Chapter 43. Traditional and Metric Typographic Units
Typography has been around longer than the SI system. Printers in various countries invented many different measurement systems and a lot of them are still around. But they are mixed with computerized units as most typesetting is now computerized.
Truchet is an old French system that has not been used for centuries.
Didot is the name of a family of French printers, punch-cutters (punches are the hard metal tools used to make molds for metal type), and publishers. Their products became the basis for the measurement system used in Europe for centuries. This was based on the old French royal inch.
ATA is used in the United States and the United Kingdom, and is sometimes called the Anglo-Saxon point ...