Synergetic Interaction of Writing Materials

When studying the evolution of books from ancient times until the present, it is important to be aware of the simultaneous development of not only the text and its meaning, but also the different techniques and materials used through the ages. From approximately the 3rd century AC until the end of the Medieval Ages, when printing on paper was first introduced, manuscripts, scrolls, and book covers were manufactured using parchment, a material derived from animal skin, primarily sheep, calf, or goat. The main constituent of parchment is collagen, a protein with a triple-helix structure. Depending on the environmental conditions under which the medieval manuscripts are presented or stored (e.g., temperature, relative humidity, acidifying gases in the ambient atmosphere, and light), and depending on the composition of inks and pigments applied in the text and for the colorful miniatures (also called illuminations), collagen can undergo several degradation phenomena. These processes weaken the parchment structure, rendering it fragile and brittle. Moreover, they can induce a dark brown discoloration of the pigmented area, followed by mechanical damage (cracks), and, finally, loss of material (formation of holes). To study these phenomena, mock-ups of parchment, inks, and the combination of the two, will be prepared solely by following medieval recipes and procedures, using traditional materials (e.g. natural oak galls for the inks), to simulate original objects as closely as possible. In this way, it will be possible to reproduce medieval manuscripts, undergoing laboratory- controlled accelerated aging to simulate the effect of time on the objects and therefore their deterioration pathways. This will allow not only the identification of the deterioration factors but also to reconstruct the causes and chemical processes occurring during the aging. The combination of non- invasive analyses performed by compound-specific analytical methods such as Fourier Transform Infrared (FTIR) and Raman spectroscopy, as well as micro-invasive high sensitivity techniques such as Electron Paramagnetic Resonance (EPR) spectroscopy, are powerful tools for the investigation of deterioration processes occurring in proteinaceous materials. This strategy will allow not only to gain information about the deterioration phenomena found on the surface of the material but will also enhance the understanding of the chemical (deterioration) processes occurring deeper within the material. Following this approach, the complementarity of the information obtained will help to detect and identify the most relevant aging phenomena. It will therefore contribute to a more precise evaluation of the deterioration status of an object, to ensure a more effective and precise conservation strategy.

The research carried out within the project focused on the investigation of historical parchment manuscripts and their ageing processes. Many parchment objects preserved in archives and libraries are threatened by environmental influences, light exposure, air pollution, and natural ageing. The aim of the project was to better understand how parchment changes over time and how such alterations can be detected at an early stage in order to support improved conservation strategies. A central aspect of the work was the application of modern scientific analytical methods to historical materials. Both historical parchment fragments and specially prepared mock-up samples were investigated. Artificial ageing experiments under controlled conditions made it possible to simulate processes that would normally occur over decades or centuries. This enabled a better understanding of how environmental factors influence the structure and stability of parchment. Particular emphasis was placed on the use of Electron Paramagnetic Resonance spectroscopy (EPR), an innovative technique for the study of cultural heritage materials. This method makes it possible to detect very small chemical changes and degradation processes while causing minimal damage to sensitive historical objects. The analyses provided new insights into the chemical structure and degradation behaviour of iron gall inks, especially in interaction with proteinaceous supports such as parchment. By studying inks and support materials together, the project contributed to a better understanding of the complex relationship between writing materials and substrate during ageing. The novelty of the project was not only the introduction of advanced analytical techniques into this field of research, but also the systematic and interdisciplinary approach adopted throughout the study. Different complementary analytical methods were combined in order to obtain a broader understanding of the materials and their degradation behaviour. The integration of several techniques improved the interpretation and reliability of the results. The project also contributed to the development and optimization of analytical protocols for collagen-based materials and demonstrated the potential of EPR as a valuable tool for heritage science and conservation research. The results showed that environmental stress factors such as temperature, humidity, ultraviolet radiation, and atmospheric pollutants can significantly influence the chemical stability of parchment. Differences between naturally aged historical samples and artificially aged mock-ups were identified, improving the understanding of degradation pathways and the evaluation of laboratory ageing procedures. The project results contribute to the preservation of written cultural heritage by supporting conservators, archives, and libraries in assessing risks and developing suitable storage and conservation strategies. The findings were disseminated through scientific publications and presentations at international conferences and strengthen interdisciplinary collaboration between conservation, chemistry, physics, and materials science.