While many users believe that a "Fullbright" effect in Minecraft 1.12.2 requires Optifine, you can actually achieve total visibility in dark caves and at night using a specialized resource pack or a simple system file edit.

: A widely used pack; ensure you download the "additional files" for versions 1.6 - 1.12 to avoid compatibility issues. Method 3: Forge Mods (For 1.12.2)

  • Some resource packs include specially designed GUI or hotbar overlays (e.g., HUD icons with high contrast) to make items appear bright.
  • Most servers allow Fullbright resource packs because they provide a visual convenience rather than a major gameplay advantage. How to Install for 1.12.2 Find a Compatible Pack: Look for packs like Simple Fullbright Fullbright Vanilla

    the file and relaunch the game. Everything, including deep caves, will now be fully illuminated. Method 2: Resource Packs (Simple Fullbright)

  • Runtime shader injection (no OptiFine):