Comparing the "Gutenberg Bible" with Digital Images: New Research Techniques Lead to New Discoveries

In the mid-15th century, the first book in the world was printed using movable type: the "Gutenberg Bible." Of the approximately 200 copies printed, only 48 remain in the world, including incomplete ones. No two books are exactly alike, as corrections were made during the printing process. Keio University acquired one of these precious copies in 1996, and the HUMI Project, launched at that time, has been digitizing it.

My specialty is bibliography, and I use these digital images to study the printing techniques, layout, and other aspects of the "Gutenberg Bible." Gutenberg's printing technology spread rapidly and had a major impact on the world. It is considered one of the three great inventions of the Middle Ages, along with gunpowder and the compass, yet no records of it remain. Many things are unknown, such as the backgrounds and number of craftsmen involved, the procedures they followed for printing, and how errors were corrected.

Comparing copies of the "Gutenberg Bible" from around the world provides clues to solving these mysteries. For example, the corrected sections reveal certain things. The craftsmen worked in teams using multiple printing presses, and when an error was found, they would stop the press to make corrections. We can see that while one group of craftsmen focused mainly on design-related corrections, another group meticulously corrected everything, even spelling mistakes in Latin. Through repeated comparisons like these, we can infer the details of the work process.

Research on the "Gutenberg Bible" has a long history and is conducted worldwide. One might think that the topic has already been exhaustively studied. However, even with old research themes, new discoveries can emerge when new research methods and technologies are developed. The "Gutenberg Bible" is a first-class rare book, so the original copies are strictly protected and not easily accessible. But once digitized and made available on the web, anyone can study them freely from anywhere. In fact, by calling up and overlaying digital images of the same page from the Keio University and Cambridge University copies on a computer, one can make accurate comparisons in a short amount of time. It is fascinating how technology can elevate research in this way.

Currently, entire pages are digitized as images. If technology advances to the point where computers can automatically convert each individual character into data, it will become much easier to compare texts and identify trends in corrections. I anticipate that this will lead to another leap forward in research.