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Evaluating Visual Criteria for Identifying Carbon- and Iron-Based Pottery Paints from the Four Corners Region Using SEM-EDS
Published online by Cambridge University Press: 20 January 2017
Abstract
Paint types on black-on-white pottery in the prehistoric American Southwest have had significance for both chronological and sociocultural interpretations. Visual attributes have formed the basis for distinguishing carbon- and mineral-based paints on ancient black-on-white pottery in the American Southwest for over 60 years. In this study, an SEM-EDS (scanning electron microscope-energy dispersive X-ray spectrometer) system was first used to make an independent objective determination of the mineral or non-mineral paint present on 15 Mesa Verde White Ware sherds. Then, a group of 19 people (including experienced archaeologists and newly trained individuals) examined and classified the paint on these sherds, achieving an overall accuracy of 84.2 percent. This group also ranked in priority order the visual attributes they felt were most useful in determining pottery paint type: nature of edges (fuzzy, sharp), absorption (soaks in, sits on top), luster (shiny, dull), color range (black-gray-blue; black-brown-reddish), flakiness (doesn't flake off, flakes off), thickness (thin, thick), and surface polish (polish striations visible through paint, striations not visible through paint). In each case, the attribute applicable to carbon-based paint is listed first. The most difficult sherds for the group to identify displayed attributes of both carbon and mineral paints. A category for "mixed" paint type, already in use by archaeologists, is a reasonable third category for labeling sherd paint, as long as it does not become a "catch-all" category. For problematic sherds, the SEM-EDS can be used to characterize paint type, then the visual attributes adjusted to improve investigator accuracy in paint type determination.
Résumé
Los tipos de pintura utilizados en la cerámica prehistórica negro-sobre-blanco en el Suroeste norteamericano son significativos en interpretaciones cronológicas y socioculturales. Por más de 60 anós atributos visuales nan sido la base de la distinción entre pintura orádnica (o carbonácea) y mineral. En este estudio se utilizó un sistema de SEM-EDS (microscopio electrónico de barrido-espectrómetro de energía dispersiva rayos-x) para determinar objetiva e independientemente la presencia de pintura mineral o no-mineral en 15 tiestos de la vajilla blanca Mesa Verde. Luego, un groupo de 19 personas (incluyendo arqueólogicos profesionales y principiantes) examinaron y clasificaron la pintura en estos tiestos, obtieniendo una exactitudpromedio de 84.2 por ciento. Este grupo también clasificó en orden de prioridad los atributos visuales considerados más útiles para determinar el tipo de pintura cerámica: hordes de la pintura (precisos, vagos), absorcion (pobre, efectiva), brillo (brillante, opaco), rango de color (negro-gris-azul; negro-café-rojizo), desprendimiento (se desprende, no se desprende), grosor (fino, grueso), ypulido superficial (estriaciones visibles a través de la pintura, estriaciones invisibles a través de la pintura). En cada caso, el atributo applicable a la pintura orgánica se lista primero. Los casos más dificiles de indentificar son aquellos tiestos que exhiben atributos tanto de pintura orgánica como mineral. Una categoria de "pintura mixta," utilizada por arqueólogos, es razonable en tanto y cuanto no se convierta en categoría residual. Para tiestos problemáticos el SEM-EDS puede usarse para caracterizar el tipo de pintura y así afinar la identificación basada en atributos visuales.
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- Copyright © The Society for American Archaeology 1999
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