Why does the font use text figures (“lowercase digits”)?

Question

Is there any particular reason why MSE uses text figures (according to Wikipedia also known as non-lining, lowercase, old style, ranging, hanging, medieval, billing, or antique figures or numerals)?

I for my part consider numbers like “1234567890” a lot harder to read than “$1234567890$”. And the different appearance between numbers in prose and numbers in $\LaTeX$ formulas looks somewhat inconsistent. Furthermore, the non-lining “0” is a lot easier to mistake for a letter “o” than the lining “$0$” for “O”.

On the whole it seems to me that the use of these numerals does look interesting and beautiful at first glance, but is rather annoying in actually reading these posts. As a consequence I tend to write all figures as $\LaTeX$ formulas in my posts. But this, too, feels wrong: either there is a deliberate and community-supported design decision that text figures should be used, in which case I shouldn't go against that decision without more reason. Or the way I avoid text figures is preferred, in which case this should be the default as well, to avoid the overhead of dolar signs all over your post as well as to allow newcomers to write nicely styled texts without having to know about formula syntax.

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Edit: Thanks to the comment by @40 votes I now realize that the Georgia font does not contain lining figures, so switching this aspect of the design would not simply be a change to some config setting, but a change in the font used throughout the page, with everything that entails. The concerns voiced above may even warrant such a radical change, though.

Answer 1

The text figures should stay

This is one of two “just-vote” answers which I create to allow people to express their opinion on whether or not the use of text figures by default makes sense. Feel free to vote for one of them if you have a sufficiently clear gut feeling one way or the other. If you want to express reasons, arguments, case distinctions or in fact anything but a simple vote, please write a normal answer instead (or in addition to voting). Avoid commenting on this answer here, since the only relevant aspect is the vote count associated with it.

Answer 2

The text figures should go away

This is one of two “just-vote” answers which I create to allow people to express their opinion on whether or not the use of text figures by default makes sense. Feel free to vote for one of them if you have a sufficiently clear gut feeling one way or the other. If you want to express reasons, arguments, case distinctions or in fact anything but a simple vote, please write a normal answer instead (or in addition to voting). Avoid commenting on this answer here, since the only relevant aspect is the vote count associated with it.

Answer 3

I agree with the basic premise: 3.14159265358979323846 is not how I expect $\pi$ to be written. While we do have MathJax $3.14159$ and monospace 3.14159, the latter adds background while the former comes with the overhead of JavaScript and $ markup.

As far as I can tell, only two math-heavy SE sites use serif for the body of posts (both use Georgia): Mathematics and Electrical Engineering. The latter has a feature request Change the way digits are displayed, get rid of non-lining digits and sort-of followup Didn't we switch the site style to use “lining” numerals? Apparently, no action was taken regarding EE feature request.

Times New Roman has lining figures, but I don't think we want it. Here is a Times mock-up of the OP (not in the sense of mocking the OP :).

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Clearly, Georgia is the best serif font among the core web fonts. Using a downloadable web-font comes with its own overhead cost (the delay before the font appears is a major irritation for me personally). I'm not confident that SE will invest the necessary time and money into implementing paid web fonts on a site with zero revenue. See Aarthi's answer to Are requests for changes to the site design ignored by default?

Update the UNIX.SE request Question title font renders 0 much like o has been addressed by changing their title font from Georgia to Liberation Serif (see the answer by Shog9). Would this be an improvement for us? The font looks much like Times New Roman to me...

... And sometimes, when looking at the main site, I think Comic Sans MS is the right font for it.

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Answer 4

A bit of research showed that there exists a “Georgia Pro” which has several added features. This news item from 2011 explicitely mentions numerals:

The original Georgia and Verdana fonts differ in their default settings for numerals. While Verdana defaults to lining figures, which rest on the baseline and commonly share the same height as capital letters, Georgia defaults to old style figures, which have varying heights to better harmonize with lowercase characters. With the release of the latest fonts, the new Georgia Pro is now consistent with Verdana Pro, as both use lining figures as their default settings.

Using these fonts would come at a cost, but as far as I can tell the cost seems to be independent of the size of the site, and might be acceptable for the third-largest SE site. Of course, that is not my decision to make, I'm just thinking. Using these fonts would also mean that MSE would have to embed them as downloadable web fonts, which might require some more work on the side of the admins to get this set up.

Answer 5

Just to express my opinion: I don't like to type two dollar signs when I write numbers. No to mention this is counter-habit of writing $\mathrm{\LaTeX}$...

Besides, it is so easy to type $1$ as \$!\$.

Answer 6

Seeing the nearly equal split between lining and text figures in the poll, I think this is something that users should be able to choose on their side. Below I give CSS rules with their implementation for Firefox and Chrome. They change the font of posts and comments to Times New Roman, which has lining figures. Note that Times needs a larger font size to be as legible as Georgia. The site uses Georgia 15px; the comparable size for Times (on my computer at least) is between 16px and 17px.

Some users may prefer something else, e.g., Arial 14px for consistency with MathOverflow.

For Firefox users

Locate or create the folder named chrome in user profile as described here, create userContent.css in that folder, and enter the following:

@-moz-document domain(math.stackexchange.com) {
  div.post-text p { 
  font-family: 'Times New Roman', Times, serif !important;
  font-size: 16px !important;
  line-height: 21px !important;
}
  span.comment-copy { 
  font-family: 'Times New Roman', Times, serif !important;
  font-size: 14px !important;
  line-height: 18px !important;
}
}

For Chrome users

Locate your custom.css file; on Windows 7 its path is

[disk]:\Users\ [your user name] \AppData\Local\Google\Chrome\User Data\Default\User StyleSheets\Custom.css

Put the following code there:

td.answercell > div.post-text p, td.postcell > div > div.post-text p { 
  font-family: 'Times New Roman', Times, serif !important;
  font-size: 16px !important;
  line-height: 21px !important;
}
td.comment-text > div > span.comment-copy { 
  font-family: 'Times New Roman', Times, serif !important;
  font-size: 14px !important;
  line-height: 18px !important;
}

Unlike Firefox version, this one is not site-specific: it will change the post font on all SE sites. Maybe it's not so bad if you like consistency.

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(Aside, from an older version of this answer)

The problem with antique rendering of digits is not that large in scope. It is common among $\LaTeX$ users to enter numbers in math mode (TeX.SE discussion). For example, when writing "multiplying $\theta$ by $2$, we get $2\theta$" you want to make sure that both $2$s will look the same under all circumstances. Leaving the first one in text mode saves two dollar signs, but opens the possibility of inconsistent appearance.

Answer 7

We could use STIX. This is the font MathJax will use by default, so it should give the most consistent integration of formulas and written texts. And the font should contain many special Unicode symbols useful for mathematics, and many mathematicians will have these fonts installed. For those who don't have it installed, a downloadable version can be provided, to be automatically used by browsers without any user intervention, but perhaps with a little delay on the first visit to the site.

Changing the font of the above post to STIXGeneral, it looks like this on OS X Firefox with a computed font size of 13px for the text

and like this on Linux with a computed font size of 15px for the text:

As you can see, the font looks a lot thinner than Georgia, and still a bit thinner than Times New Roman. More notably, it is a lot wider than Times New Roman. In fact, the horizontal spacing looks similar to Georgia, I think. I am somewhat surprised by how different the same font renders on different OS. It might have something to do with how the hinting is handled, or what the autohinter will do in the absence of hints.

As you might have noticed, the math number in the above snapshot still looks bigger. This is because MathJax styles one of its many <span>s with font-size: 108%. I guess there should be ways to disabuse it of this practice, to make the font sizes completely equal for formulas and other text.