5 ms·

What exactly about emitted light is a problem? Light doesn't carry a memory of how it was generated, so it must be some difference in some measurable property,

by mrob 8y ago

What exactly about emitted light is a problem? Light doesn't carry a memory of how it was generated, so it must be some difference in some measurable property, e.g. brightness/contrast/color spectrum/flicker/polarization, or the way these change at different viewing angles. If you know which attributes are important then you might be able to match them with an emissive display.

ben_w 8y ago
Emissive displays don’t generally match the brightness of their surroundings; even with automatic adjustment, most are physically incapable of being as bright as a newspaper in daylight, and many cannot be as dim as a newspaper lit only by one of those small book-reading lights without being switched off entirely. There’s also the spikey spectrum, which looks the same consciously but I’ve seen claims [1] that is messes with our circadian rhythm. [1] I lack the skill to tell if this is real science or neo-mystic woo.
- TheSpiceIsLife 8y ago
  I found this command that works, so far, on all my Linux laptops, to give much greater control over backlight intensity. sudo su -c "echo 200 >/sys/class/backlight/intel_backlight/brightness" Replace 200 with another number for different brightness. Haven't found a Windows nor MacOS equivalent though. I've used it a fair bit in conjunction with Redshift to get a screen that's reasonable for reading ebooks in low light. I'd buy an e-ink laptop tomorrow if there was one.
- orbital-decay 8y ago
  >Emissive displays don’t generally match the brightness of their surroundings How so? You can set any brightness you want to match the environment. Usage under direct sunlight is one edge case e-paper is clearly better at, and any usage with poor environmental lighting is detrimental to your eyes itself, regardless of technology. I'm really sceptical about the entire "E Ink is better for your eyes" thing until I see some serious studies. People managed to ruin their eyesight centuries before computer screens. There's just too many factors at play here, from genetics to typography.
  - jtc331 8y ago
    It’s not that they don’t auto adjust. It’s that they’re physically incapable of the range of light intensity we encounter in a normal day. For example, full afternoon sunlight is something like 150,000 lux, but normal house lighting is ~200(in a good scenario as high as 500-1000). The same is true on the other end of the scale.
- Avamander 8y ago
  I think most people are forgetting that LED backlights are controlled usually using PWM which flickers, fast, but still flickers. I haven't found any research about how it might affect humans. I suspect it would be better if no-flicker current-controlled LED backlight was used instead of PWM.
  - dbuder 8y ago
    LED backlights are current controlled. LEDs don't like having current through them all the time and that's why they are PWM controlled unless it's a crap consumer product.
  - diffeomorphism 8y ago
    According to notebookcheck only about half the devices they tested use PWM: https://www.notebookcheck.net/Why-Pulse-Width-Modulation-PWM-is-such-a-headache.270240.0.html https://www.notebookcheck.net/Why-Pulse-Width-Modulation-PWM... It seems to be well known that it for low frequency PWM it causes headaches for some people, so I would expect that there is at least some research in that direction. That said, it seems to only be a problem for few people and only for very low frequencies.
bonzini 8y ago
Staring directly at a light source strains the eyes more than watching reflected light.
- mrob 8y ago
  By what mechanism of action? It can't possibly be true in general: e.g. staring at the reflection of the sun in a mirror strains the eyes more than staring at a candle.
  - bonzini 8y ago
    A reflection of the sun on a mirror is a reflection of a very strong light source through a perfectly reflective medium.. A book or an e-ink screen is still ultimately sunlight, but it has scattered (which is reflection too) while passing through the atmosphere many times before reaching what you are looking at.
    - Avamander 8y ago
      Could this be some unknown effect of polarized light vs. non-polarized?
    - enriquto 8y ago
      So it's a question of total light intensity, not of being reflected or "direct" (whatever that means).
      - hestipod 8y ago
        I don't think so myself because I don't have pain in full sunlight reading print or E-Ink which is much brighter "nits" than an LED backlight produces ....but even low settings on an LED backlit computer hurt. There is in my opinion a difference between looking into a light source and looking at things that are visible due to reflected light like E-Ink, paper, the objects around us even if I cannot quantify it with scientific explanation.

