BLH calculation



  • Hi, I just love having f.lux on my laptop, it makes working long hours so much better!
    Looking at the rainbow examples, I was wondering is the blue light hazard value calculated? I have read some papers on trichromaticity functions, luminance etc... do you use a normal or a corrected photopic function? and what is the value in "µW/cm2/lux" is that to measure the circadian impact? why use a ratio radiometric/photometric?



  • You can choose "Blue Light Hazard" from the blue action spectrum menu, e.g.,: https://fluxometer.com/rainbow/#!id=iPad Pro/6500K-iPad Pro&action=BlueLightHazard

    IEC62471 specifies that there is no BLH under 500 lux for large sources, so there is just not much to say about computer displays.

    The candela is an SI unit, so even though it's an imperfect measure, everyone is going to use "lux" forever.

    The metric you reference is "actinic power per lux" and gives you a relative measure of how much of the action spectrum is active at a certain intensity level. Many many people have "lux meters", and lights are often specified in terms of lux, so this gives a way to compare two lights at the same lux level.


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