Do you have a FULLBRIGHT problem? Yeah i can tell you how to fix it so follow these steps:

[​WINDOWS VERISON]

1. Press Windows + R

2. Type appdata or %appdata% its just the same

3. Look for a file called "options" and open it

4. Look for gamma. It should say gamma: and a number from 0 to 1.

5. Replace that high number with any number of a great size! (0 is the start) there you have it.

[MAC VERISON]

1. Right-click Finder and click "Go to Folder"

2. Type ~/library/Application Support/minecraft

3. Look for a file called "options.txt" and open it

4. Look for gamma. It should say gamma: and a number from 0 to 1.

5. Replace that high number with any number of a great size! (0 is start)

Now that your finished Restart your Minecraft And Enjoy!!