UCLA

Paramount in the study of Andean civilizations, past and present, are the rituals and ceremonial customs practiced through the Inka and post-Inka periods. Decorated wooden cups called qeros have facilitated these customs through the centuries, experiencing long use-lives as they are passed down from generation to generation, holding libations to the gods in rituals and celebrations that ensure the community’s prosperity and good health. It is from here that qeros enter museum and private collections, their use-life ends, and their preservation as vestiges of Andean culture begins. Decorated by brilliantly colored organic inlay, commonly known as mopa mopa, there is currently a lack of information concerning dark material that often surrounds the mopa mopa polychromy. This dark “background” at times exhibits peculiar and substantial loss on qeros in many collections, sometimes as though it has been purposely scraped off. For this study, dark materials on a group of qeros belonging to the Fowler Museum at the University of California-Los Angeles were investigated in an effort to characterize them and potentially explain their presence and causes for loss. Several documentation and analytical techniques were employed, including visual analysis, digital photography, UV-induced visible fluorescence, Reflectance Transformation Imaging (RTI), portable X-ray Fluorescence (pXRF) spectroscopy, Fourier Transform Infrared (FTIR) spectroscopy, and Gas Chromatography-Mass Spectrometry (GC/MS). Results showed this dark material to be a mixture of organic components—fatty acids, oils, and possible natural resins—most likely deposited on the surface from the cups’ ethnographic use. A couple instances of dark inlay decoration were found to be a chemically similar material, and another similar oil-based mixture was found to be used as a type of surface application. Obvious tool marks targeting the removal of the dark material suggest there were mechanical interventions meant to clean the cups of dark ethnographic accretions so that their polychrome imagery showed unobscured. Identifying these materials, understanding their origin and explaining their loss, contributes to our knowledge of qero history and guides our custodianship over these artifacts of Andean traditions.