Yes, there is, but it doesn't give me optimal results because then I don't use the screen's full capabilities. It's always best to set gamma correctly first. It's highly unlikely that the brighness is too high, as it works great with the current setting under Windows.
So, I definitely don't want to adjust those settings, also because then it won't be correct in Windows any more. I'm developing cross-platform graphics software so I don't want to change it every few hours. I just hoped I could configure the graphics card's gamma and let the O.S. make the switch automatically.
I found out some people have gamma control in XF86Config-4 but this file is generated by my ATI driver config and it never asks for gamma. There's also something called xgamma but I'm not sure what to do with it.
Thanks for any ideas!