Lieve Watteeuw, KU Leuven, Faculty of Arts, Illuminare – Centre for the Study of Medieval Art and Cecilia Duminuco, MA student, West Dean College, Book Conservation Programme 2014-2015

Sewing threads in hand-made West European bookbinding: Historical sources, imaging and analytical assessment ( 12th -19th century)

Sewing threads are an essential part of the material make-up of a handmade European book, necessary to make a bound volume strong and durable. The thread is carefully purchased, selected and prepared by the bookbinder in regard to the thickness and softness of the paper or parchment and to the number of sections to be sewn. In the studies of historical bookbinding’s, the characteristics of the sewing threads are rather left aside, while the sewing structures are well studied and developed. The difficulty to evaluate this small textile items in the deep gathering folds is certainty an obstacle. This research aims to shed light in an multidisciplinary way on the typology and damages of historical sewing threads in hand made books.

The sewing threads research project focused on the assessment of a corpus of manuscripts and printed books from Western Europe, ranging from the 12th to the early 19th century. The study explores the history sources, the typology and incorporates an analytical assessment of sewing threads in hand bound Western Europe bookbinding structures. The corpus was selected in the collection of the Library of the Faculty of Theology at KU Leuven. The project involved expertise in bookbinding and in historical textile identification, with visual and analytical evaluation.

The paper will explore the raw materials and their characteristics of the threads, tools for making sewing threads, organization of the “thread makers” or spinners in medieval and early modern times, the sewing by the bookbinder (sewing by hand, sewing tables, the use of the thread, waxing, bookbinding processes in relation with the sewing thread (beating, gluing of the spine, etc. and types of sewing thread damages. To evaluate the corpus, a “sewing surveys” template was created to assess visually the sewing structures of the books ( an extension of the “Ligatus Project” database). Format, colour, texture, yarn, shape, imprint and condition of the sewing structures and of the threads were analysed and evaluated.

To measure and analyse in detail the texture, twining and twists of the treads, Reflectance Transformation Imaging (RTI) was then applied (RICH Project). For identification the fibres of the sewing threats ( flax, linen, hempen… ), small samples were taken and analysed by stereomicroscopy, by the use of reagents, by Micro Raman and by Scanning Electron Microscopy (SEM) in collaboration with the Institute of Cultural Heritage (KIK- IRPA) in Brussels.

This research (MA West Dean) was developed in collaboration with the Faculty of Arts, KU Leuven, the RICH project ( Reflecting Imaging for Cultural Heritage) and the Maurits Sabbe Library, Faculty of Theology of KU Leuven ( University of Leuven, Belgium).