3 ms·

I know that people anecdotally report complaints about flicker and it's plausible to me that there could be an effect, but the way this piece is written reminds

I know that people anecdotally report complaints about flicker and it's plausible to me that there could be an effect, but the way this piece is written reminds me distinctly of similar essays about WiFi sickness, MSG, and GMOs. It identifies a "health risk", describes the mechanism in terms that sound very convincing, assigns numbers to its cause and effects, provides a table grading health risks of various products, all without linking to a single scientific study demonstrating that the effect is anything other than nocebo. The closest they come is a image of a table that refers to a few institutions that apparently did a study related to PWM (leaving it an exercise to the reader to find the studies they're supposedly referencing) and a link to a Wikipedia page which links to a Scientific American article which says: > In 1989, my colleagues and I compared fluorescent lighting that flickered 100 times a second with lights that appeared the same but didn’t flicker. We found that office workers were half as likely on average to experience headaches under the non-flickering lights. No similar study has yet been performed for LED lights. But because LED flickering is even more pronounced, with the light dimming by 100% rather than the roughly 35% of fluorescent lamps, there’s a chance that LEDs could be even more likely to cause headaches. I'm willing to entertain the idea that LED flicker is actually problematic, but I wish essays like this would be honest about the degree of confidence we have given the current state of the evidence. This piece instead takes it as a given that there's a problem, to the point where they confidently label devices on a scale of Low to Extremely High health risks.

_3yjt 1y ago
IEEE Recommended Practices for Modulating Current in High-Brightness LEDs for Mitigating Health Risks to Viewers : https://standards.ieee.org/ieee/1789/4479/ https://standards.ieee.org/ieee/1789/4479/ There is nothing anecdote about flickering in LED light causing health risks.
- deleted 1y ago
  [deleted]
- demosthanos 1y ago
  I am not questioning that certain types of flickering are harmful, so that there's an IEEE standard for how to safely use PWM does not contradict what I said. What I'm asking for is for articles like this that cite numbers and provide tables purporting to quantify the degree of harm caused by various devices to point to where they're getting their numbers from or, if they can't do that, stop making up numbers and assigning things to "harm" scales that they invented themselves based on vibes. Either there's a study showing that 246 Hz flickering poses "Extremely High" health risks or there isn't.
  - _3yjt 1y ago
    See my comment on the other reply. > Either there's a study showing that 246 Hz flickering poses "Extremely High" health risks or there isn't. They calculated it using the definition from the standard.
    - demosthanos 1y ago
      Can you please cite the page number where this definition exists? When I search for "extreme" in the standard that the other commenter links to I don't turn anything up, so I'm unclear where that classification is defined.
      - _3yjt 1y ago
        31 and 32 (by the printed page number), in pdf it’s 42
        Kirby64 1y ago
        The article contradicts the IEEE paper. They list the 'Xiaomi 15 Ultra' as having a 'Moderately High' health risk, and cite it as having a 2.16 kHz PWM frequency at 30-75% modulation depth. The IEEE article has recommended practices that state: 8.1.2.3 Example 3: PWM dimming Using Figure 20, the recommended practice for PWM dimming at 100% modulation depth is that the frequency satisfies f > 1.25 kHz. This can also be derived using Recommended Practice 1 and solving 100% = 0.08×fFlicker. This level of flicker could help minimize the visual distractions such as the phantom array effects. Seems like even at 100% mod depth, >1.25 kHz is just fine. Also, the article does not seem to distinguish between modulation at reduced brightness, which the IEEE article calls out specifically as something that is unlikely to cause issues. E.g., movie theaters using film all flicker at 48 Hz and nobody complains about that.
- wasabi991011 1y ago
  Here is a non-paywalled link: https://www.lisungroup.com/wp-content/uploads/2020/02/IEEE-2015-STANDARDS-1789-Standard-Free-Download.pdf https://www.lisungroup.com/wp-content/uploads/2020/02/IEEE-2... Sure, PWM light can cause health risks for some people, in some contexts. But taking research out of context is bad science. Do you genuinely believe the Pixel 7 and 8 Pro have an "extremely high health risk", in the context of what a lay person would understand? Edit: I specify 'lay-person' because clearly this is an introductory blog post (or advertisement for Daylight Computer). If they want to use a more specific definition of health risk, then they better define it.
  - _3yjt 1y ago
    The “very/moderate high” comes from the standard itself, which is quantified within the standard. In the context, it is about the probability of having issues, while the effect (mild to catastrophic) is another axis. Considering that they stick to the “official” wording and seeing the criticism, I am not even sure if they can change to a more “lay-person” friendly and be acceptable to all the critics. The standard also linked to the researches during their discussion. Please read it, instead of just randomly throw out things hoping that they supported your argument.
    - demosthanos 1y ago
      You can't just point people at a 60-page paywalled standard and say "the supporting evidence to my claim is somewhere in here, I pinky promise". You are the one making assertions, it's on you to prove that the standard actually does reflect the text of TFA. I'm not going to read the whole standard because I'm not the one making the argument and I can't be bothered doing the research needed to refute every piece of nonsense science that shows up on the internet. What I can do is point out when someone is making unsourced claims and insist that they provide their sources if they want to be taken seriously. Cite the exact page number and quote that you claim justifies the assertion that 246 Hz PWM carries an "extremely high" health risk. Then we can talk.
      - _3yjt 1y ago
mrob 1y ago
There doesn't need to be a health risk for it to be annoying. I personally dislike PWM and I'll continue to personally dislike it even if it's proven safe. Fortunately it's easy to find non-flickering LED lights.
- demosthanos 1y ago
  If the article said "I find PWM annoying" I wouldn't have commented like I did.

