Since the 18th century it has been noticed that not all individual
impressions of Gutenberg's types are exactly identical. No comprehensive
attempt had been made to explain this until very recently. An American
physicist working with a bibliographer has undertaken a cluster
analysis of digital images of individual impressions of a letters.
They have concluded that Gutenberg's method was not the one which
was in use at the end of the 15th century. This is a good illustration
of how Gutenberg's invention of printing was the beginning of a
process of refinement and improvements.
By the 1470s type was produced in way which remained unchanged
for centuries. A letter was engraved onto a punch of hard metal.
The punch was hammered into a softer metal, creating a matrix. The
matrix was fitted into a mould and a piece of type was made by pouring
in a lead and tin alloy. A type founder could thus produce hundreds
of pieces of type, each with identical mirror images of the same
letter or sign.
A printer would have many pieces of type for each letter, all leaving
the same impression on the paper. They could be put together to
form words, sentences, and pages. When enough copies of a page had
been printed, the types could then be taken apart and used again
to form new words, sentences and pages.
This proved one of the great advantages of printing. Otherwise
it would not have been possible to produce many copies of the same
text with speed and economy. In the 1470s an Italian bishop explained
that three printers working for three months could produce 300 copies
of a book. He estimated that it would have taken three scribes a
lifetime each to complete the same number.
The type used by Gutenberg resembles a formal type of contemporary
handwriting known as textura, because its strong vertical
and horizontal lines gives the impression of the texture of a woven
pattern across the page.
It measures 146 or 147 mm per 20 lines on the pages that have
40 lines to the page.
It was filed down to measure 138-140 mm per 20 lines on the pages
that have 42 lines per page.
The typed area of the pages that have 40 lines per page measures
294 by 198 mm.
The typed area of the pages that have 42 lines per page measure
292 by 198 mm.
The typed area of the single page (fol. 310 recto) which has 41
lines measures 284 by 195 mm.
A resource on type-making has been made for the Huntington
Paul Needham and Blaise Agüera y Arcas have examined how Gutenberg
made his type, in
Blaise Agüera y Arcas, 'Temporary Matrices and Elemental Punches
in Gutenberg's DK type' in Incunabula and Their Readers: Printing,
Selling and Using Books in the Fifteenth Century, edited by
Kristian Jensen (London: The British Library, 2003), pp. 1-12. ISBN