If I change the gamma setting for my monitor using the display control in the KDE control center, the setting only works while that control screen is open. If I close it, the gamma goes back to 1.0. The box to load setting at KDE startup is checked. I tried adding a gamma setting to /etc/X11/xorg.conf, and I can see that the new setting is in effect during KDE startup, but it switches back to 1.0 shortly after the desktop appears.