_3yjt 1y ago

IEEE Recommended Practices for Modulating Current in High-Brightness LEDs for Mitigating Health Risks to Viewers : https://standards.ieee.org/ieee/1789/4479/ https://standards.ieee.org/ieee/1789/4479/ There is nothing anecdote about flickering in LED light causing health risks.

deleted 1y ago
[deleted]
demosthanos 1y ago
I am not questioning that certain types of flickering are harmful, so that there's an IEEE standard for how to safely use PWM does not contradict what I said. What I'm asking for is for articles like this that cite numbers and provide tables purporting to quantify the degree of harm caused by various devices to point to where they're getting their numbers from or, if they can't do that, stop making up numbers and assigning things to "harm" scales that they invented themselves based on vibes. Either there's a study showing that 246 Hz flickering poses "Extremely High" health risks or there isn't.
- _3yjt 1y ago
  See my comment on the other reply. > Either there's a study showing that 246 Hz flickering poses "Extremely High" health risks or there isn't. They calculated it using the definition from the standard.
  - demosthanos 1y ago
    Can you please cite the page number where this definition exists? When I search for "extreme" in the standard that the other commenter links to I don't turn anything up, so I'm unclear where that classification is defined.
    - _3yjt 1y ago
      31 and 32 (by the printed page number), in pdf it’s 42
      - Kirby64 1y ago
        The article contradicts the IEEE paper. They list the 'Xiaomi 15 Ultra' as having a 'Moderately High' health risk, and cite it as having a 2.16 kHz PWM frequency at 30-75% modulation depth. The IEEE article has recommended practices that state: 8.1.2.3 Example 3: PWM dimming Using Figure 20, the recommended practice for PWM dimming at 100% modulation depth is that the frequency satisfies f > 1.25 kHz. This can also be derived using Recommended Practice 1 and solving 100% = 0.08×fFlicker. This level of flicker could help minimize the visual distractions such as the phantom array effects. Seems like even at 100% mod depth, >1.25 kHz is just fine. Also, the article does not seem to distinguish between modulation at reduced brightness, which the IEEE article calls out specifically as something that is unlikely to cause issues. E.g., movie theaters using film all flicker at 48 Hz and nobody complains about that.
wasabi991011 1y ago
Here is a non-paywalled link: https://www.lisungroup.com/wp-content/uploads/2020/02/IEEE-2015-STANDARDS-1789-Standard-Free-Download.pdf https://www.lisungroup.com/wp-content/uploads/2020/02/IEEE-2... Sure, PWM light can cause health risks for some people, in some contexts. But taking research out of context is bad science. Do you genuinely believe the Pixel 7 and 8 Pro have an "extremely high health risk", in the context of what a lay person would understand? Edit: I specify 'lay-person' because clearly this is an introductory blog post (or advertisement for Daylight Computer). If they want to use a more specific definition of health risk, then they better define it.
- _3yjt 1y ago
  The “very/moderate high” comes from the standard itself, which is quantified within the standard. In the context, it is about the probability of having issues, while the effect (mild to catastrophic) is another axis. Considering that they stick to the “official” wording and seeing the criticism, I am not even sure if they can change to a more “lay-person” friendly and be acceptable to all the critics. The standard also linked to the researches during their discussion. Please read it, instead of just randomly throw out things hoping that they supported your argument.
  - demosthanos 1y ago
    You can't just point people at a 60-page paywalled standard and say "the supporting evidence to my claim is somewhere in here, I pinky promise". You are the one making assertions, it's on you to prove that the standard actually does reflect the text of TFA. I'm not going to read the whole standard because I'm not the one making the argument and I can't be bothered doing the research needed to refute every piece of nonsense science that shows up on the internet. What I can do is point out when someone is making unsourced claims and insist that they provide their sources if they want to be taken seriously. Cite the exact page number and quote that you claim justifies the assertion that 246 Hz PWM carries an "extremely high" health risk. Then we can talk.
    - _3yjt 1y ago

mrob 1y ago

There doesn't need to be a health risk for it to be annoying. I personally dislike PWM and I'll continue to personally dislike it even if it's proven safe. Fortunately it's easy to find non-flickering LED lights.

demosthanos 1y ago
If the article said "I find PWM annoying" I wouldn't have commented like I did.