Hmm, okay, that helps a lot! A nice approximation, but still not quite with the same level of grit.
As I think about it, I think one thing that is happening (that I don’t think used to happen) is that the lights are making a texture brighter than its default value. Especially for Quake and Quake II, I recall that not being an option (because their software modes needed to run in 256 colors.) Is there a way to keep a light from making a texture brighter than its texel values? Or at least a way to minimize it?
BTW when I added the post process volume, it looked like most of those things you said I needed to switch off were already off. Was a misreading it?
Also, how can I enable a nearest-neighbor filtering so the textures looks pixelated?