Design Nomenclature / Type
Sidebearing
Also called side bearing, LSB, RSB, advance width
- Type
- 2D
This entry has not been translated yet and is shown in English.
The space built into a glyph on either side of its outline. Left sidebearing plus the outline's width plus right sidebearing gives the advance width — how far the pen moves before the next glyph. Sidebearings are the font's own spacing; kerning is the per-pair correction applied on top of them.
In practice
Fixing spacing with tracking when the sidebearings are wrong is treating the symptom. If a face fits badly at text size, that is the face, and no CSS will repair it.
Not to be confused with
- KerningAdjusting the space between one specific pair of glyphs, correcting fits the sidebearings can't get right on their own — AV, To, r. — because the correction depends on the neighbour. Fonts ship kern pairs in the GPOS table; browsers apply them by default at text sizes.
- TrackingA uniform adjustment to the space after every glyph in a run — CSS letter-spacing. Size-dependent: display type usually wants negative tracking because the sidebearings were fitted for text, while small caps, all-caps runs and small labels want positive. Body text at text size almost never wants any.