Oldstyle figures

A numeral set is a small alphabet, and like an alphabet it can be drawn tall or short. The default in most fonts is the lining set: every digit the same height, aligned to the capitals, drawn to sit beside MMXXIV without a step in the line. Oldstyle figures are the other drawing. Their bodies sit at the x-height, a few of them rise to the ascender, and the rest drop a tail below the baseline, so a number in the middle of a sentence has the same rhythm of ups and downs as the words around it. The usual pattern is 0, 1 and 2 at x-height, 6 and 8 rising, and 3, 4, 5, 7 and 9 hanging, though the exact set is the type designer’s call.

The reason to reach for them is the same reason a paragraph does not shout. Lining figures are drawn at the cap height, so a date inside running lowercase reads as five capital letters dropped into the sentence, and the eye stops at them. That is a virtue in a price, a total, or an interface number that has to be found at a glance, and a nuisance in a footnote, a citation, or an essay about the eighteen nineties. The same instinct produces small caps: capitals that have to appear inside a sentence get redrawn to lowercase height so they stop interrupting it.

Keep it clear of tabular figures, which answer a different question. Tabular is about width: every numeral given the same advance so that columns of numbers line up digit under digit, whatever the values are. Oldstyle is about height and shape: numerals redrawn to the proportions of lowercase so a number stops standing out in a paragraph. A face can offer either, both, or the two combined, which is why a good text family ships four figure sets, and why “proportional oldstyle” for prose and “tabular lining” for the accounts is a normal pair of choices rather than a contradiction.

In practice the switch is font-variant-numeric: oldstyle-nums, or the onum feature underneath it, and it does nothing at all in a face that carries no oldstyle set. That silence is the trap: the CSS is valid, the build is clean, and the numbers stay lining. Neither face this site loads carries the set, which is checkable and was checked, so the specimen on this page models the drawing instead: each hanging numeral is dropped by the difference between the digit height and the x-height, and each x-height numeral is scaled to it, with both rules ruled across the line so the heights can be read rather than taken on trust. A real oldstyle set is drawn, not shifted, and comes with its own widths.