Comfortably reading a physical book at night is one of the hardest tasks e-books aim to reproduce. While many reading apps have found solutions that increase contrast and decrease brightness, readers are still staring at a bright screen, making it difficult to fall asleep afterwards.
This week, Google introduced a new feature for the Google Play Books app for iOS and Android, called Night Light. Like the app F.lux on Windows and OS X, this feature lowers the colour temperature of displays based on the time of day, resulting in a reddish hue that slowly deepens as the sun sets.
The corresponding lack of blue light from your device causes less eye strain when reading at night, making it much easier to fall asleep, as our brains respond strongly to the blue light we get during the day. If you’ve ever used an app that changes your screen’s colour temperature before, especially for reading, you’ll likely already know how useful a feature it is.
[source]Official Android Blog[/source]