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Comment by mac-mc | Hacker News Reader

Has anyone done studies showing how much people notice the difference between 60 and 110 PPD photos for example? There are many people who have a hard time articulating 30 vs 60 PPD as it is with computer monitors. How much of a diminishing return is it to go beyond 60 PPD?

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This study popped up: https://www.techhive.com/article/578376/8k-vs-4k-tvs-most-co...

In summary, with an 88" screen at a distance of 5 feet, some viewers rated 8K content (118 PPD) higher on average than equivalent 4K content (59 PPD), particularly those with better than 20/20 vision (~60 PPD). Most would not notice. It wasn't directly tested but I'd guess most people do notice the difference between 30 and 60 PPD, but only those with above average eyesight will see improvements beyond that.

Nice find. TV image quality is usually so imprecise (compression, lack of text), I would suspected computer displays to be more noticeable.

I don't know about studies, but I'm pretty sure there is a large difference between very high contrast edges (worst case: text rendered without anti-aliasing) and photos or even videos, where there usually aren't any high-contrast high-frequency edges (black pixel next to white pixel). Since anti-aliasing is standard in font rendering and pretty common in computer games, I don't think very high PPD content would often be noticable.

On the monitor I mentioned, this text is about 15-20 pixels tall mostly-white on mostly-black, and I can read it from ~4 feet away.

(website says that is ~186 PPD)

That makes sense. Given that the smallest legible fonts are around 5 pixels tall, that's 3-4x less PPD than your monitor offers at 4 feet, so you'd need ~46-62 PPD eyesight to be able to read the text. 20/20 at 60 would be more than sufficient.

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