Minecraft wiki entry for Resource_Pack, associated text: Colormaps are 256×256 pixel images which tell the game which color to use in each biome. They are located in assets/minecraft/textures/colormap. The game contains two colormaps, foliage.png which colors plants such as leaves (except birch and spruce) and vines, and grass.png which colors grass and grass blocks. Colormaps can be disabled on individual blocks by removing the tintindex tag from the block model.