Change the value to something high, like gamma:100.0 or gamma:1000.0 .
Press Win + R , type %appdata%\.minecraft , and hit Enter. Step 3: Find the options.txt file and open it with Notepad. Fullbright 1.17
For more control, such as a toggle key to turn brightness on and off, use a dedicated mod. Change the value to something high, like gamma:100
Simple Fullbright supports Fabric, Forge, and NeoForge, allowing you to toggle the effect instantly with a hotkey. Change the value to something high
Search for the line that says gamma:1.0 (or gamma:0.0 ).