Two Stangengläser from the collection of the Museum of Decorative Arts in Prague: Decorative techniques, material analyses, and conservation

The two Stangenglaser, tall cylindrical vessels from the beginning of the seventeenth century, are described in detail. The severely damaged Stangenglaser, decorated with diamond-point engraving and cold-painting, were challenging to treat. Research preceding the conservation revealed differences in decorating techniques. Samples of the paint layers were analyzed using micro-Fourier transform infrared spectroscopy. Two layers of resinous varnish with a middle layer of paint containing a plant gum were found on the Stangenglas with Allegory of Caritas and Zierotin coat of arms. In the plain paint layer of the Stangenglas with dancing couples, egg white was identified as the binder. The glasses, analyzed using scanning electron microscopy with energy dispersive X-ray spectrometry, had similar potash-lime-silica compositions, which seems to be characteristic for glass from Bohemian lands. Results of analysis contributed to the discussion about the possible provenance of the Stangenglaser, the glassworks at Wilhelmberg, South Bohemia.