“Ever wake up ready to write down the Next Great Idea and get blinded by your computer screen?

“During the day, computer screens look good—they’re designed to look like the sun. But, at 9 pm, 10 pm, or 3 am, you probably shouldn’t be looking at the sun.”

The developers of f.lux are right and their application can make your screens easier look at if you do need to use them in the evening or overnight. Read more about how digital screens can affect our sleep patterns.

Just Get f.lux

f.lux is very simple to install. Just download, open the .zip file if necessary, and drag Flux to your Applications folder. Then, open Flux.

The download page provides thorough instructions for getting started, which I also review below.

Where Am I?

f.lux works best when it knows where you are in the world. That way, it can adjust depending on the timing of sunset.

If you click the Location arrow, you should see a map of your current location. If no map appears after a few seconds, you might have Location Services disabled.

Open System Preferences > Security & Privacy > Privacy, unlock the preference pane with your computer password, and enable Location Services. Then, make sure Flux is checked.

Color Preferences

The main settings in f.lux are your preferred color temperatures for Daytime, Sunset, and Bedtime.

By default, f.lux is set to 6500 Kelvin (K), the temperature of daylight. However, I prefer the slightly warmer color of sunlight at 5500K, as you’ll see above.

Additionally, you can set what time you usually wake up and f.lux will adjust accordingly.

Options & Extras

There are some additional options and cool effects in the f.lux menu on the menubar, some shown above.

For example, if you sleep in on weekends, you might want your Bedtime setting to last longer. Or, if you’re watching a movie, you can disable f.lux for a couple hours so the film’s colors aren’t distorted.

My favorite setting is OS X Dark theme at sunset. In the last few versions of macOS, the dark theme changed just the menubar and Dock backgrounds.

In Mojave, there is a system-wide dark mode, as you might notice in some of the above screenshots. Flux beautifully switches between Light and Dark in morning and evening.

[Update: In more recent macOS versions, Light–Dark switching is offered automatically by the system.]