Point (Typography)
Modern equivalent
Traditional: 0.013837 in (0.3515 mm). Modern: exactly 1/72 in (0.3527 mm)
The base unit of type measurement, standardised in America in 1886 and accepted by British foundries in 1898.
Type is measured in points, and there are two of them. The traditional Anglo-American point is 0.013837 inches, or 0.3515 millimetres. The desktop publishing point, which arrived with computers, is exactly one seventy-second of an inch — 0.3527 millimetres, about 0.4 per cent larger.
That difference has never been resolved. Every book set in metal before the 1980s used the smaller point; everything set since uses the larger one. At twelve point the discrepancy is under a twentieth of a millimetre and nobody notices, which is precisely why two standards were allowed to coexist.
The standardisation is a rare case of Britain following America. The Type Founders Association of the United States adopted the pica of L. Johnson & Co. of Philadelphia in 1886 — the Johnson pica — and British foundries accepted the same system twelve years later, in 1898. Before that every foundry cut type to its own scale, and mixing suppliers in one job was a practical impossibility.