Mark V uses contrast for brightness, Fitz uses gamma for brightness.
In the Release #14 download zip, there are 2 exes, one named something to the effect of "hardware_gamma" and that one uses classic FitzQuake hardware gamma.
#14 with the hardware gamma version available
The future ones will have that available in the download.
(But what I have been trying to do, is factor out settings. gamma brightens, but bleaches out the textures.
The contrast option can be accessed in the hardware gamma version via typing contrast in the console.
But I don't want to add an extra slider bar for contrast
... At least I'd prefer not too ...]