Museum De Lakenhal has a rich history in textiles, as it used to function as a quality inspection hall for cloth during the 17th and 18th centuries. From this period, 33 sample books (1690 – 1791) still remain in the collection. These books were used to keep track of the dyeing quality of black woven woollen fabrics. Each volume includes two rows of approved fabric samples adhered with sealing wax and accompanied by information such as the name of the dyer, the dyeing quality of the fabric, and the date of inspection.
The main issue facing these sample books in this collection is a strong deformation of the book block. Each page has a distinct wave-pattern, and the level of this deformation tends to vary per volume. Even within the volumes themselves, each page has its own wave style. This makes these books almost difficult to open without inflicting further damage upon them. The fabric samples that sit alongside the information add to the complexity of studying these volumes, as they risk being ripped from the page when flicking through the book.
The complexity of handling these objects made research about them difficult. It is therefore desirable to digitise the collection to increase accessibility and its value. Funded by Metamorfoze, Museum De Lakenhal started a research project to explore how the books can be safely digitised in their current, deformed condition. In this project, the Factum Foundation is involved in helping make the content of these volumes available through the application of non-contact digital technologies.
The Lakenhal sample books are very valuable, as both a research object for art historians, and for historians focusing on fabric manufacturing and trade (such as dyeing techniques, quality and information on the makers of these fabrics). The book collection spans almost 100 years, providing evidence of the alterations in production or quality.
Close-range photogrammetry recording of one of the volumes © Museum De Lakenhal
This complex and delicate digitisation task began in December 2022 with a photogrammetry test on a heavily distorted page. This test allowed for the assessment of the best methodology to virtually flatten the books in post-processing, making the text readable again. This initial test paved the way for the next steps in the collaboration. In July 2023, two of Factum Foundation's expert technicians conducted the scanning of a total of 15 pages from 8 different volumes in high resolution. They used both close-range photogrammetry and the Selene System. The results of these preliminary tests are promising and will help determine the specific method to be applied if the rest of the volumes are to be digitised.
The Selene Photometric Stereo System, developed by Jorge Cano and Factum’s engineering team, is demonstrated to be essential for a re-discovery of the information hidden in the near-planar surface of manuscripts. This project will contribute to defining historic books as three-dimensional, dynamic, material objects, recognising layers of meaning that coexist with the texts contained in them.
3D model showing a lateral view of one of the volumes © Factum Foundation for the Museum De Lakenhal