Application of reflectance transformation imaging to archaeological ceramics from the lower Paraná River (Argentina)

The aim of this paper is to advance the understanding of the technological processes behind pre-Hispanic ceramic production in the Lower Paraná River (Argentina) through the application of Reflectance Transformation Imaging (RTI). This computational stereo-photometric method allows the surface relief of objects to be recorded under different illumination directions. In this way, details such as cracks, changes in relief and small holes that are not visible by direct observation or standard photography can be revealed. This technique was applied to two ceramic objects recovered from the archaeological sites Cerro de las Pajas Blancas 1 and La Calavera (San Jerónimo department, Santa Fe province). From the first site, a motif made using the drag and jab technique was analyzed, and from the second site, a piece exhibiting a net imprint on its interior was studied. It is proposed, on the one hand, that RTI provides more information than standard digital photography for the documentation and analysis of different techniques applied to ceramic surfaces. On the other hand, RTI continues to demonstrate its value as a tool for studying archaeological artefacts, as it is effective, non-invasive, cost-efficient, and creates a permanent interactive record without the need for physical manipulation of the artefact.