Gamma is increased in fullscreen mode and completely washes out all the colors. I cannot find any setting to fix this. Windowed --> beautiful. Fullscreen --> disgusting. This applies to the latest version of Minecraft and 1.12.2. I do not see why this game doesn't have a gamma/brightness option to match my desktop colors. And no, this is not something I can fix with my monitor (no gamma adjustments – instead done through Windows DCCW), and other games are fine as I can actually adjust them properly.