Installing this resource pack is quick and easy. Follow these steps:
The Fulbright 1122 resource pack is a "Fullbright" (or Full Bright) utility. Unlike traditional resource packs that change textures to look like high-definition stone or medieval wood, Fulbright modifies the internal light levels of the game's textures.
For version 1.12.2 specifically, note the following critical requirements: FullBright - Minecraft Resource Packs