cooldudz believe the issue for me is some sort of photophobia from screens. If I got obsessed with the whole dithering viewpoint, I probably would have went down some rabbit hole of posts about dithering and ended up testing screens that ultimately still gave me symptoms. People can have different viewpoints on what they think this whole thing is about, that is fine. Ensete thinks it's all about software and OS. I think, for me and my situation, it's mostly about light - its intensity, how it hits my eyes, etc. And then other people can think all these things, including dithering, sit on a pie chart where everything contributes to the problem to varying degrees.
We are getting hung up on specific techniques rather than analyzing what they are actually doing.
An example that we have proof of, thanks to Stillcolor, capture card and microscope footage, and a standard calculation as it relates to MacOS Apple Silicon GPU dither.
The community has detected 4 dither frames per refresh cycle at 60Hz on MacBooks. You would use the following rudimentary calculation to determine its frequency:
60Hz / 4 dither frames = 15Hz
The exact number is somewhere around 15.55Hz or so, but the approximation is accurate enough.
This means that Apple Silicon is introducing a 15Hz flicker.
*Note that higher refresh rates actually have the potential to introduce even more dither frames and thus, counterintuitively, can introduce even lower frequency dither than 60Hz screens.
So ignore dithering as a concept and look at the frequency (calculating the modulation would be more complex and require more exacting tools). Established medical papers identify 15-30Hz as the biggest risk factor for epileptic seizures in people with epilepsy. The key phrase being people with epilepsy.
So I agree with you in that like the ocean example, many people will be unaffected. However, this does establish that this particular Apple Silicon dithering technique has the potential for harm in susceptible persons. It is important because it removes the element of guessing and anecdotes by providing empirical scientific data collected across many devices and backed up by established, peer reviewed medical literature and research.
Are most people going to be affected by this? No. But should there the customer be made aware of this and have an option to disable it? Yes. Someone may be able to tolerate strobe lights at a concert for 2 hours. It doesn’t mean anyone would suggest staring at said strobe light every day for 8 hours at work, right? Tolerance does not necessarily correlate with safety.
This also begs the question: why are people without a history of epilepsy, TBI, migraines, or any other visual or neurological condition being affected negatively by dithering? And what separates dithering on one device from another? These are questions that need more in-depth study.
PWM and dithering are usually the go-to flicker-based techniques to blame because they are the ones we can most easily identify using consumer electronic tools. Not many here own a spectrometer to measure wavelengths of light.
Unfortunately, we lack the proper tools and organization to systematically analyze screens. I will disagree with everyone in this thread and argue that all flicker-based techniques are at best problematic, and at worst harmful, and like a nutrition label, consumers should know what is inside their technology before they buy it. And if an option can be offered to disable it via software or alternate builds offered during ordering, all the better. It is helpful knowing the PS5 dithers before purchasing.