How Do You Pair Typefaces?

Tom Foley says you pair typefaces by matching structure first: where the letters come from, their vertical proportions, and their weight.

A modern or Bodoni-style headline, with high contrast, shoulders that blend into the stems, and fine serifs, pairs better with a grotesque, because that modern model evolved into grotesques and they share a structure. He starts with the calligraphic root. Trace the letters back and ask whether they come from a broad nib or a pointed nib, which other designers call expansion versus broad nib. Then match vertical metrics. The x-height, the ascenders, and the cap height should be as close as possible, so the features sit at the same height. Stem weights should work together. Weight range, color, and texture then narrow what can sit together. That helps most when one face is functional and the other is expressive.