XDA member fastmikey1969 shares with us an interesting application for your Android device found on the WWW. Screen Filter will let you set very low brightness parameters to your screen with a "filter". Very useful for web browsing, eBook reading or low-light gaming adding extra time to your battery life for AMOLED displays. Tested on Epic 4G.

Important note: If you accidentally make your screen go black, uninstall the app and then reinstall to reset your bad brightness setting.

apk installer link available for download free.

Originally posted by fastmikey1969

Screen Filter - app for low brightness

I really liked the brightness tweak with the ultra low brightness setting.

There's a Screen Filter app in the market which seems to do the same thing, I haven't seen any posts about it here so I thought I'd share.

You can find more information in the original thread.