Reading ceramic surfaces: Characterisation of surface treatments towards functional identification of vases

Abstract

This study explores the characterisation of clay vases surfaces through tribological analysis and more precisely the relationship between surface treatments and watertightness. Different surface treatments were tested (pre-firing: smoothing with a wet hand, a wooden tool, a piece of cloth, burnishing using a pebble and a combination of a pebble and a piece of leather; and post-firing organic coatings: milk and fleece on red hot surfaces and olive and beeswax applied to the room temperature clay tablets). Surfaces were measured and characterised using a confocal rugosimeter, as well as the method of continuous wavelet transform. These multiscale analyses allowed the classification of surface treatments into four morphological groups. Furthermore, water and oil drop deposition tests allowed the characterisation of a surface’s reaction when exposed to liquid contents. These results have implications in evaluating storage and cooking performances and specific uses of clay vases in relation with organic materials. The discussion will also provide insights regarding the importance of the first use of a pottery in the chaîne opératoire of manufacture.