Pixel Density & Manual Pixel Refresher Questions

[BoredErica]

Got a lot of confusion here so bear with me on the many questions that need answering:

1. I see a lot of people talk about pixel density as if it's a major factor in image sharpness. (I even see some people think pixel density is dependent on viewing distance, which is absurd.) I don't agree with this. We don't judge how sharp a display is based on how easily we can see the pixels with eyeballs 1cm from the display because nobody uses the display that way. Rather, I think it's pixel density vs distance or PPD that matters for our perceived sharpness. So at the same FOV, I think perceived sharpness is the same. Is this correct?
I think at equal FOV, the sitting difference compensates for difference in pixel density if both displays are 4k.

There are many posts on other forums of people asking whether "1080p is too blurry for 32in but ok for 27in" which to me implies the user sits at identical distances no matter the display. Which can happen if user is super limited on flexibility of their setup, but usually seems like an unrealistic use case given how often it's brought up. I don't see people complain that 83in TVs are terrible because they're so blurry because the pixel density is lower than a 40in 1080p display. I don't see home theater enthusiasts try to downgrade to smaller and smaller TVs for clarity.

Please note, I'm not at all talking about limits of human vision here or referencing those graphs that allege that past a certain distance, a higher resolution is useless.

OFC, people often compare WOLED 42in TV to a 27in IPS display. But this comparison is unfair to me because of differing subpixel structures and misc things like graininess or banding on WOLED TVs. I don't think deciding between a 42in screen or 27in screen is a tradeoff between perceived clarity and immersion.

2. I'm still unsure what the difference between short auto pixel refresher after turning off display after few hours of use is on LG C2 vs manual pixel cleaner that takes a long time (and is auto scheduled after ... 2000hr? of use?). People seem to think the shorter refresher is harmless. Some say it's necessary for burn in prevention. A thread on r/OLED_Gaming had multiple people blaming a user's burn in on using their TV 12hr straight rather than taking breaks to allow for short pixel refresher. Is this true at all?

And the long pixel refresher people say harms the longevity of the panel on paper, and so should only be run when necessary. Some say this isn't true, all it does is adjust voltages based on pixel wear. Which is true, or both? A friend of mine thinks playing content that has black bars will never cause "burn in" even if the areas that are barely used would be brighter because the manual pixel refresher should forcibly wear out the pixels that keep showing the black bars so they are at similar levels of wear compared to pixels around it. Is this true? I read Rting's B6 test w/ Rtings logo which had letterbox for little less than half of the video loop each loop and I could where letterbox was, despite I think, manual pixel refresher having been run sometime during the test.

I think this debate goes back to black wallpaper vs varied content wallpaper debate (question being, which is better for longevity of display.)

[bumbeen]

"1080p is too blurry for 32in but ok for 27in" which to me implies the user sits at identical distances no matter the display. Which can happen if user is super limited on flexibility of their setup, but usually seems like an unrealistic use case given how often it's brought up.

If you move the monitor further away when the screen is larger, then there was no point in buying the larger screen in the first place. Comparisons can only be made when the distance from the viewer is fixed

[BoredErica]

"1080p is too blurry for 32in but ok for 27in" which to me implies the user sits at identical distances no matter the display. Which can happen if user is super limited on flexibility of their setup, but usually seems like an unrealistic use case given how often it's brought up.

If you move the monitor further away when the screen is larger, then there was no point in buying the larger screen in the first place. Comparisons can only be made when the distance from the viewer is fixed

I don't agree with this at all. Nobody still sits 20in away from a projector and if somebody upgrades from an old 19in to 24in to 32in display, they will most likely be sitting farther back or there will be ergonomic problems. If what you say is true, then just sit super duper close to a small display. Nobody actually thinks sitting close to a 27in monitor makes it feel like a movie theater. Regardless of preference, they are distinctively *different* experiences. I think a larger screen viewed further away is more immersive, at least for 27 vs 42in displays which I tested side by side. I'm quite convinced of this so am not interested in debating this unless one of the usual experts want to weigh in.

[bumbeen]

I don't agree with this at all. Nobody still sits 20in away from a projector and if somebody upgrades from an old 19in to 24in to 32in display, they will most likely be sitting farther back or there will be ergonomic problems. If what you say is true, then just sit super duper close to a small display. Nobody actually thinks sitting close to a 27in monitor makes it feel like a movie theater. A larger screen viewed further away is more immersive, at least for 27 vs 42in displays and I'm quite convinced of this so am not interested in debating this.

Well you will remain mystified by people asking if 32" is too large for 1080p then

There is no screen size relation to pixel density/screen door effect, it is a fov/distance relation. This is why screen distance calculators ask you for 1) resolution, and 2) screen size and then provide you with a resulting distance. Because the goal is to have an equivalent FoV for all screen sizes at a given resolution, ideally the maximum fov that allows you to resolve every pixel but without creating screen door effects. So for a given resolution, a smaller screen needs to be closer than a larger screen. If you buy a larger screen at the same resolution, you are doing so because you are unable to move your smaller screen closer to your face. If your smaller screen is already at the minimum distance from your eyes to fully resolve the image, then there is zero reason to buy a larger display simply to have it further away from you. Zero reason is a bit of an overstatement, there is some comfort gained from having the focus distance further from your eyes. But as far as SDE/Pixel density is concerned there is nothing to be gained, you must raise the resolution.

If what you say is true, then just sit super duper close to a small display.

Like a VR headset