Legibility

Whether the words can be read without effort. It is not the same as beauty, and when the two disagree, legibility wins.

Legibility is measurable in a way beauty is not: can the intended reader, at the intended distance, in the intended light, read this without effort? Size, contrast, spacing and the letterforms themselves all answer to that question. Everything else in typography is negotiable; this is not.

The clause with teeth is the second one: when legibility and beauty disagree, legibility wins. The ivory on ink of these pages was tuned until it read effortlessly first, and only then admired. A beautiful surface that strains the reader is a private pleasure billed to someone else.