Digital Lunch Seminar: Zooming In on Parchment Decay

The Kairouan Manuscript Project at CSMC: Zooming In on Parchment Decay

Salt, humidity fluctuations and microorganisms: a study on the degradation of the parchment manuscripts from Kairouan

R. B. Davidson MacLaren, Claudia Colini, Agnes Weiß

Written artefacts made from parchment are an important part of our cultural heritage. Since the collagen structure of parchment can deteriorate under various conditions, 'especially environmental conditions aggravated by climate change, the preservation of these historically and culturally valuable documents has become a major challenge. In addition to environmental conditions, the influence of microorganisms is another important cause of deterioration. To better counteract decay, it is important to gain an extensive understanding of its reasons and the microbiota of parchment. To date, multidisciplinary studies combining analytical and microbiological analyses are very few.

The present study was conducted within the framework of the Kairouan Manuscript Project (KMP), an international cooperation project between the Centre for the Study of Manuscript Cultures (CSMC) at the University of Hamburg and Tunisia’s National Heritage Institute (NHI). This project is dedicated to facilitating and advancing the care, management, study, and promotion of the collection of manuscripts held by the National Laboratory for the Preservation and Conservation of Parchment and Manuscripts (NLPCPM) in Raqqada, Kairouan, Tunisia, a division of the NHI. This collection, which was assembled from Kairouan’s teaching mosques and other religious institutions, is one of the largest collections of Islamic manuscripts in North Africa – and one of the most historically and intellectually significant anywhere in the world, especially for manuscripts dating to the 10th century CE or earlier. It contains an especially large number of parchment manuscripts, some of which are affected by an unusual and aggressive form of deterioration. In November 2024, a delegation from the NHI brought 15 parchment fragments to Hamburg for a period of two-weeks to undergo analysis at the CSMC by members of the Mobile Lab and the Hamburg School of Food Science. The investigations aimed at characterizing visually intact as well as deteriorated areas of the parchment fragments with a focus on substances and microorganisms that might be involved in the decay. Special emphasis was placed on using non-invasive methods. The talk will introduce the KMP and its mission and will give an overview of the analytical techniques used, in particular Multispectral Imaging (MSI), 3D Microscopy, X-Ray Fluorescence (XRF), Scanning Electron Microscopy (SEM) and microbiological analysis. It will highlight the main findings, describe the differences between intact and decayed areas, propose preservation measures, and identify directions for further research.

R. B. Davidson MacLaren is research associate for cultural heritage and coordinator of international cooperation at the CSMC. He is also a member of the Kairouan Manuscript Project leadership team. He has a background in collection care and management, especially the cataloguing, conservation, and exhibition of Islamic manuscripts; provenance research and the investigation of heritage crime; and book history and Islamic studies.

Claudia Colini is Junior Professor for Archaeometry at the Institute for Archaeology and Cultural History of the Ancient Mediterranean, University of Hamburg and Head of the Mobile Lab of UWA and CSMC. She has a background in archaeometry and book conservation, in particular of Islamic manuscripts and their materials. Her current research projects focus on the coexistence of different writing supports, inks and colours in the early centuries of Islamic Egypt.

Agnes Weiß is professor for Food Microbiology at the Hamburg School of Food Science, University of Hamburg, and member of UWA. Her main research interests are microbial communities, the interactions between microorganisms and food commodities as well as the impact of food commodities on the microbial metabolism. This also includes novel preservation technologies, clean-label products and sustainable fermentation strategies. Within UWA she is interested in which microorganisms might cause parchment decay, how decay can be monitored as early as possible and which environmental factors enhance decay.