With gulikoza's hint, I was able to set the gamma higher in DOSBox while running 3dfx emulation; this works in 95 but not for statically linked glide titles (for example, EF2000). I haven't tested this for dynamically linked 3dfx/DOS titles. Attached is the minor patch.

The above is tested in a Windows host, but it should work in Linux and others. The downside is the gamma setting may be retained on exiting DOSBox. In this case, it can be set back to the default via the display setttings, or I've used ATI Tray Tools.

Also, I added another patch to disable (many) dithering functions in the Voodoo1 emulation. This is experimental, but the emulation seems a tad faster and better; experts here will know the importance of dithering in 3dfx games.

Edit: 3dfx gamma patch appears stable; however, the 3dfx dithering patch is not stable and not recommended.