Typography: the "Smoking Gun" (or "Grooved Bullet") of Hand-Press Books
Just as the study of paper, including watermarks (Stevenson), reveals historical evidence about when a paper document originated, and the style of a scribe's manuscript hand can suggest when the document was created, study of the type fonts used to create printed books reveals very specific forensic evidence about the printer who produced it. Early printers made their own fonts by hand-cutting the dies which produced each piece of type, or commissioned them individually from the first specialist type founders. Printers' heirs inherited their type fonts, as well (e.g., Wynkyn de Worde uses Caxton fonts). The study of printing fonts, like the study of firing pin marks and rifling grooves on a bullet, can enable us to trace the printed object back to the pieces of type which created it. Any hand-press book's letters bear the distinctive imprint of its type font at the moment in history when that font was in that state of repair, identifying not only the printer, but also the year in which it was printed. "Dings" in clipped, broken or bent letter forms reveal the gradual wearing of individual pieces of type in a font, allowing scholars to date undated books by comparison with dated books that preceded or followed their contact with their font of type.
Gothic and Roman Type Examples : This list of images represents a fairly large sample of the GmT survey of incunable type fonts in Gothic and Roman type used in Europe and England up to 1501. (The National Diet Library, Japan).
Haebler's "M" Type List for European Incunabula Printers: Just a big page of "M"s, but note how distinctively different they are! Each one identifies a different font of type operated by a different printer. Haebler's genius was in realizing that from just one letter from each font one could identify the source for all the rest of that font's alphabet. The logical principle is sometimes called "ex pede Herculem" (from the foot of Hercules [one can know the man]. When you have identified your fount's capital "M" in Haebler's list, use its number with the GfT lists on the page linked below to determine which printer used the fount. (The National Diet Library, Japan).
The Gesellschaft für Typenkunde des 15. Jahrhunderts (AKA "GfT"): A 1-page description of a German typography project to identify all European fonts, producing tables and lists of printers linked to images of their fonts (see tables below) and to Haebler "M" types. The Collection of Images of GfT Founts linked at the bottom Gothiof the page is a particularly useful resource, with online images of 110 Gothic and 50 Roman type fonts grouped by region and city (The National Diet Library, Japan).