Because it only changes brightness textures, it rarely causes lag or FPS drops, making it ideal for low-end PCs. Installation Guide for 1.12.2 Download a 1.12.2 compatible Fullbright pack (often titled FullBright3.zip or similar for older versions) from sites like CurseForge Locate Resource Pack Folder: Open Minecraft 1.12.2, go to Resource Packs Open Resource Pack Folder Drag and drop the downloaded file into this folder.
While generally safe on most servers, some competitive servers may consider this an unfair advantage. Always check server rules. Alternatives: If a resource pack does not work, users can edit the options.txt file in their .minecraft folder and set or higher, though a resource pack is safer. Disclaimer: Some 1.12.2 packs may require to properly load the changed lightmaps. FullBright - Minecraft Resource Packs fullbright 1.12.2 resource pack
In the Minecraft menu, select the Fullbright pack to move it to the "Selected" side and click "Done". Optional (OptiFine): While some packs work without it, using OptiFine 1.12.2 Because it only changes brightness textures, it rarely