Father Truchet

Sébastien Truchet
Sébastien Truchet
Born	1657 Lyon, France
Died	5 February 1729 France
Nationality	France
Fields	Mathematician, hydraulics, graphics and typography
Institutions	France under Louis XIV
Known for	Proportion of typefaces, plane tiling, sundials, channels, weapons
Influenced	Pierre Simon Fournier, François-Ambroise Didot, Giovanni Battista Bodoni

Father Sebastian Truchet (French: Père Sébastian Truchet, 1657 – 5 February 1729), born Jean Truchet, was a French Dominican priest born in Lyon, who lived under the reign of Louis XIV. He was active in areas such as mathematics, hydraulics, graphics, typography, and for many inventions.

Truchet was born in 1657. In 1693, he was selected by Abbé Bignon to assist his commission investigating the feasibility of compiling a description of all France's artistic and industrial processes for the minister Colbert. For his assistance, he was named an honoraire of the French Royal Academy in 1699.

Truchet died on 5 February 1729, with the Descriptions of the Arts and Trades still incomplete.

Alongside the royal typographer Jacques Jaugeon, Truchet studied the proportions of typefaces using the French line ( ¹⁄₁₂ French inch), a measurement derived from silversmithing. The commission then invented the first typographic point, using minute fractions of the line to create a bitmap that could be used to mathematically describe and italicize metal type. Their system had unnecessarily great precision relative to the accuracy with which fonts could actually be cut. Further, it did not match the sizes of the fonts then in use. Fournier subsequently corrected these failings, using a larger point with greater compatibility with existing forms of type.