OpenType Features in the Real World: From Ligatures to Tabular Numbers

OpenType features can subtly elevate readability and polish when you enable the right ones in the right places. Here’s how to apply them without surprises.

Features Worth Enabling

• Standard ligatures (liga): Default for smooth text (fi, fl).
• Contextual alternates (calt): Better letterfit in running text.
• Kerning (kern): Usually on by default; confirm in your stack.
• Tabular numbers (tnum): Aligns digits in data and prices.
• Case‑sensitive forms (case): Fixes punctuation alignment in ALL CAPS labels.

body {
  font-kerning: normal;
  font-variant-ligatures: common-ligatures contextual;
}
.table { font-variant-numeric: tabular-nums; }
.label { font-variant-caps: all-small-caps; }

Use with Care

• Discretionary ligatures and stylistic sets: Great for branding, risky for dense UI.
• Oldstyle figures (onum): Beautiful in paragraphs; avoid in tables where alignment matters.

.article { font-variant-numeric: oldstyle-nums; }

Testing

• Verify feature availability for each font; many ship only partial sets.
• Check that enabling features doesn’t alter metrics unexpectedly.
• Validate PDF export or server rendering if you use it, because feature support varies.

Conclusion

Start with ligatures, kerning, and contextual alternates for body text. Add tabular numbers for data and case‑sensitive forms for labels. Layer more expressive features where brand allows.