[perching_aix]

> Unfortunately, that ( < 100 dpi when 300 dpi is considered barely acceptable for a print magazine)

I find this fascinating, because I recall school textbooks having visible dots, but I'm yet to experience what people refer to as "oh my god I'm seeing the pixel!".

It further doesn't help that when seated at a typical distance (30° hfov) from a ~23" 16:9 FHD display (96 ppi), you get a match (60 ppd) for the visual acuity you're measured for when an optometrist tells you that you have a 20/20 eyesight.

It's been of course demonstrated that eyesight better than 20/20 is most certainly real, that the density of the cones in one's eye also indicates a much finer top resolution, etc., but characterizing 96 ppi as so utterly inadequate will never not strike me as quite the overstatement.

[vel0city]

> I recall school textbooks having visible dots

In the color graphics or the text? I've read many textbooks with dithered color graphics but often had very sharp black and white body text.

[perching_aix]

I could pinpoint it anywhere if I looked close enough, but iirc it was mostly the images. Been a while, and these defects were rare and minor.

[mananaysiempre]

As far as I know, visible dots in color printing are usually due to limitations on the set of available colors and limited precision with which the separate stages that deposit those colors on the sheet can be aligned with each other, not due to the inherent limitations on the precision of each of those color layer. You get dots in photos, but not jagged lines in your letters. And 300 dpi is what your local DTP / page layout person will grumpily demand from you as the bare minimum acceptable input for that dithering, not what the reader will ultimately see. One way or another, 96dpi pixelated (or blurry) text in e.g. an illustration in a printed manual is really noticeable, and miserable to read in large stretches.

A more precise statement is perhaps that 96dpi is much too low to use plain sampling theory on the original outlines to rasterize fonts. It does work. The results are readable. But the users will complain that the text is blurry, because while there’s enough pixels to convey the information on which letter they are looking at, there are not enough of them to make focusing on them comfortable and to reproduce the sharp edges that people are accustomed to. (IIRC the human visual system has literal edge detection machinery alongside everything else.)

And thus we have people demanding crisp text when the requisite crispness is literally beyond the (Nyquist) limit of the display system as far as reproducing arbitrary outlines. Sampling theory is still not wrong—we can’t do better than what it gives us. So instead we sacrifice the outlines and turn the font into something that is just barely enough like the original to pass surface muster. And in the process we acquire a heavy dependency on every detail of the font display pipeline, including which specific grid of samples it uses. That’s manual hinting.

Seriously, leaf through the Raster Tragedy (linked in GP) to see what the outlines look like by the time they reach the rasterizer. Or for a shorter read, check out the AGG documentation[1] to see what lengths (and what ugliness) Microsoft Word circa 2007 had to resort to to recover WYSIWYG from the lies the Windows font renderer fed it about font metrics.

As for seeing pixels—I don’t actually see pixels, but what I do start seeing on lower-res displays after working on a good high-res one for a week or so is... lines between the pixels, I guess? I start having the impression of looking at the image through a kind of gray grille. And getting acclimatized to (only!) seeing high-res displays (Apple’s original definition of Retina is a good reference) for several days really is necessary if you want to experience the difference for yourself.

[1] https://agg.sourceforge.net/antigrain.com/research/font_rast...

[perching_aix]

Thank you for these resources, I'll read through them later.

While here, wasn't the original Retina defition also 60 ppd?