reaganry pro tip. if you turn the color all the way down.. no FRC/ color temporal dithering.
I'd be fine with that personally as nothing I do requires "vibrant" colors etc...I'd be fine with black and white for 90% of things honestly...but how? I just want to shut off dithering to see if its the problem and to continue to be able avoid it if it is. I don't care HOW we do it.
Seagull Monitors may have their own dithering function, particularly TN monitors which generally can't do 8-bit natively, so dither up from 6bit. Might be worth considering that there are different algorithms for dithering, I suspect I am more tolerant of some than others.
This confuses me further since the most safe displays people talk about are CCFL/TN. I have one safe 2006 Era CCFL/TN laptop panel...and one 2012 IPS/LED on an iPad 2...but every other panel of any type I've been able to try in the last year has caused strain. Every laptop panel I tried in various 2014-2015 Thinkpad's were IPS and 6bit natively, although were called "6+2" in the specs meaning 6 actual and 2 FRC as I understood it. I can't find a single panel of any type that makes those laptops usable and none of the brand new laptops I have tried in various shops don't strain me.
Seagull It sounds at once logical from a detached point of view...but also so hard to believe because it's hard to accept that things in the ms range could really take something from unnoticable to eye straining. It feels like when people argue over fps etc and is reaching. But like everything else we deal with unless we could objectively test it we can't know. It feels like display tech is out to kill us sometimes. Adding more and more noxious stuff for the sake of pretty.
It is an over-simplification, but it might help to consider that a 30ms response time would equate to about 33frames per second (or Hz). If that monitor has a nominal refresh rate of 60fps (or Hz), then it may not respond fast enough to show any dithering.
Its kind of similar to the argument where ccfl pwm is more tolerable than led pwm because the rate of change of colour is slower and not instant.
Seagull I was thinking more about this and looked up the specs on my current "bad" panel in a Thinkpad..its an LG LP140WF3SPD1 and PWM free, and has a 25ms response time according to panelook.com but this laptop is still straining. I have put all sorts of panels in it from TN to IPS and everywhere from 5ms or so to 28-30ms with no success. So that feels like it can't be related to response time. Although as you know there are so many other factors who knows what combo is the trigger.
Seagull It is an over-simplification, but it might help to consider that a 30ms response time would equate to about 33frames per second (or Hz). If that monitor has a nominal refresh rate of 60fps (or Hz), then it may not respond fast enough to show any dithering.
It resembles the article I have linked in one of the other threads: https://www.lifewire.com/lcd-displays-and-bit-color-depth-833083 - they claim there's a clear relation between bit depth and response time of screens. Anyway it's hard for me to believe that every panel with over 8ms response time is 8 bit since almost no notebook panel is faster than this as I browse Notebookcheck reviews.
andc Anyway it's hard for me to believe that every panel with over 8ms response time is 8 bit since almost no notebook panel is faster than this as I browse Notebookcheck reviews.
I have spent a lot of time looking at panel specs on panelook.com and nearly all laptop panels I have seen are not true 8 bit panels but rather listed as 6+2 meaning 6 bits plus using dithering to get 2 more bits for a total of 8. For example here is the HD panel in a 2018 X1 Carbon http://www.panelook.com/B140HAN03.1_AUO_14.0_LCM_parameter_32138.html It just says "6+FRC" but many say explicitly "6+2 FRC"
Even the fancy HDR panel on the X1 Carbon 6th gen seems to not really be 12 bit HDR as it is advertised but rather 8+4. IF dithering is an issue then this is super relevant because most laptops are only 6 bit natively but being told to show 8-bits. But since laptop panels are "dumb" and require the gpu to tell them to dither I hope that means we can somehow force the output to the native color depth so the dithering doesn't happen.
But as usual it's confusing because IF dithering was the root cause it would seem logical to think an older 262k 6bit TN panel would be strain free and in my experience it is not...but to be fair I was unable to find one without PWM to avoid that variable. I don't know if that means those panels are still capable of dithering above 6 bits or if something else is going on.
Wow, I didn't know that this site contains such details. That's great that we can see what the actual bit depth of panel is if we know the model - thanks a lot.
Regarding PWM - I tend to believe every panel nowadays uses some kind of flickering - either as a whole and/or on individual (sub)pixels level. Actually I find panels using PWM better at first - the picture seems to be more stable, there's less snow, of course at the highest brightness setting. The ones that are supposed to be PWM-free (at least my phone doesn't see the lines) start causing issues within a matter of seconds / minutes. So I think they may employ some micro-PWM-like mechanism that doesn't look like on/off on oscilloscope tests, but the whole screen works all the time, especially when brightness gets reduced - something which I observed under microscope on lower brightness levels.
andc Unfortunately that site doesnt list PWM use as its info comes from manufacturers and they don't want to share that with anyone it seems. "Flickering" is a broad term and PWM backlight flickering is entirely different than dithering/FRC, but who knows if the results with regard to strain is the same or not. My personal experience has been that PWM is irrelevant since using known PWM free panels causes the same amount of strain as ones with visible PWM. It surely can't be GOOD for us but I've never seen someone solve their strain by simply removing PWM.
Sure, but at least low PWM can be easily tested with phone, and there are many reviews by Notebookcheck that cover various panels, so mixing results we can find panels that are 8-bit without FRC and PWM-free. That doesn't guarantee anything, but at least that's less enemies to defeat.
andc For me at least it doesn't matter if they are PWM free and 8-bit. I have seen such panels at shops and they still strained me. The Dell XPS 15 is an example. That's what makes the dithering thing confusing because if that IS a major factor then why would it be happening on a true 8-bit panel? Does that mean dithering isn't a cause of strain? Does that mean it's trying to dither even higher to 10-bit etc?
hpst
As usual, we can only guess, and try to find a needle in a haystack. I've been also thinking about refresh rates, frequencies, etc. For example I have some ear issues where particular frequencies tend to cause me physical pain (probably due to many years with headphones, etc.). There seems to be a relation between eye strain, sinus / jaw issues in some cases, both of them have also effect on ears. The pressure I can feel from staring at some laptops resembles sinus pain. So maybe our eyes are sensitive to specific frequencies, the same as ears, and these frequencies might have changed in recent years - due to dithering, new technology, more powerful gear, etc. Since we have different sight we may be sensitive to different frequencies - that would explain why someone can't use PWM screen with low refresh rate, while it doesn't bother other people. Just a thought, one of options.
JTL We are on the same page I think...I may have just expressed it wrongly. The laptop panel doesn't have built in dithering instructions or blue light/contrast/brightness whatever etc like a desktop monitor can so I called that a "dumb panel". As I understand it the panel's pixels have to "dither" to get the "super awesome vibrant" colors and thats what I meant by saying the gpu is making the panel dither. I understood the gpu is making it happen.
JTL Nearly every BIOS screen I have seen is on 100% brightness with no ability to reduce it so I can't stand looking at them just due to that...it's blindingly bright and hurts on anything but a super old dim CCFL. A 2014 Thinkpad I got for testing did surprisingly allow brightness controls to work in the BIOS but an update ruined that.