xcalib is a program that allows you to use ICC profiles (to load its
'vcgt'-tag) for display calibration on X11-Servers with XVidModeExtension
supported (like X.org or XFree86 4.x.x). It can't create the profiles
so you need to acquire them elsewhere (e.g. from some commercial
program or from your display vendor).

xcalib is a postcardware. So if you like this program, send a picture postcard 
from your country/area to:
  
  Stefan Doehla
  Steinselb 7
  95100 Selb
  GERMANY

WWW: http://xcalib.sourceforge.net/