Helping People Sleep Through the Power of Light
f.lux automatically calibrates the computer or device display's color temperature to the time of the day. The user also has the option of choosing a color preset or disabling f.lux for an hour and returning the screen to its normal calibration. The software offers five preset color settings on OS X: candle, tungsten, halogen, fluorescent, and daylight. For Microsoft Windows, the halogen, fluorescent, and daylight settings are available—as well as Incandescent, Dim Incandescent, Candle as well as Ember. However the user can choose any color temperature from 1200K to sunlight, in 100K increments, so these presets exist mostly as starting off points for further tweaking to taste. The iOS version uses the same presets as the Mac version.
A "Movie Mode" is available on Windows and OS X that reduces the adjustment for 2.5 hours, which is long enough for viewing most feature films.