Google has rolled out a new feature to Google Play Books that should make for easier reading on your smartphone or tablet at night. Called Night Light, the feature filters out blue light from the screen, replacing it with an amber hue.
The Night Light feature adapts based on the time of day and natural sunlight available, gradually adjusting the color temperature of the display as the sun goes down. The point of this change, as Google points out, is to greatly reduce eye strain in the evening hours when many people are reading before bed.
Night Light is completely optional, and Google Play Books will prompt you to check it out after you install the latest update. Otherwise, you can toggle Night Light on or off from the font settings menu at any time within the app.
Source: Google