Why my f.lux says Full Brightness is 88% daylight and not 100?

  • No matter what I change in settings, the max is always 88% daylight... what does it mean?

  • It is our estimate of how your screens will affect your body if you look at them long enough.

    If you were to look at a white webpage on these screens for 4 hours before bed, the prediction is that it would adjust your circadian clock by 88% as much as sitting outdoors while the sun is up for the same time. Which is a whole lot.

    It's a complicated calculation based on your screen sizes and brightness levels. But you must have a lot of big screens. :)

  • @herf Thanks!
    I do have some big screens :) I work as video editor with quad monitor setup.
    I was afraid that f.lux somehow dims my original screens brightness to 88% of their potencial, and I needed to know this as I do a lot of color related work.
    I assume that normal daytime mode does not change any aspects of my monitors colors and brightness, right? It only starts to change stuff after suset I hope.

  • Yes, thanks for the question. It doesn't affect the peak brightness at all.

    Our abbreviation of "% as big an effect on your body as daylight" is "% Daylight"...it may be too short. Maybe we should write it as 'circadian effect' instead.

    We are trying to nudge people to think of screens and lights as things that have a big impact on how their body works. Not just the sort of aw shucks, let's make it do a little less, but something we can really measure.

    And so your example is a great one, because someone with a 13" laptop screen just sees a ton less light than your 4-monitor setup, and we're trying to put a number on that, so we can "fix" it.

    Most people would probably think f.lux is only changing their screen (maybe that's all they expect), but our work is mostly on how those screens and lights affect your circadian system.

    So when that screen changes your body and circadian timing (and we can measure or simulate it), we are trying to find a way to talk about that effect, which is complicated. But we're trying to do it anyway. :)

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