little or no change in brightness in
     each column of rectangles in the window.  In the column on the far left,
     the horizontal lines alternate full intensity and black.  The average
     brightness of the top region should be 50% white.  The solid areas in the
     left column are filled with a constant 50% grey.  If the display is
     properly calibrated, the solid and the striped regions should have the
     same apparent brightness.

SEE ALSO
     /usr/sbin/gamma