Turn On JustVanilla Shaders in Your World

JustVanilla is a shader pack. Minecraft only loads shader packs through a shader loader such as Iris or OptiFine, so the loader has to be running before the pack will show up.

Put the pack where the loader can find it

1. Launch Minecraft using the profile that has Iris or OptiFine installed.

2. From the main menu, open Options → Video Settings → Shader Packs. The button name and position vary a little between loaders, but both have a shader pack screen under video settings.

3. Click the button that opens the shader pack folder. This opens the shaderpacks folder in your game directory.

4. Drop the JustVanilla pack file into that folder. Leave it as a zip file. Do not put it in resourcepacks, because it is not a resource pack.

Select and apply it

1. Go back to the Shader Packs screen. JustVanilla should now appear in the list.

2. Click it, then press Apply or Done.

3. Load into a world during daytime.

To check that it is working, stand near a tree or under an overhang. You should see real-time shadows cast on the ground beneath it.

Your blocks and sky colors should look the same as in plain vanilla. JustVanilla keeps the classic textures and adds lighting on top of them. To switch back to unshaded vanilla at any time, return to the Shader Packs screen and choose the off or none option.