by mrob 8y ago

ben_w 8y ago

Emissive displays don’t generally match the brightness of their surroundings; even with automatic adjustment, most are physically incapable of being as bright as a newspaper in daylight, and many cannot be as dim as a newspaper lit only by one of those small book-reading lights without being switched off entirely. There’s also the spikey spectrum, which looks the same consciously but I’ve seen claims [1] that is messes with our circadian rhythm. [1] I lack the skill to tell if this is real science or neo-mystic woo.

TheSpiceIsLife 8y ago
I found this command that works, so far, on all my Linux laptops, to give much greater control over backlight intensity. sudo su -c "echo 200 >/sys/class/backlight/intel_backlight/brightness" Replace 200 with another number for different brightness. Haven't found a Windows nor MacOS equivalent though. I've used it a fair bit in conjunction with Redshift to get a screen that's reasonable for reading ebooks in low light. I'd buy an e-ink laptop tomorrow if there was one.
orbital-decay 8y ago
>Emissive displays don’t generally match the brightness of their surroundings How so? You can set any brightness you want to match the environment. Usage under direct sunlight is one edge case e-paper is clearly better at, and any usage with poor environmental lighting is detrimental to your eyes itself, regardless of technology. I'm really sceptical about the entire "E Ink is better for your eyes" thing until I see some serious studies. People managed to ruin their eyesight centuries before computer screens. There's just too many factors at play here, from genetics to typography.
- jtc331 8y ago
  It’s not that they don’t auto adjust. It’s that they’re physically incapable of the range of light intensity we encounter in a normal day. For example, full afternoon sunlight is something like 150,000 lux, but normal house lighting is ~200(in a good scenario as high as 500-1000). The same is true on the other end of the scale.
Avamander 8y ago
I think most people are forgetting that LED backlights are controlled usually using PWM which flickers, fast, but still flickers. I haven't found any research about how it might affect humans. I suspect it would be better if no-flicker current-controlled LED backlight was used instead of PWM.
- dbuder 8y ago
  LED backlights are current controlled. LEDs don't like having current through them all the time and that's why they are PWM controlled unless it's a crap consumer product.
- diffeomorphism 8y ago
  According to notebookcheck only about half the devices they tested use PWM: https://www.notebookcheck.net/Why-Pulse-Width-Modulation-PWM-is-such-a-headache.270240.0.html https://www.notebookcheck.net/Why-Pulse-Width-Modulation-PWM... It seems to be well known that it for low frequency PWM it causes headaches for some people, so I would expect that there is at least some research in that direction. That said, it seems to only be a problem for few people and only for very low frequencies.

bonzini 8y ago

Staring directly at a light source strains the eyes more than watching reflected light.

mrob 8y ago
By what mechanism of action? It can't possibly be true in general: e.g. staring at the reflection of the sun in a mirror strains the eyes more than staring at a candle.
- bonzini 8y ago
  A reflection of the sun on a mirror is a reflection of a very strong light source through a perfectly reflective medium.. A book or an e-ink screen is still ultimately sunlight, but it has scattered (which is reflection too) while passing through the atmosphere many times before reaching what you are looking at.
  - Avamander 8y ago
    Could this be some unknown effect of polarized light vs. non-polarized?
  - enriquto 8y ago
    So it's a question of total light intensity, not of being reflected or "direct" (whatever that means).
    - hestipod 8y ago
      I don't think so myself because I don't have pain in full sunlight reading print or E-Ink which is much brighter "nits" than an LED backlight produces ....but even low settings on an LED backlit computer hurt. There is in my opinion a difference between looking into a light source and looking at things that are visible due to reflected light like E-Ink, paper, the objects around us even if I cannot quantify it with scientific explanation.