There are apps that filter all colours equally, but it's not nearly as good as reducing the backlight brightness would be. When 0-255 is remapped into 0-127 (or

There are apps that filter all colours equally, but it's not nearly as good as reducing the backlight brightness would be. When 0-255 is remapped into 0-127 (or lower), you're inherently going to start losing the ability to distinguish colours. Unfortunately, you lose contrast a lot faster than you lose brightness via that method, so it's not very useful. I wonder if a physical filter for the screen might be the simplest method.