A new set of brightness mods have recently surfaced on XDA that can help extend your day. XDA member mattiadj has released two different fixes for those of you looking to make brightness values work a little bit better for you. He has created two different files that you can test out, both are easily flashed through CWM. The first is called bestScreen and is mattiadj’s original file he created to tweak things out a bit. The second uses the values set for the Galaxy Note.
Mattiadj has a standard file for stock XXBLG1 ROM and one for non-stock XXBLG1 ROM’s. As usual, you should always make a backup before you get to flash happy. We nor mattiadj are responsible for any damages you cause to your device by using any of his files. They are created for use with the Samsung Galaxy S III I9300 and not for any other variant. If you are still on board with giving them a test, head over to mattiadj’s XDA thread for the appropriate file and instructions.
Source: XDA