Welcome to f.lux v4

This new version of f.lux adapts to your schedule with a super-strong “bedtime mode” that ramps up when your body needs less blue light, and it has tons of new features and better performance too.

There’s one important thing you have to do to make this work. Go set your wake time in the f.lux preferences:

Setting your wake time is important, so f.lux can calculate when to remove blue light a while before bed. (And even the people who don’t sleep very much need more darkness at night.)

Eyestrain vs. Sleep

f.lux is designed to remove a large majority of the light that messes up your sleep. While you can use a gentler setting to relieve eyestrain, it might not affect your sleep as much as you expect–they’re two different things. To explain the difference, we’re bringing numbers about how light affects your body right into the app, so you can pick the right settings for you.

New in this version (v4, 2017)

We made big performance improvements in this version, so for games especially, this new version is a huge improvement.

Here’s how f.lux v4 looks. There’s one big slider, and you can adjust it whenever you want to change it. f.lux will remember what you choose during the day, in the early evening, and at night:

Here’s a list of new features:

  • Presets to help adjust your settings
  • Bedtime mode: a warmer mode gets you ready for sleep
  • Disable by app: disable f.lux automatically for certain apps like Photoshop
  • Disable for fullscreen apps: play movies without f.lux (this even works on one screen at a time)
  • Predictions of how light affects your body
  • Backwards alarm clock: reminders not to stay up too late
  • Color filters for eyestrain and other uses
  • Wider range of color settings
  • New hotkeys to adjust color (alt+shift+PgUp and alt+shift+PgDn)

Changes and improvements:

  • Better performance with games (no stutter)
  • Easier ways to find your location
  • Resolution-independent interface, for high DPI displays
  • DisplayLink (USB adapter) works in a lot more cases

Smart Lighting:

  • Hue integration now supports more light types and uses a more advanced schedule
  • LAN API with support for telling other devices when f.lux changes

And if you preferred the old f.lux settings, you can restore them in just one click (look for “Classic f.lux” in the menu).


Old new stuff (2013)

  1. f.lux can go warmer than 3400K now, down to 2700K. Or even 1200K if you really want it to.
  2. Support for color profiles from a hardware calibrator
  3. Movie mode. This setting warms up your display, but it preserves shadow detail, skintones, and sky colors better than f.lux’s typical colors. It lasts 2½ hours, which lets you watch most feature films
  4. Disable until morning, for late-night crunch mode
  5. A new “darkroom” mode, which inverts colors and gets very red
  6. A map to help you find your location
  7. Hotkeys to dim your display (Alt-PgDn, Alt-PgUp) late at night, so desktop users can dim too
  8. A hotkey to disable/enable f.lux quickly: Alt-End
  9. If you have a laptop, f.lux gets warmer when your backlight dims, like an incandescent lamp
  10. A simple schedule for Philips Hue, so you can f.lux your house

Some more fixes

  1. Safe mode for playing video games without hiccups
  2. Bugs fixed with Intel chipsets
  3. Smoother animations and fading
  4. Better support for Windows 7 & 8

Thanks for using f.lux, and if you need help with the new features, please join us on our support page here: http://justgetflux.com/faq.html.

Copyright f.lux Software LLC 2008-2017