I’m a computer person. As a computer person, I’m often using my computer late into the evening, and it’s often one of the last things I look at before I head to bed. Sadly, staring at bright computer screens just before trying to sleep is not the best way to fall asleep fast.

Enter f.lux, a software program designed to tone down the brightness of your computer at night. By changing the color contrast on your computer screen at night, f.lux helps your brain recognize that it is, in fact, nighttime. It does this by toning down the blue light emitted by the screen. This gives everything a slightly yellowish tone, similar to an incandescent lightbulb. The trick is that the blue light is secretly telling your brain it is still time to be awake. By toning that down, you will be more likely to follow a natural circadian rhythm.

The only time I really notice the color difference is when I am using my computer at sunset or sunrise when the color changes. I have f.lux to change the color in 20 seconds, which results in a pretty sudden change. There is an option to make the change a much more gradual 60 minutes. Once the change has been made, though, I rarely think about it. Sometimes I even notice the change and turn it off, only to turn it back on because I realize how glaring the bright white of the screen is.

F.lux is free for Windows, Mac, Linux, and for jailbroken iDevices. Download it now.