Most Android devices let you adjust the display brightness. But what if your screen is too bright even at its lowest setting? That’s where Screen Filter comes in.
This free app lets you add a filter on top of your screen, effectively making text, backgrounds, and everything else a little (or a lot) dimmer. If you’ve been avoiding reading in bed at night with the lights off because your phone’s screen is blindingly bright, Screen Filter can make a big difference.
The developer says the app can also help prolong battery life, but I haven’t put that claim to the test.
One thing worth noting is that you probably don’t want to set the filter level too far past 40% or you might have trouble seeing the screen at all. Fortunately there’s a fail-safe in case you accidentally slide the bar too far to the left. I tried setting the filter to 17% at one point and I could barely see the screen. But a message popped up saying that if I didn’t accept the new filter level, it would revert momentarily. You won’t see this warning unless you set the filter to a very low level.
When Screen Filter is active you can adjust the brightness by pulling down the notification bar and selecting your filter level. You can toggle the filter by clicking the icon in your app drawer or placing it on your home screen for easy access.
via reddit