Red Moon

The app is free on F-Droid and on GitHub but you can buy it on the Google Play Store to support the developer.

Red Moon is a screen filter app for night time phone use. When the lowest brightness setting of your phone won't do the trick, Red Moon makes your screen even darker. With Red Moon, using your phone in the dark won't hurt your eyes and thanks to it's red filter feature, you will have a healthier sleep.

Features:

• Control the filter with separate color, intensity and dim settings
• Use the default profiles or create your own to quickly choose the right filter settings
• Schedule automatic turn on and off times, so you don't have to worry about turning the filter on at night
• Use the persistent notification to pause or stop the filter without leaving the application you're using
• Control the filter with a widget or a shortcut, right from your homescreen