Palette

From ZDoom Wiki

These are the built-in Palettes for each game which ZDoom currently supports. Each color has been numbered for ease-of-use with functions such as CreateTranslation.

Doom

Cyan is not transparent!

You should note that the Doom palette does NOT contain cyan, nor is any color in the palette used for transparency due to the nature in which graphics (save flats) are stored in a WAD. Index 247, which is often pictured as cyan (R:0, G:255, B:255) is a convention used by many editing utilities for ease of editing and to better see the outside border of sprites. Index 247 is in fact black and can be used in Doom graphics, though many editing utilities will, sadly, not let you use it. It was probably used first because index 247 is redundant with index 0 and wasn't actually used in any Doom sprites, though it is used in some in Doom 2 and Final Doom.

Heretic

Hexen

Strife