It’s a biological fact that the human eye has adapted to the different light intensities it experiences along the day. During the day, we are comfortable with light sources similar to the sun. At night, however, our eyes become more sensitive to daytime light intensity (like when someone turns on a light while you’re sleeping and you feel like you’re going blind.) It takes a few seconds before they finally adapt to the new light intensity presented to them. Many of us dim the lights at night to ease ourselves into a good night’s rest.  But what about your computer?  If you work in front of a computer for several hours a day, wouldn’t it be nice if the brightness and color temperature adjusted to the comfort of your eyes, automatically?

Enter f.lux, an application which detects your time zone and adjusts the color temperature of your monitor to match the light sources convenient for that time of the day. The f.lux website indicates: “During the day, computer screens look good—they’re designed to look like the sun. But, at 9PM, 10PM, or 3AM, you probably shouldn’t be looking at the sun.” Here is a list of the most common color temperature presets (measured in Kelvin):

  • Tungsten: 2700K
  • Halogen: 3400K
  • Fluorescent: 4200K
  • Daylight: 5000K (Noon Sunlight)
  • Computer Monitor: 6500K

As you can see, the lighting of a computer monitor is much more intense than that of sunlight. When using f.lux, our monitor’s color temperature will begin to gradually adjust to a color temperature closer to Tungsten as the sun begins to set. Many first-time users will often notice their monitors turning into a “yellowish tint” when this change kicks in, but we can confirm that this is a change that your eyes quickly adapt to. After a day or two of use, you will wonder how you ever functioned without it. It’s also good to point out that one is not stuck with f.lux’s default settings. Users have the ability to adjust what the color temperature should be during the day and what it should be at night – I use the Tungsten setting during the day and night, my eyes are never strained!  Additionally, users that do color sensitive work (photo or video editors) can easily disable f.lux during this time and then re-enable it when done working.

In summary, f.lux is an application for Windows, OS X, and Linux, that adjusts the color temperature of your monitor one more suitable for the time of the day. This allows our eyes to adjust to a lighting source that is more suitable for the nighttime, avoiding eye strain and ensuring a good night’s sleep.

f.lux can be downloaded here for free.