Hi I've managed to set the gamma value, though not the way it should be done. A solution is to make an /etc/X11/xorg.conf with "Gamma ..." in the monitor section: ----snip---- Section "InputDevice" Identifier "Generic Keyboard" Driver "kbd" Option "XkbRules" "xorg" Option "XkbModel" "pc105" Option "XkbLayout" "de" Option "XkbVariant" "nodeadkeys" EndSection Section "InputDevice" Identifier "Configured Mouse" Driver "mouse" EndSection Section "Device" Identifier "Configured Video Device" EndSection Section "Monitor" Identifier "Configured Monitor" Gamma 1.75 EndSection Section "Screen" Identifier "Default Screen" Monitor "Configured Monitor" EndSection ----snip---- It works, although the value should be set with a KDE/Trinity configuration option instead. I'm sure I had set the gamma value in KDE configuration, most probably in "display". But now, it has disappeared. Seems my installation is screwed. I've tried reinstalling KDE4, but the gamma configuration option didn't appear. Bye, Volker