4 ms·

This is helpful for estimating how much higher display resolutions are still perceivable and when we enter the territory of "marketing bullshit". For example:

This is helpful for estimating how much higher display resolutions are still perceivable and when we enter the territory of "marketing bullshit". For example: - 40 cm view distance (e.g. smartphone): 300 ppi is roughly the maximum that's useful - 100 cm (e.g. desktop monitor): about 200 ppi https://www.nature.com/articles/s41467-025-64679-2/figures/2 https://www.nature.com/articles/s41467-025-64679-2/figures/2

cubefox 1y ago
About 15 cm view distance for smartphones is pretty normal for me (shortsighted with glasses) on websites where the text is very small, e.g. Hacker News.
- samat 1y ago
  I’ve started using text scaling on HN (Cmd++ on Mac, available on mobile, too) and it’s much easier to read and pleasant to the eye this way.
  - cubefox 1y ago
    Oh, that's a great idea. I see Firefox also has this in the settings under Accessibility. I guess I never looked there because I don't think of myself as disabled. (Maybe I should.)
    - bombcar 1y ago
      More and more - especially on Apple products - Accessibility is the "customization" menu, not the "disabled support" it used to be. Size increases, animation decreases (when your iPhone is getting old, turn off animation and behold it operating super fast!), etc can all be found there. I zoom websites until they "feel right" which is usually something close to "they are as wide as the window I have them in" - HN is a few taps up from "actual size".
    - trenchpilgrim 1y ago
      given enough time we all become disabled
trenchpilgrim 1y ago
I use my phone way closer than 40cm all the time...
- dev_hugepages 1y ago
  You may have untreated myopia, or need to use a bigger font size (HN is guilty of this!)
  - trenchpilgrim 1y ago
    No I just sometimes use my phone while lying down lol
noosphr 1y ago
I remember those numbers being a third that 20 years ago. Either we have evolved brand new eyes without noticing or you are just talking about the current state of the art like it's the limit of human vision. Put another way look at 300ppi prints and 1200ppi prints. The difference is night and day at 30 cm viewing.
- ncruces 1y ago
  ppi pixels ≠ dpi dots You don't need 1200ppi for a nice 1200dpi print; even 300ppi may be enough.
  - adrian_b 1y ago
    For printing photos, you are right that a 300 ppi printer is better than an 1200 dpi printer. On the other hand, for printing text, an 1200 dpi printer has the quality of an 1200 ppi printer. Many well-designed traditional typefaces have relied on optical effects caused by details that require for being printed a resolution higher than that at which the human eye can distinguish a set of bars from an uniform background (which is the object of TFA). For instance, in some typefaces the edges of the strokes are concave or convex, not straight, which could be rendered in a computer display only by either a much higher resolution or by more sophisticated pixel preprocessing methods (in order to simulate the effect on the eye). Whenever such typefaces are displayed at a lower resolution, i.e. on computer monitors, they are very noticeably uglier than when printed on paper by traditional metal printing methods or even by a high-resolution laser printer.
    - cubefox 1y ago
      A 1200 ppi display can use anti-aliasing, e.g. grey scale edges on text, while a 1200 dpi printer can't, I'm pretty sure. So the former has better quality.
jl6 1y ago
Higher ppi on mobile is still useful if it enables “manual zoom” (i.e. move your head closer). I do this with Google Sheets on mobile all the time, as I like to have a lot of the sheet displayed at once to see the overall structure, and then peer closer to read the text.
adrian_b 1y ago
You want to say "the minimum that is useful", because you want a resolution at least equal with that, to not see the pixel structure. A 27" monitor has a height around 17", i.e. about 43 cm, and for watching a movie or anything else where you look at the screen as a whole the recommended viewing distance is twice the screen height, i.e. about 86 cm. At this distance, the resolution needed to match the human vision is provided by a height of slightly less than 3000 pixels by this study, but by about 3300 pixels by older studies. In these conditions you are right, the minimum acceptable resolution is around 200 ppi. This means that a 27 inch 5k monitor, with a resolution of 2880 by 5120 pixels, when viewed from a distance twice its height, i.e. about 86 cm (34 inch), provides a resolution close, but slightly less than that of typical human vision. (That viewing distance that is double the height corresponds to the viewing angle of camera lenses with normal focal length, which has been based on studies about the maximum viewing angles where humans are able to perceive a correct perspective when looking at an image as a whole.) However, when not watching movies, but working with text documents, you normally stay closer to the monitor than that, so even a 5k monitor is not good enough (but an 8k monitor may be enough, so that might be the final monitor resolution, beyond which an increase is useless).

