Fig. 4

a Photographic detail of the TP-IEP chalice, view form below; b Detail of the knop with the silver-gray alloy visible, as well as the blue glass; c Detail of the purple glass; d Detail of the red glass; e Comparison of the XRF spectra from the bowl alloy (bottom orange line) and base alloy (top black line). f Comparison of the XRF spectra from the knop gilding (bottom orange line) and base gilding (top black line); g Comparison of the XRF spectra from the transparent glass (top blue line), blue glass (middle black line) and purple glass (bottom orange line); h XRF spectrum of red glass. The inset display a zoom in of the same spectrum to highlight the elements detected at low peak intensities. Pb and Fe peaks in g and h were cut for highlighting traces elements in the region of interest