Hey, I'm running Kubuntu 10.04 and recently reinstalled tremulous 1.1 and 1.2 and when I use the command /r_gamma nothing changes.
Did you try /set r_gamma
Did you try to change the brightness in the menu of the graphical interface?
If all else fails, you may change gamma of X by using the xgamma-command, which currently I myself do with a script that invokes Tremulous.
yeah I have...I might just be stuck with using xgamma
Rather than using xgamma, I'd recommend using /r_overbrightbits and turning it up until the game looks right.
Are you sure you have all of your latest drivers installed?