cubefox 1y ago

About 15 cm view distance for smartphones is pretty normal for me (shortsighted with glasses) on websites where the text is very small, e.g. Hacker News.

samat 1y ago
I’ve started using text scaling on HN (Cmd++ on Mac, available on mobile, too) and it’s much easier to read and pleasant to the eye this way.
- cubefox 1y ago
  Oh, that's a great idea. I see Firefox also has this in the settings under Accessibility. I guess I never looked there because I don't think of myself as disabled. (Maybe I should.)
  - bombcar 1y ago
    More and more - especially on Apple products - Accessibility is the "customization" menu, not the "disabled support" it used to be. Size increases, animation decreases (when your iPhone is getting old, turn off animation and behold it operating super fast!), etc can all be found there. I zoom websites until they "feel right" which is usually something close to "they are as wide as the window I have them in" - HN is a few taps up from "actual size".
  - trenchpilgrim 1y ago
    given enough time we all become disabled

trenchpilgrim 1y ago

I use my phone way closer than 40cm all the time...

dev_hugepages 1y ago
You may have untreated myopia, or need to use a bigger font size (HN is guilty of this!)
- trenchpilgrim 1y ago
  No I just sometimes use my phone while lying down lol

noosphr 1y ago

I remember those numbers being a third that 20 years ago. Either we have evolved brand new eyes without noticing or you are just talking about the current state of the art like it's the limit of human vision. Put another way look at 300ppi prints and 1200ppi prints. The difference is night and day at 30 cm viewing.

ncruces 1y ago
ppi pixels ≠ dpi dots You don't need 1200ppi for a nice 1200dpi print; even 300ppi may be enough.
- adrian_b 1y ago
  For printing photos, you are right that a 300 ppi printer is better than an 1200 dpi printer. On the other hand, for printing text, an 1200 dpi printer has the quality of an 1200 ppi printer. Many well-designed traditional typefaces have relied on optical effects caused by details that require for being printed a resolution higher than that at which the human eye can distinguish a set of bars from an uniform background (which is the object of TFA). For instance, in some typefaces the edges of the strokes are concave or convex, not straight, which could be rendered in a computer display only by either a much higher resolution or by more sophisticated pixel preprocessing methods (in order to simulate the effect on the eye). Whenever such typefaces are displayed at a lower resolution, i.e. on computer monitors, they are very noticeably uglier than when printed on paper by traditional metal printing methods or even by a high-resolution laser printer.
  - cubefox 1y ago
    A 1200 ppi display can use anti-aliasing, e.g. grey scale edges on text, while a 1200 dpi printer can't, I'm pretty sure. So the former has better quality.

jl6 1y ago

Higher ppi on mobile is still useful if it enables “manual zoom” (i.e. move your head closer). I do this with Google Sheets on mobile all the time, as I like to have a lot of the sheet displayed at once to see the overall structure, and then peer closer to read the text.

adrian_b 1y ago

You want to say "the minimum that is useful", because you want a resolution at least equal with that, to not see the pixel structure. A 27" monitor has a height around 17", i.e. about 43 cm, and for watching a movie or anything else where you look at the screen as a whole the recommended viewing distance is twice the screen height, i.e. about 86 cm. At this distance, the resolution needed to match the human vision is provided by a height of slightly less than 3000 pixels by this study, but by about 3300 pixels by older studies. In these conditions you are right, the minimum acceptable resolution is around 200 ppi. This means that a 27 inch 5k monitor, with a resolution of 2880 by 5120 pixels, when viewed from a distance twice its height, i.e. about 86 cm (34 inch), provides a resolution close, but slightly less than that of typical human vision. (That viewing distance that is double the height corresponds to the viewing angle of camera lenses with normal focal length, which has been based on studies about the maximum viewing angles where humans are able to perceive a correct perspective when looking at an image as a whole.) However, when not watching movies, but working with text documents, you normally stay closer to the monitor than that, so even a 5k monitor is not good enough (but an 8k monitor may be enough, so that might be the final monitor resolution, beyond which an increase is useless).