Multi-analytical study of shaping firing and painted inscriptions in a Roman Titulus Pictus amphora

During the Roman period, amphorae were essential for storing and transporting goods, especially food. This study examines a fragment of a Roman amphora with a red titulus pictus, discovered at the Poggio Moscini archaeological site (Bolsena, Italy) and dated between 150 and 100 BC. A comprehensive archaeometric study has been conducted using the non-disruptive techniques of X-ray microscopy (XRM), X-ray powder diffraction (XRPD), energy-dispersive X-ray fluorescence (ED-XRF) spectroscopy, fiber optics reflectance spectroscopy (FORS) and micro-Raman spectroscopy. XRM revealed a preferential pore orientation consistent with wheel-throwing manufacture. XRPD identified quartz, diopside, gehlenite, anorthite and sanidine, indicating the use of Ca-rich clays and firing temperatures between ~900 and 1000 °C. ED-XRF demonstrated a similar composition between the ceramic body and the pigment, confirming Fe-rich clay and Fe-oxide-based pigmentation. FORS shows absorption features typical of hematite, and micro-Raman spectroscopy identifies hematite as the red pigment and rules out gypsum in the ceramic body.