Gamma correction resets palette
In Doom, when acquiring the radiation suit or berserk, or when taking damage or gathering items, the colors on the screen are changed by changing the palette. Unlike changing the colormap, these actions affect the entire display (including the status bar, sky, and menus). However, hitting the F11 key, which increments the gamma correction value, will reset to the default palette 0.
This glitch can be abused to immediately grant normal vision after acquiring a berserk power-up, or more rarely to clear the yellow tint from picking up too many items at once, or to clear the red tint from acquiring massive amount of pain, although in both cases the palette will shift down to the next less-tinted color (briefly), thus re-obscuring the view. It may also provide a clear view of the menus while the game is paused.
If used after acquiring the radiation suit, the player may forget they possess it, although the warning that it is wearing out will nonetheless be received, because the screen will still blink between palettes 0 and 13 when the power-up is fading. Additionally, if there is another palette change, from pain or from picking something up, the view will return to palette 13 immediately afterward.