Underburn is an App that Changes Brightness Level Based on Screen Content [XDA Spotlight]

Underburn is an adaptive brightness alternative which, instead of changing brightness based on light conditions, changes it based on screen contents.

By  Arol Wright Oct 7, 2017

An automatic brightness feature has been present on nearly every Android device for years now. Before Android 5.0 Lollipop, the auto-brightness feature changed your phone's brightness based on the ambient light sensor readings, but the quick scaling up and down was bothersome. Auto-brightness evolved into adaptive brightness with Android Lollipop, which combines auto-brightness with a manual brightness level set by the user, so the brightness level stays generally around what the user wants it to be.