Color attributes of medieval window panes:electron paramagnetic resonance and probe microanalyses on stained glass windows from Pavia Carthusian Monastery

Stained glass windows from the Carthusian Monastery of Pavia, dating back to the 15th century, were studied by combining two analytical techniques: electron probe micro-analysis (EPMA) and electron paramagnetic resonance (EPR). Chemical compositions and oxidation states of the transition ions, present as minor elements, were investigated by EPMA and EPR, respectively, in order to ascertain the role played by chromophorous ions in the glass coloration. The investigated glass can be defined as K-Ca glass, and the panes with red, green and blue colours were produced using flashing techniques.