Using computer software, Blaise Aguera y Arcas and Paul Needham analysed Gutenberg's work to try and identify the tools he used to create them. To their surprise, they discovered every letter was different, casting doubts on his methods.
Paul and Blaise started their research with work done in the 1960s by Charlton Hinman.
He completed a comprehensive analysis of Shakespeare's First Folio, comparing the differences in type setting between different copies, including the identification of broken and damaged types.
He was able to determine the sequence of printing, of corrections that were made in press, and re-settings. This gave an insight into the way in which Shakespeare wrote his plays and the order in which they were amended. Hinman used a device based on a machine for analysing aerial photographs from the Second World War.
Gradually, Paul and Blaise came to realise that, rather than developing a method of dating books, they had unearthed a fundamental flaw in our assumptions about Gutenberg's printing methods.
Doubts about what Gutenberg invented had been expressed before. Among the sceptics was Fournier Le Jeune, a printer and type founder in the 18th century, who examined some early Gutenberg printing and concluded that it wasn't printed from type cast with a reusable matrix.
He'd noticed irregularities and believed that the documents were printed from wooden types that were carved individually. That has since been disproved.
Using digital photography and computer software Blaise and Paul analysed Gutenberg's work to try to identify the tools he used to create them. They superimposed the same letters to see whether they were identical and therefore made with the same punch.
To their surprise each letter in its many reproductions on each page varied, even though they could find identical repetitions of that letter on other pages.
For months Blaise honed the software package to try and explain the variations in printed letters that were identified. The discovery wasn't a bolt from the blue but what Blaise describes as "subtle Eureka moments".
One of them was in the comparison of the hyphens in Gutenberg's Bible where it was most obvious that the variations couldn't have come from wear and damage on the pieces of metal on the types themselves.
The variations were great enough not to be explained away through different amounts of ink on the type. They concluded that the type couldn't have been produced with a punch and matrix.
Focusing on individual letters they discovered overlaps in the ink, which again raised questions about the methods we've assumed for centuries.
The history of technology only makes sense if we understand the context in which new technologies developed.
The imaginative genius of the inventor is only realised through the skills of the workforce; the demand for the invention, and so its widespread adoption, depends on the priorities of the society. We need to look at the investors and the purchasers as well as the inventors if we are going to understand technological change. If you are interested in studying the relationship between technology and society you can find it discussed in A103 An Introduction to the Humanities and in AS208 The Rise of Scientific Europe. For those with some experience of academic study, the third level course AA305 The Renaissance: A Cultural Enquiry considers the contribution of printing to Renaissance scholarship. AT308 Cities and Technology: from Babylon to Singapore is a broad survey course concentrating on the relationship between technology and the growth of cities, with a section on Renaissance urban planning.