Gamma adjust while Multiplayer

[DasK.Gefährlichebohnen]

Have got the old "gamma adjustment is not working, the game is to dark"

BUT:

Since i play the multiplayer i can not patch my game above 1.18.
So i have no cam_ext.cfg but a cam.cfg. In my cam.cfg is a line for gamma. But no matter what i enter there form 0.99 - 0.01 it wont change something about the gamma. Is there any file i can enter and just fix it? Somewhere must be the file regulating it XD

So is there a way to get the gamma working without newDark?