Anyone in London, UK with f.luxometer?

  • Hi everyone,

    I got an ASUS laptop with OLED screen and they claim it produces '70% less blue light'. I would love to measure the screen with f.luxometer quickly. I'd be happy to travel to you and to post my findings here for all to benefit.

    Scroll down slighty:

    Happy new year,

  • Yes would love to see the data - usually it only changes by around 20% for OLED.

    Here's what it usually means:

    OLED moves the blue primary to >460nm from 450nm or so for LED. So there are two methods (both kind of wrong) for figuring out "how much":

    1. Wavelength range cutoffs: People pick a range of wavelengths they deem problematic, and measure the percentage in that range. Usually with numbers like 70% this is what happened. There are no standards for cutoffs like these because there are no opsins/structures that have a big reaction to one wavelength and no reaction to one right next to it. So I would not put much stock in these, no matter who says them.

    2. A few players have adopted the IEC62471 "blue light hazard" as the thing to minimize, which sounds better (at least it's based in retinal harm studies). But the scientific consensus here is that there IS no blue light hazard below about 10,000 cd/m2, about 20x brighter than a display. If there were such a problem, then the blue sky would make you lose your vision. Here is where you will see smaller 10-20% changes, and the trouble here is that this is kind of small. If there IS a problem you need to change it by more than that.

    Neither of these methods deals with circadian or alerting light (which is the main idea with f.lux). But it's important to say that research is ongoing to see if there are effects on the retina (say late at night) or due to extended use into the night.

  • Here is an example for what happens when using "blue light hazard" metrics with LED to OLED.

    Here's an iPad Pro:!id=iPad Pro/6500K-iPad Pro&action=BlueLightHazard
    0.0930 µW/cm2/lux

    An iPhone X:!id=iPhone X/6500K-iPhone X&action=BlueLightHazard
    0.0808 µW/cm2/lux

    The second screen would be "safe" according to one industry standard, but the change is only 13% less "hazard" light with the second spectrum.

    But because these things happen over orders of magnitude - if there is a problem, you want 90% less harmful light or 99% less, not 13%.

    Dimming your screen can do this kind of thing (and f.lux can do part of it too).

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