Swash

A swash is an alternate drawing of a letter with a stroke run out past where the letter needs it: the tail of a Q swung out under the next word, the leg of an R or a K carried away to the right, an entry stroke curling in from the left of a capital. The shapes come from chancery italic, where a pen leaving the paper at speed produced exactly these exits, and they belong to italic capitals more than to anything else. A swash is not a different letter and not decoration laid on top of one. It is the same glyph redrawn, which is why substituting it changes the fit of the line as well as its texture.

Getting one is a font question before it is a CSS question. Swash forms live in the font file under the swsh feature (with cswh for the contextual case), reached from CSS with font-variant-alternates: swash(…) or by setting the tag directly. Ask a face that carries no swash table and nothing happens at all: the text renders in the ordinary forms with no warning, which is the standing trap of OpenType features generally. It is the same machinery that gives you a ligature and small caps, doing a different job in each case: a ligature fuses colliding letters into one drawing, small caps supply short capitals with the weight of lowercase, and a swash supplies a more elaborate drawing of a letter that already fit.

The rules of use are old and still hold. A swash capital is for an initial, a final, or a single display word, not for a run of text, because the flourishes were drawn to have empty space to travel through and a line of them collide with each other. Never set a whole word in swash capitals; the classic advice is blunter still, that swash caps are never used with other capitals at all. Contextual swash exists precisely to enforce this, swapping the ornate form only where the position in the word allows it. The register they carry is festive and old, which is why they turn up in wedding stationery, wine labels, and the letterforms of Art Nouveau, and why they read as costume anywhere else.

One note about the specimen on this page. None of the faces this site loads carries a swash table, and a screenshot of a feature silently failing would teach the wrong thing, so the letters there are drawn as vector paths rather than set in a typeface. The construction is honest about what a swash is, an exit stroke extended, but the drawing is this site’s and not a foundry’s.