ABC – Ancient Book Crafts

Old books are venerable witnesses of our culture. They seem sublime, almost magical. But what makes an old book an old book? It is the handwritten texts, the scent of parchment, the crackling of old papers, the crunching of the artistically decorated leather bindings: each book is unique and precious. It is not the familiar title page, invented only in modern times, that reveals the age. In the centuries before, dates were given rather arbitrarily. This sometimes raises doubts as to whether the information is reliable. There is also the question of whether the book was written in one piece, whether the binding is still original or whether it has been rebound. The question of the age of a book can therefore only be answered by bringing together various aspects that concern content and materiality in equal measure. Our project is trying to develop a tool by applying both natural science and humanities methods to be able to reliably date unknown or questionable objects. On the natural science side, the chemical structure of the material of ancient cultural treasures is determined non-destructively with the help of infrared light (IR) - IR spectroscopy. For this, the device does not even have to touch the book. As the material ages, it changes, and we use this change to create a model that can be used to estimate the age of a material. To create the model, we need a set of books for which the age is undoubted. This is where the humanities methods come in, based on the evaluation of relevant entries in the books, historical binding techniques and tools. The Library of the Augustinian Canons in Klosterneuburg, as one of the largest collections of medieval books in Austria, offers the ideal resources for this. To check whether our model also works with books in other libraries, the project is coupled with a sister project in Slovenia. There, a set of books is compiled in the National Library of Ljubljana and measured using IR spectroscopy. However, the equipment is slightly different from that of the Klosterneuburg team. The devices will therefore be exchanged so that both devices measure both sets of books. Finally, we will also carry out measurements at the National Library in Prague in order to put the finishing touches to our models. At the end of the project, we want to make these models available to the public so that they can be used in many other libraries, archives, and museums in the future. The non-contact measurement also makes it possible to research sensitive objects that cannot be processed with many other methods. In this way, completely new research questions can also be answered and perhaps even the history of some books will be completely rewritten.

Age is one of the most important data about historical objects. Dating of books can be done by means of codicology using information written in the text, datable watermarks on paper, or stamps on the leather cover. Molecular changes of the material itself can support the results in a complementary way. For that purpose dating models must be established that calibrate the molecular pattern with codicological results. The ABC Project (Ancient Book Crafts) successfully applied Fourier Transform Infrared Spectroscopy to identify chemical bonds that contribute to decay in medieval leather materials. Using these chemical structures and dates gathered through studying parts of the book structures we were able to build a model that can predict the age of manuscripts/ incunabula and bindings in Klosterneuburg. Incunabula are the earliest objects printed with moveable types from the second half of the 15th century. Infrared spectroscopy works by giving enough energy to the chemical bonds that they are over excited and need to release excess energy which is picked up by a series of detectors inside the Infrared Spectrometer. Out of this a spectrum can be calculated that is for the material specific like a fingerprint. The characteristic spectral peaks of leather are known. Using these known bonds we can establish and interpret a specific spectrum for each manuscript. As these bonds get older there are subtle changes in the chemical signature that is possible to see. This monotonous rate of change, or decay rate, can be monitored through machine learning algorithms and a model created. We use this model to predict the ages within +/- 65 years, where before the only way to predict the age involved removing pieces of the manuscript - a procedure very often not acceptable for the highly valuable objects. As part of these investigations, 450 manuscripts and incunabula were codicologically examined for their bindings and the period-specific materials and techniques used. All blind-stamp motifs were recorded and digitized; those with secured provenience from the Klosterneuburg bookbindery, which was active for several centuries, were added to the bookbinding database EBDB. In this way, codices produced elsewhere could also be identified (purchases were primarily from southern Germany and Venice). Furthermore, the activity of the Klosterneuburg bookbinders was historically substantiated by archival evidence, particularly account books that recorded the purchase of fittings, casting molds, and leather. The dates obtained from the codicological analysis formed the basis for the calibration of the measuring device and were also added to EBDB (currently under review).