Anne Turner Gunnison, Helene Tello, Peter Bolz, and Nancy Fonicello
Abstract
The North American collections at the Ethnological Museum in Berlin, Germany include a selection of 18 painted bison and cattle hide robes. Within this collection are seven rare and early examples of bison robes, collected in the 1830s by Prince Maximilian zu Wied on his travels along the Upper Missouri River. Due to their size, the robes present a challenge for the museum to store, exhibit, document, examine, and conserve. For almost 20 years, 14 of the robes were inappropriately stored, hung from trouser hangers clamped along their edges, in a case with limited access. This method of storage made it difficult to examine the objects for ethnological and conservation research.
An extensive preventive conservation project was undertaken to re-house the robes horizontally on trays, in a purpose-built storage unit. The robes were documented and condition checked. The project also incorporated an indepth study of a Piegan (Blackfoot) robe collected by Prince Maximilian. This study included identifying the dyes and pigments used in the quillwork and painted iconography, using high performance liquid chromatography and Fourier transform infrared spectroscopy. Experiments in dyeing quills with native dye material and using these dyes as paint on tanned bison hide were also undertaken.
As pesticide contamination is a prevalent problem in the Ethnological Museum collections, it was decided to identify and quantify the possible chemicals, including chlorine containing compounds like dichloro-diphenyltrichloroethane, lindane or polychlorocamphene, and heavy metal compounds like mercury(II)-chloride or arsenic trioxide, used on this robe, as well as two others, using gas chromatography-mass spectrometry and inductively coupled plasma mass spectrometry. Mercury was found at extremely high levels; this will present enormous problems when these objects are handled and studied. Current and future work must be carried out under strict protocol, including the use of suitable personal protective clothing.