Why is it so bright on your Minecraft worlds?

Hallo Leudis,

Sometimes when I look at certain Minecraft Youtubers (e.g. Dream) at night or in a cave always so bright.

How did they do it?

You can change this in the graphics settings

There are different options, perhaps Nightvision or with a special client (for example, Full breaks with BAC). But most likely it is that gamma has been raised.
Simply Win + R → enter% appdata% in the search window → open .minecraft folder → open options.txt file → press ctrl and f and search for gamma → set gamma to 8.0 instead of 1.0.

Full Bright or gamma in the options.txt (in the .minecraft folder) to 10

Better 10 than 8.0