Twilight For Android Changes Your Screen Brightness By Time Of Day

Twilight is an Android app that automatically adjusts your device's brightness (technically, its colour temperature) over the course of the day, reducing the harsh whites and blues as the day progresses. We've talked about how to avoid eyestrain at the computer, but when you're not staring at a computer screen, you're probably looking at your phone or tablet, and Twilight can help.

Once installed, the app slowly adds a soft red filter over your display as the hours drag on. In the morning, your phone or tablet's screen will be bright white, but the app filters out the blues over time to try and reduce your exposure to the kind of bright, harsh light that keeps you awake at night and prevents you from falling into a deep sleep. The intensity of the red filter adjusts automatically, and is based on the sunset and sunrise times where you live. We tried the app out, and it works as advertised, although it takes a little getting used to at first.

Twilight is a bit like F.lux (another app we love) for Android. It was developed by the same guy behind Sleep As Android, one of your favourite sleep tracking tools. If you want to give it a shot, it's free and available now at Google Play.

Twilight (Free) [Google Play via gHacks]


    Er.. Most phones do this.. using the light sensor.. (the same sensor that is usually used to detect when you put the phone against your head)..

    Seems.. Pointless.

      Er.. No.

      No phones do this - this is colour temp, not brightness.

        Just saw what you mean, fair enough :)

        Last edited 10/04/13 10:16 am

    Why base it on the time of day, which is largely meaningless, instead of the ambient light levels of the environment the phone is in at any given time? Oh wait, phones already do that.

      No they don't. Phones change the brightness only. Download this app and try it. You'll see how different it is.

        You're referring to the red tint, I assume. No thanks, it has no effect on sleep cycles (see my post below) and that level of colour inaccuracy would annoy the shit out of me.

        Last edited 10/04/13 9:08 am

    Wow - the posters above. Did you read the article? It's not about light sensitivity, it's colour temperature. Warmer colours are more appropriate at night ... why am I explaining this? Read above.

      Good question, why are you explaining it? It's evident from the article. It's also bunk. Blue wavelength light only affects the human circadian rhythm when the intensity is over 1000 lux, twice the intensity of the brightest smartphones screens at around 500cd/m^2. The colour temperature of light displayed on your smartphone screen has no effect whatsoever on your body's natural cycle.

      All you succeed in doing with this app is tinting your screen based on time of day instead of ambient light levels, achieving nothing other than giving you a subpar experience in the evening.

      Last edited 10/04/13 9:05 am

        It's not about effecting you circadian rhythm - it's reducing eye strain in low to no light conditions. I use flux on my devices, and if it's a placebo I couldn't care less, as it works for me.

          If it was about reducing eye strain in low light conditions, it would be tied to ambient light levels, not your local day/night cycle, otherwise you'll end up with untinted screens at midday in a pitch black room and tinted screens at night in a brightly lit office. I mentioned in my first post above that using ambient light levels would have made much more sense for addressing strain. The day/night thing combined with altering the composition of the emitted light to reduce blues is intended to try to affect the circadian rhythm, which is affected by light in roughly the 450nm range. Reducing eye strain is usually better served by lowering gamma levels, not by tinting which has an adverse effect on contrast.

          If it works for you, even if it's a placebo, that's what matters. I'm just commenting that the apparent motivation behind it doesn't gel with the available scientific data.

            Do you know of an app for better brightness control? On my phone, with brightness set to the minimum, it's still blindingly bright for reading when there's no other light.

            Twilight would be suitable, but every few minutes it jarringly resets the brightness to what it was without twilight.

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