Deeply negative LSB

Definition

Left sidebearing is more negative than -100fu — usually a bug from a mass-spacing pass. Modest negatives (e.g. -20) are normal for italic letters that lean.

How Patens surfaces this

The Patens audit module checks for sidebearing-deeply-negative-lsb across five teaching surfaces: the edit-panel inline issue list, the project-wide audit page, the release pre-flight check, the family hub, and the home-page project tile. Every surface shows the same plain-English explanation and links back to this page. This rule is detection-only — there's no automatic fix because the correction is design-dependent (it requires a judgment call about the glyph's intended shape or the font's intended behaviour). The audit message links to the specific glyph or field that needs attention.

Run this check yourself

Patens runs every audit rule live as you draw — including this one. The editor (in private alpha) shows sidebearing-deeply-negative-lsb firing on real glyphs, or check your own work from the CLI:

npx patens audit your-project.font.json

Related rules in Metric alignment

• capheight-misaligned Cap-height misaligned
• sidebearing-class-drift-lsb Sidebearing class drift (LSB)
• sidebearing-class-drift-rsb Sidebearing class drift (RSB)
• sidebearing-deeply-negative-rsb Deeply negative RSB
• xheight-misaligned x-height misaligned