This project aids image analysis of archaeological ceramics by providing a series of digital images of ceramics of known recipe. The Laboratory-Prepared Specimens include red (E1, Earthen Red from Clay-King) and white (E2, White Earthenware from Clay-King) clays with sand (from Mile-Hi Ceramics, fine-grained, F, 70 mesh; medium-grained, M, 30 mesh; and coarse-grained, C, 16 mesh) added in varying amounts (10%, 25%, or 40% by volume of loose sand kneaded into wet clay). Surfaces of cut specimens were photographed under a stereomicroscope; and then thin sections (30 µm) prepared using a blue-dyed epoxy to attach specimens to glass slides. Five replicates of each combination of clay color, sand size, and sand percentage were scanned in a high-resolution film scanner (Plustek Opticfilm 7600i, optical resolution 3600 x 3600 ppi, 7 µm/pixel), making the entire thin section visible. Sand grains appear white and pores blue. Some were also photographed under low magnification (50x) in transmitted plane polarized light, with five fields of view for each thin section. Protocols for identifying area percentage of sand and pores were developed using Image-Pro Premier software by Media Cybernetics. Multiplying image analysis results for sand by 4/3 calibrates back to how a potter may have originally measured out a temper additive or determined a clay-aplastics recipe. Users can download images to replicate our protocols or develop new ones with other image analysis software. Archaeological Specimens includes ceramics analyzed by our protocols, with the results.
A full discussion of our protocols for image analysis of pores in ceramic thin sections is found in: Reedy, C. L., Anderson, J. & Reedy, T. J. 2014. Quantitative porosity studies of archaeological ceramics by petrographic image analysis. In: P. Vandiver, W. Li, C. Maines, & P. Sciau, eds. Materials Issues in Art and Archaeology X. Cambridge: Cambridge University Press, doi# 10.1557/opl.2014.711 (2014).
This work was supported by National Science Foundation grant 1005992.
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