Baseline
The invisible line the letters sit on, and the line every vertical measurement in typesetting is taken from.
Near it
Overshoot
Descender
Baseline grid
Leading
Cap heightWhat it is made of
| what it is | the line the flat-bottomed letters stand on, capitals and lowercase alike, and the one line in a face that everything else is measured from | |
| round letters are the exception and are meant to be | an o or an e is drawn a little below it so it does not look short | |
| MEASURED ON OUR OWN SHELF, WHICH DID NOT HAVE ONE UNTIL 2026-09-24 | the flat feet of H, n and x sit at exactly 0 in 69 of the 84 files. The other 15 are named and meant: Stencil and Perforate cut their strokes into pieces, so no piece has a foot to put on the line; Extrude's letter stands on the line and its depth hangs below it, 177 to 200 units by weight; Engrave and Outline, drawn as a fine line round the Regular's silhouette, sit within 3 units of 1000 at their lighter and heavier weights because the fine line itself thickens. Until the fix every one of the 58 files that agreed with itself put its feet at -57 at Regular, uniformly wrong, which is invisible until two faces meet on a page | measured with fontTools over all 84 files on 2026-09-24, and looked at: the x of seven families rendered at 300px on a rule before and after |
| and the cause is one line of geometry, which is why it predicts rather than describes | every stroke in this foundry is a centreline with a width, and the ink runs half a stroke past the skeleton in the direction a terminal faces. A vertical stem cut with a butt cap is the ONE case where it does not, because the cut is horizontal and the ink stops on the line. So the H and the I are right by an accident of geometry and everything else overshoots | it predicted two different quantities and both landed to the unit across four weights of Drew Grotesk, measured on 2026-09-11 before the fix: a diagonal foot cut perpendicular to its own stroke dropped by (w/2) times sin 45, predicted 28.3, 40.3, 48.8, 58.7 against an x measured at 27, 39, 48, 57; a bowl or shoulder touching the line as a skeleton dropped by w/2, predicted 40, 57, 69, 83 against an n measured at exactly 40, 57, 69, 83. A cause that predicts numbers it was not fitted to is a cause, and the fix that follows from it put every one of those feet at 0 |
| what that means for the word itself | a baseline is the line flat feet sit on, which is what makes it a baseline rather than a coordinate. Until 2026-09-24 these faces had a skeleton and a stroke width, and the line was wherever the ink happened to land | found on 2026-09-11 while writing this record, the mechanism Helper Man's and checked against the files before it was written down; fixed by TYPEFOUNDER on 2026-09-24 by cutting every foot flat on the line, including a diagonal's down to 30 degrees, and proven by diffing every glyph's outline between builds and by looking at every glyph that moved |