What is the difference if any between increasing font size on a high res display and using a normal font size on a comparatively lower res display?

Question

This question has puzzled me for a long time. The new monitors in market have very high resolution and I find the need to increase font size while viewing webpages (Ctrl+ in Chrome). As far as text reading is concerned is there really any difference between using the high res display with a large font size or just using a normal font size on a lower resolution display?

Let's say previously I had a monitor of 1920x1080 resolution and used to read text at 12pt font. I upgraded to 2560x1440 resolution and now find that to make the text legible I have to increase the font size proportionately to something like 16pt. Am I really gaining anything from the high res monitor?

The benefit (if any) of a higher resolution display depends on the task. See 1 and 2 for examples. The earliest research on this question compared digital displays to paper. It's a big topic. This is a good place to find more recent research. — user1757436, Dec 16 '15 at 15:07

score 4 · Answer 1 · answered Dec 20 '15 at 00:02

If we're talking about the end result, anyway. Of course using more pixels requires more processing power, higher res screens have higher chance at dead pixels but less impact per pixel, but those are not what you're really asking, I think.

The idea isn't to use the same resolution on a smaller screen for better legibility, the idea is to have more pixels in the same area and thus more detail/sharpness. For example, computers have long been notoriously bad at rendering serif fonts, or anything with very thin lines, because you end up with details smaller than a pixel. This means you render that pixel in gray instead of black or white, and this means the image will feel softer, and blurry.

In extreme cases it's even impossible to represent just the basic forms of a letter. For example, an "e" of 4 pixels high can never have a counter (the hole in it). And an "E" of 4 pixels tall will lose either the top or bottom space:

Or how about the M, W, m and w in that font?

score 1 · Answer 2 · answered Nov 19 '15 at 20:55

Low resolution images tend to be harder to read than those that have smaller pixels (more pixels per inch). There's a limit though (much argued about) beyond which the human eye cannot differentiate the details. Apple's Retina display pixel densities are different for different use cases - watches and phones need to have higher densities than laptops because they are closer to your eyes (usually).

Anti-aliasing smooths out the shapes using grayscale pixels so some users can't see pixels even on lower-resolution monitors (e.g. under 220ppi).

Most displays have a fixed number of pixels and are best when supplied with exactly that from the computer/device. If you choose a lower resolution then the monitor will scale the image to fit it physical pixels. Not so bad if it just needs to double them but blurry if it needs to increase by fractions.

More pixels mean more work for the computer and the connection and some systems may run at a slower refresh rate at higher resolutions. In those cases you might be better of with a lower resolution, smaller fonts and a flicker free frame rate.

So give both a go and pick the setup that works best for you.

What is the difference if any between increasing font size on a high res display and using a normal font size on a comparatively lower res display?

2 Answers2