X-ray fluorescence investigations of ancient Greek and Latin epigraphs

Abstract

Many ancient Greek and Latin epigraphs, once clear text on limestone and marble, have weathered and worn over the course of many centuries so that the words written on them are no longer legible. X-ray fluorescence, a common nondestructive chemical analysis technique, is extended to synchrotron-based X-ray fluorescence imaging, with which we can map the relative concentrations of many elements near the surface of a stone epigraph. We investigate the application of X-ray fluorescence imaging to these epigraphs.

Initial results show an association between fluorescence intensity from trace elements near the surface of an epigraph and the presence of a glyph carved in the stone. Further, it is demonstrated that mapping this fluorescence intensity can, in some cases, improve legibility of the text beyond the capabilities of the unaided eye. Further investigations explore in more detail the usefulness of different trace elements for imaging text, potential origins of these trace elements, fluorescence intensity effects associated with the physical topography of the stone, and the application of statistical analysis techniques to X-ray fluorescence imaging data. We also apply our methods to an epigraph of uncertain provenance, demonstrating that the evidence provided by X-ray fluorescence indicates that it is a modern copy of another epigraph.