Overview –

f.lux is a root-only app that focuses on reducing the amount of strain your smartphone screen puts on your eyes before bed.

Developer: justgetflux

Price: free (beta)


  • Reduces eye strain.
  • Requires root privileges.

Setup –

While f.lux does not require any specific steps to set up, it is important to note that this app does require root privileges. If your phone is not rooted, this will do very little for you. Grant f.lux access to root when prompted, and then peruse the options f.lux offers.

Impressions –

To be honest there’s very little say about f.lux. It’s a simple application that performs exactly as advertised. As the hour gets later, f.lux “warms” your screen, reducing the amount of blue light your eyes take in. In f.lux’s own words:

[blockquote author=””]f.lux removes the bright blue colors from your phone to help you wind down at night and returns your screen to normal the next day.[/blockquote]

[df-caption title=”Options. That wakeup time. T.T” url=”https://www.androidguys.com/wp-content/uploads/2016/03/Screenshot_20160315-203643.png”]

Essentially, what f.lux does is rebalance your screen’s color levels, slowly lowering the Blue output and increasing the Green and Red, so your display is “warmer” and therefore less strenuous on your eyes. There are a number of options in f.lux’s menus – the ability to change the “warmth” of the display at various times in the day and set your wakeup time, for example.

[row][double_paragraph][df-caption title=”Without f.lux.” url=”https://www.androidguys.com/wp-content/uploads/2016/03/Screenshot_20160315-200824.png”] [/double_paragraph][double_paragraph] [df-caption title=”SIMULATED effect of flux.” url=”https://www.androidguys.com/wp-content/uploads/2016/03/homescreen-flux.png”][/double_paragraph] [/row]

[alert color=”red”]Note that since f.lux’s effects work on a root level, I can’t take screenshots of the effect – they’ll just look like any other screenshot. So in the second above screenshot, I simulated the effect of f.lux by dramatically dropping the Cyan and Blue levels and increasing the Yellow and Red levels of the first screenshot. It’s not perfect, but it gives the general idea.[/alert]

The most important thing with an app that does one thing is that it does that one thing. And it does! The display warms as the day goes on, and I noticed a distinct difference in how much strain was put on my eyes before bed, and especially when waking up. Normally my display stings my eyes like crazy upon first waking, but with f.lux, there wasn’t nearly as much discomfort.

What I like

  • It works!

What I don’t

  • Root only.
  • Warm display looks pretty funky.

Conclusion –

f.lux is an app that does exactly what it tries to do – reduce the amount of strain on your eyes late at night by reducing the amount of blue light your rooted smartphone projects.

Google Play Store –  f.lux (preview)

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