The Point System
In 1737, Pierre Fournier le Jeune, a Parisian typefounder, proposed the first standard unit of measure known as the point. A point equals 1/72 of an inch, or .013836 inch. This measurement is used to indicate the size of type, and the space between lines of type, also known as leading. In 1785, Fermin A. Didot invented a larger point equal to 0.376 mm, which was adopted by the rest of continental Europe.
Picas are larger and are used to measure the length of a line of type and the width and depth of pages. A pica contains 12 points and is slightly less than 1/6 of an inch. There are 6 picas in 1 inch. Picas are used to indicate horizontal measurements such as column width and line ...