Through a laser beam darkly—attempting a reassessment using optical diagnostics in epigraphy

In 1990, the late ancient historian Mortimer Chambers conducted a study in which a laser beam was used to make a worn inscription visible by shining it through a 19 cm-thick marble block from behind. The study on the Egesta decree (IG I 3 11) was quickly criticised: ‘Through a laser beam darkly.’ To replicate and contextualise Chambers’ observations, this study first examines a 4th-century AD epitaph in a laboratory setting using modern optical and non-destructive testing methods, and then apply the most practical methods to the decree at the Epigraphic Museum in Athens. The workflow combines reflectance transformation imaging, ultraviolet fluorescence, near-infrared reflectography and transmission, and active thermography to clarify a long-standing debate in epigraphy methodology. This study demonstrates that easy-to-use, cost-effective IR/UV tools can deliver interpretable results for analysing the Egesta decree.