MCI Project Summaries 2008 - Smithsonian Institution

MCI 6039.2 Technical Study of the Remains of Painted Organic Objects from the
site of El Perú-Waka′, Petén, Guatemala
MCI Staff: Harriet (Rae) F. Beaubien, Colleen Snyder, Judy Watson, Lynn B. Brostoff, Mel J.
Wachowiak, Fabien Pottier
While objects made of painted wood, gourd and other organic materials were assumed to
have been produced and used in ancient Mesoamerica, information about them has largely relied
on much later ethnohistorical records dating from the time of European contact and beyond.
Archaeologically, these types of objects are rather rare, with find spots almost exclusively in
burials where the deposits have been relatively undisturbed. The substrate materials are
presumed to have been organic materials because of the totality of their degradation, a condition
not surprising in a subtropical environment. When found, these objects survive only as
concentrations of paint flakes.
MCI conservation assistance with lifting several painted organic objects from a burial at
the ancient Maya site of El Perú-Waka′ (Petén, Guatemala) led to a technical study at MCI of
selected paint flakes from these objects, along with three others from a second burial. Optical
microscopy, SEM-EDS and XRD analyses were carried out on small whole flakes, small
samples mounted in cross-section, and scrapings of color to investigate the composition of the
various paints, the paint application process, and texture on the back sides that might provide
evidence of the disintegrated organic substrate.
Analyses showed the use of stucco (lime plaster composed of calcium carbonate) as the
basis for the preparation layer and pigmented paints. Colors included cinnabar (mercuric sulfide)
and to a much lesser extent hematite (iron oxide) for reds, malachite (basic copper carbonate) for
green, goethite (iron oxy-hydroxide) for yellow and Maya blue (a lake pigment composed of
indigo and palygorskite clay); bone black or charcoal was used for black outlines. A variety of
ground or preparation layer types were identified, including white, cream, orange-ish and brown,
in both smooth and coarse textures. Some of the ground layer variation may reflect qualities
suitable for particular organic substrates, as well as differences in texture found in a single type
of substrate, such as the inner and outer surfaces of a gourd.
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