Why a serif, and why Vollkorn.

Vigil shipped as a sans and nothing else. A text sans that disappears at 16px and shows its personality at 96 was the whole brief. Set real things in it — a long article, a set of release notes, a page of documentation — and you run into the thing every sans-only system runs into. There is no second voice. Every quote, every aside, every footnote has to be signalled with size or weight or color, because the typeface itself only has one register.

Italics help. They are not enough. An italic is a change of tone inside a sentence; what long-form writing wants is a change of material between blocks. Body copy in one family, interface in another. That's the oldest layout convention there is, and it exists because it works.

The problem with pairing

The usual fix is to pair your sans with someone else's serif. The candidates are not the problem; the arithmetic is. Two typefaces drawn by two people at two different times almost never share an x-height, and they never share a line box. So you spend your afternoon nudging: serif at 17.5 to match the sans at 17, one family's line-height at 1.6 and the other at 1.52, a negative margin on the pull quote because its cap sits four pixels high.

Every one of those nudges is a decision that should have been made once, in the font, instead of a thousand times, in the CSS.

So the goal stopped being "find a serif that looks nice beside Vigil" and became "make a serif that measures the same as Vigil." Same cap height. Same x-height. Same descender. Same line box. Drop it in at the same size on the same baseline and nothing moves.

Why Vollkorn

Vigil Serif is not drawn from scratch, for the same reason Vigil itself is not: the alphabet is not the hard part. What it needed was a skeleton with the right temperament, released under a license that lets you rebuild it.

Friedrich Althausen's Vollkorn is that. It was first published in 2005, one of the first genuinely good free serifs, it has been maintained and expanded for twenty years, and it carries about 2,300 glyphs across Latin, Cyrillic and Greek — a range it would take me years to draw and longer to kern. Critically, it isn't precious. It's a warm, sturdy, slightly rustic bread-and-butter serif; the name means "wholegrain." It was built to be read in long stretches, which is exactly the job.

It also had the one quality I couldn't manufacture: it doesn't fight a geometric sans. A high-contrast Didone beside Vigil looks like a costume change. Vollkorn's moderate contrast and open counters sit next to a large-x-height geometric sans without either one shouting.

What reproportioning actually means

This is the part I underestimated. Matching another typeface's metrics is not a scale factor. Vollkorn's proportions are its own: relative to Vigil the x-height sits differently against the caps, and the ascenders don't stop where Vigil's do. Scaling the whole thing until the x-heights agree gives you caps that are too tall, a descender that's too deep, and a line box that no longer matches — you've traded one mismatch for three.

So the work was structural, one horizontal at a time. Set the cap height to Vigil's. Pull the x-height up until the ratio matches — Vigil's is 0.714, and that number is the whole reason the two look like relatives rather than neighbors. Bring the ascenders down to stop flat on the cap line, as Vigil's do, so caps and lowercase share one ceiling. Hold the descender at Vigil's depth. Then rebuild the vertical metrics so the line box lands on 1.200 em, identical to the sans.

What I deliberately did not do is squeeze the widths. The serif sets about six percent wider than Vigil in lowercase, and it should: that extra width is the serifs. Forcing it to Vigil's set width would mean narrowing the skeleton to make room for the brackets, which is how you get a serif that looks starved. Six percent is the honest cost of the serifs, and it's small enough that a paragraph reflows by a word or two rather than a line or two.

One consequence worth knowing, because it will bite anyone who pairs them: at the same nominal weight, the serif reads heavier. Serifs add ink at every terminal. So the stem-matched pairing is serif 300 beside sans 400 — the serif steps down one stop to look like it weighs the same.

What it's for, and what it isn't

Content. Articles, documentation, books, quotes, footnotes, tables of figures where old-style numerals keep the column quiet. Above roughly fourteen pixels it is a better reading face than the sans, and the italic is a real italic with its own drawings, not a slant.

Not interface. Below fourteen pixels the serifs thicken into the counters and dense rows stop scanning; tracked-out all-caps navigation pulls the serifs apart until each word reads as separate marks. The division I've settled on is the simplest one available: content in the serif, interface in the sans.

Where it stands

Version 1.100: variable roman and italic on one axis from 200 to 900, and sixteen hinted statics. Small caps, old-style, lining and tabular figures, fractions, superscripts and subscripts all work. It is free under the SIL Open Font License, like the sans, because Vollkorn was free under it first. That's not generosity on anyone's part; it's the license doing exactly what it was written to do, twice.

Go look at it and tell me what breaks.

— Keno Vigil, Cary, North Carolina