Field guide / Rule 13 — Kerning
Kerning is the quiet, pair-by-pair adjustment that keeps certain letters from drifting apart — the A tucked under the V, the o nestled beside the T. Word ships with it switched off. Every document our engine sets has it on.
Every font sets a default width for each letter. For most pairs that spacing is right. But a handful of shapes — a capital that leans away like A, an open curve like o, a raised arm like T — leave an awkward hole beside their neighbour. Kerning is the table, built into the font itself, that nudges those specific pairs closer so the word reads as one even colour.
It is not the same as letter-spacing (tracking), which loosens or tightens every gap uniformly. Kerning touches only the pairs that need it, by the amount the type designer decided — AV, To, Wa, Yo, LT. Done well you never notice it; left undone, the gaps are the first thing that says a page was typed, not set.
The spacing is stored in the font, so switching kerning on costs nothing and needs no font you don’t already have. Yet Word, for reasons of legacy performance, ships with it disabled — you have to reach into Font → Advanced → Kerning for fonts and tick a box that almost no one knows is there. The result is that the overwhelming majority of Word documents render with the kerning tables in their fonts simply ignored.
We turn kerning on in every document we produce, so the fonts do the work they were designed to. It is the same instruction expressed three ways for three renderers:
In the Word file we set kerning in the document defaults, so it applies to every run — body, headings, tables — without you touching a menu. The PDF is set with Typst, which kerns as a matter of course. And the web reader asks the browser for kerning explicitly rather than trusting its default. Open the same document in any of the three and the letter-fit matches.
The one place we leave kerning off is monospaced code. A code font is
deliberately fixed-width so columns line up; kerning would fight that, so fenced blocks and inline
code keep every glyph on its grid.
In short
Kerning is spacing the font already knows — Word just forgets to use it. Everything our engine sets turns it back on, in the DOCX, the PDF and the reader alike, and leaves your code untouched on its grid.
Want to see it on your own text? Convert a document — the letters land where the type designer intended, no menu-diving required.