Legibility and readability
Two different things: legibility is whether a letter can be told apart from another letter, readability is whether a page of them can be read for an hour.
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Text faceWhat it is made of
| legibility | whether a reader can tell one character from another | |
| readability | whether a reader can get through a page of them without effort | |
| a measurable rule for it, read from a primary | De Vinne, 1900: "For its legibility each character needs a fair relief of white space outside its stems. The distance between the stems of all the types in a word should be reasonably uniform. As a rule this distance is most satisfactory when the space between the stems of meeting letters is about the same as that between the stems of the letter m." | Theodore Low De Vinne, The Practice of Typography: Plain Printing Types (New York: The Century Co., 1900), p. 47, held by this house. It is quoted because it is one of the few statements about legibility anywhere that can be TESTED: it names two distances and says they should agree |
| and this shelf is tested against it | THREE OF 23 FAMILIES HOLD IT within 25 per cent: Drew Compact at 0.97, Drew Gazette at 1.06 and Drew Condensed at 1.10. The letter gap runs from 0.42 of the m's counter on Drew Extended to 2.21 on Drew Extrude, with Drew Slab at 0.62 | measured on the fixed shelf, 2026-09-29: the m at 400px, its two counters read off a scanline through the middle of its x-height, against the n's two sidebearings in the same units. Until 2026-09-24 this row said six families and Slab at 0.93, made by hand on a build replaced before it shipped; Compact at 0.99 and Extended at 0.44 reproduced on that shelf, which is how the method is known to be the same one. First confirmed by eye: set "mmmnnn minimum" in Extended and the letters crowd together while their own insides stay airy, which is the uneven rhythm the rule exists to prevent |
| two of the outliers are construction rather than spacing | Drew Extrude at 2.21 has its counter filled by the extrusion, and Drew Mono at 1.36 pads every letter to a fixed advance | so the honest count of families that could hold the rule and do not is eighteen |