In the Herzog August Bibliothek Wolfenbüttel all books intended for digitization are first assessed in terms of their physical condition, opening characteristics, and the particularly intensive mechanical stress and its impact on being handled during the conversion process. In the case of the digitization project Manuscripts from German-Speaking Lands – Handschriften aus dem deutschen Sprachraum, funded by The Polonsky Foundation, the results of this preliminary assessment indicate that about half of the selected manuscripts require conservation measures before the actual digitization can begin.
This is hardly surprising considering these books have been in use for centuries. First in monasteries for intensive study, edifying purposes and pious contemplation; and in more recent years as objects of research for scholars and scientists. Readers have not always handled the manuscripts with care, while materials such as parchment, paper and leather become brittle and stiff due to natural aging mechanisms and unfavorable storage conditions in unheated, damp rooms. Furthermore, mold or insect damage might have additionally harmed them.
Many manuscripts show their eventful history and frequent use: pages are soiled, creased, and torn, or sometimes torn out entirely. The covering material is rubbed, torn or has come loose; the aged, stiff leather joint burst open and the protective wooden boards are not infrequently broken or the clasps almost torn off.
The fragile, damaged books are therefore prepared in the conservation laboratory with small but effective measures to enable digitization. Once digitized, not only do researchers benefit from the existence of a high-quality digital copy: sensitive manuscripts themselves can be used less often, aiding in their protection.
However, by no means all damage is treated. For all interventions this stipulation applies: as much as necessary and as little as possible. This extremely cautious approach is intended to change the book as a historical object of use as little as possible in order to leave material aspects legible for research. Nevertheless, the risk of damage during use - and this includes digitization - should be minimized. For example, in the case of the frequently-encountered tears of pages, these are mended only if the tears extend into the leaf to the point that they might tear further when turning the pages.
As a preventive, non-invasive measure that does not require direct intervention, a simple dust wrapper is often made of archival paper. It protects the sensitive leather cover or already-torn but still sufficiently stable joints from mechanical stress on the surface of the copy stand, but is easy to remove when capturing bindings and edges. A transparent wrapper material was chosen in one particular case: The leather cover of a manuscript from the Augustinian convent of St Marienberg in Helmstedt (Cod. Guelf. 506 Helmst.) was completely torn at the left joint. It had originally been adhered directly to the spine of the book, but had come loose over time and now reveals an unobstructed view of the extremely solid sewing structure of the 14th century. Instead of reconnecting the torn leather by conservation measures, a protective wrapper was made from a transparent, thin polyester film. The reversible construction protects the sensitive, damaged areas, while at the same time the otherwise concealed archaeological information on the spine, sewing, sewing supports, etc. remains accessible for research.
In many cases, the focus is on re-establishing the mechanical properties of damaged materials during the opening movement. The outer joint of a hymnal also from St Marienberg (Cod. Guelf. 501 Helmst., 14th–15th century) was torn and parts of the leather on the spine had come loose to such an extent that it was in danger of being lost. Filling of loss by inserting several layers of dyed Japanese paper connects the joint so that the book can now be opened without danger of further damage. The long-fiber Japanese paper is ideal for use in joints thanks to both its stability and flexibility. It enables hinging movements without stressing the sensitive original leather cover or creating tension in the material compound.
Clasps made of copper alloy similarly entail mobility: When opening and closing wooden board bindings leather straps to which clasp hooks are attached function as hinges. Due to mechanical stress on the aged, brittle leather these straps are often torn or even completely detached and lost in the course of time. To secure and reconstruct the function of the leather strap of a small-format, Low German prayer book from the 15th century from St Marienberg (Cod. Guelf. 1307 Helmst.) a suitably prepared piece of vellum is inserted between the leather layers and the tear is additionally secured with Japanese paper in order to sufficiently stabilize this mechanically highly stressed area.
In its uniqueness, each manuscript requires subtle approaches to assessing the limits of the resilience of its fragile, aged materials. It represents an evaluation of the possibilities and individually adapted decisions as to which techniques and measures are best suited. With all conservation steps carried out, the materials and adhesives used are documented both in written form and photographically before the books start their grand performance in the photo studio and then become visible to the interested public in digital format on the project’s website.
About the authors
Marenlise Jonah Hölscher and Katharina Mähler work in the Department of Collection Care and Conservation at the Herzog August Bibliothek and have supervised and accompanied the digitization of the manuscripts in the project.