The study of boxwood prayer beads and miniature altars from the Thomson Collection at the Art Gallery of Ontario and the Metropolitan Museum of Art

Lisa Ellis, Pete Dandridge, Alexandra Suda, Barbara Drake Boehm, Elizabeth Moffatt, and Jennifer Poulin


The Thomson Collection of European Art at the Art Gallery of Ontario and the Metropolitan Museum of Art each holds an impressive number of early 16th century, miniature boxwood carvings known as prayer beads and miniature altars. These intricate objects have fascinated collectors and now museum visitors with their diminutive scale, intricacy and somewhat mysterious methods of construction. A technical research project exploring these objects is underway at the Art Gallery of Ontario and Metropolitan Museum of Art: findings will be shared in an exhibition at the Art Gallery of Ontario, Metropolitan Museum of Art, and the Rijksmuseum. The study of carving techniques and strategies of joining tiny, interlocking pieces will help group the objects into clusters of makers and/or workshops and perhaps even determine a chronology of manufacture.

Conservators and curators at the Art Gallery of Ontario and the Metropolitan Museum of Art have profited from different institutional collection strategies and staff expertise for the benefit of the project. The Art Gallery of Ontario’s investigation relies on micro-computed tomography (high-resolution X-ray tomography), a non-invasive tool which reveals the carvings’ internal structures and features. Imaging software allows 3D virtual models to be created from the high resolution X-radiographic scans which can then be examined and manipulated in a so-called “virtual deconstruction.” With the information provided by the micro CT scans of their objects, the Metropolitan Museum of Art took the additional step of deconstructing their boxwood objects to the extent possible. With greater access to their interiors, specifics of tooling and fabrication could be documented microscopically, intrusive restorations reduced, broken elements re-adhered, and accumulated dirt and insect casings reduced. The Art Gallery of Ontario has also embarked on an ambitious program to photograph the entire opus of prayer beads and miniature altars extant internationally (about 130 objects) using high resolution, focus stacking software. This will allow the comparison of objects and examination of detail impossible to date with the constraints of traditional photography, which was only able to produce hazy images of these tiny works.

To more thoroughly understand original manufacture and subsequent repairs and restorations, minute samples of the Art Gallery of Ontario’s works’ adhesives, coatings and polychromy are being analysed at the Canadian Conservation Institute with Fourier transform infrared spectroscopy; scanning electron microscopy-energy dispersive spectrometry; pyrolysis gas-chromatography-mass spectrometry; and with a Bruker Senterra dispersive Raman microscope. Similar analytical work is being undertaken at the Metropolitan Museum of Art. The employment of new technologies such as micro-computed tomography scanning, and focus stacking software along with the analytical work carried out at the Canadian Conservation Institute and the Metropolitan Museum of Art, is providing previously inconceivable access to the prayer beads and miniature altars. The resulting data, including high quality images and previously hidden construction details, will allow conservators to posit credible theories about makers and chronologies of manufacture. The collaboration between institutions is yielding greater results than would otherwise be possible: there is access to a greater number of works for research purposes as well as the benefit of a collegial environment in which to share findings and deliberate their meaning.