Comments on Profile Post by Mighty Burger

Find a file called "options" and open it, it should bring up notepad or some word editor

Find the words "gamma"
for me, it was near the top

Change the number. Normally in the options menu you can only change it from 0.0 to 1.0, but here you can change it as high or as low as you want. For you, I would recommend putting 10.0. That will make everything completely bright, without causing any glitches.

Save and exit, then load up Minecraft. You should notice that when you join a world, everything is completely bright!

A simpler way. -

Launch Minecraft.
Settings/Video Settings.
Brightness/Gamma.
Max it out.

The problem with that is it's limited. You can only go from moody (0.0) to bright (1.0). With this method, you can go as far as you want to, really. I assume he already maxed it out in the settings in-game.

Optifine. -

Optifine doesn't do anything to the limit. Trust me, I use it.

Oh well. -