[art4ur]

The red light doesn't seem to travel as far. It's less likely to wake your partner when you peek at your device in the middle of the night.

[internet_user]

that has to do with two things:

1) our photoreceptors in retina have highest sensitivity to blue

2) blue photons are higher in energy than red (1.5x to 2x, depending on specific frequencies/color temps)