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Comment by jchw | Hacker News Reader

But wait, I thought CRTs don’t really have resolution per se. Especially for horizontal, I’d imagine things are quite flexible. The same might not be true of an NTSC signal, where 80 columns probably would not work terribly well, but why would it matter for 72 vs 80 vs etc.?

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don’t really have resolution per se

A CRT doesn't have to have resolution in the sense of pixels per inch (although many of them do). However "resolution" is a more general limit on how far away two distinct points can be.

A discrete grid of pixels imposes one kind of limit. But another kind of limit is that two slightly fuzzy dots will become indistinguishable if they blur into one another sufficiently.

Yeah, this was my understanding, but I kept it vague since I don’t claim to be any kind of expert. Otoh, I suspect for this reason that the choice of 80 columns particularly was not motivated by CRT limitations. Could be wrong but it’s not like CRT tech was new in the 70s, and we’re talking about monochrome here.

Most monitors were pretty small. So too many characters per horizontal real estate would have been hard to read.

The core claim of this article is that this is not why 80 was picked though

VT220s had a 132 column mode. It was readable, albeit not as readable as 80 columns.

So did vt100/vt102 - though it may have been an option on vt100, and a reverse video mode. It was only vt52 stuck at 80.

It was readable, but not something for your default setting - 10 mins was more than enough!

However, the character matrix was the same for both modes, just the letter spacing was different. – Did this cause certain characters to bleed one into another at times, or was this just a general readability issue?

Hard on the eyes: https://imgur.com/IYULtxA

Ah, I see. Apparently, more of a general contrast / density / grey level issue. Also, probably some issues with bleed and character separation, but this may be also due to the photographic exposure. Thanks for linking the image!

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