Reading rhythm, not reading speed

Most advice about body text optimizes for one thing: how fast a reader can get through it. Shorter lines, generous leading, high contrast — all in service of speed, as though the goal of every page were to be finished as quickly as possible. For a terms-of-service page, sure. For anything meant to be thought about, speed is close to the opposite of the goal.

Line length is the clearest example. The usual rule of thumb is 45 to 75 characters per line, and most of the research behind it measures comprehension and fatigue over long reading sessions — genuinely useful constraints. But within that range there's still a choice: a 45-character line reads fast and choppy, closer to a list than a sentence. A 72-character line reads slower, because the eye has to track further before the next line break, and that extra half-second per line is doing something. It's giving a sentence room to breathe before the next one starts.

Leading as pacing, not just legibility

Line height gets treated as a pure legibility variable — tight leading is cramped, loose leading is airy, pick something in between and move on. But leading also sets pace. Tight leading pulls the eye down the page quickly, which is right for a table of contents or a set of instructions where you want the reader moving. Generous leading — 1.6, 1.65, even higher for a serif at a large size — asks the eye to pause fractionally longer at each line, which is right for an essay where the argument depends on the reader actually sitting with each sentence.

This is why a text-heavy personal essay and a reference doc shouldn't share type settings even if they share a typeface. They're not solving the same problem. One wants to be skimmed and returned to; the other wants to be read start to finish, once, slowly.

Designing for the pause

None of this means adding friction for its own sake — a page that's simply hard to read isn't "slow," it's just bad. The distinction is between friction that comes from difficulty and rhythm that comes from pacing. A wide-set serif at generous leading in a narrow column isn't harder to read than a cramped sans-serif at 100 characters per line. It's often easier. It just isn't trying to be fast, and for the kind of writing that rewards sitting with it, that's the right call.