Signs of degradation of czech art nouveau mosaic glasses

0390201 - ÚACH 2013 RIV CZ eng C - Konferenční příspěvek (zahraniční konf.)
Rohanová, D. - Švarcová, Silvie - Hájek, T.
Signs of degradation of czech art nouveau mosaic glasses.
ACTA ARTIS ACADEMICA 2012: KNOWLEDGE AND EXPERIENCE IN THE FINE ART. PRAHA: Akademie výtvarných umění v Praze, 2012, s. 227-235. ISBN 978-80-87108-33-8.
[Interdisciplinary Conference of ALMA /4./. Praha (CZ), 21.11.2012-23.11.2012]
Institucionální podpora: RVO:61388980
Klíčová slova: glass mosaic * tesserae * glass corrosion * Victor Foerster * lead glass * Art Nouveau
Kód oboru RIV: CA - Anorganická chemie

Analyses of Art Nouveau mosaics from the church of St. Simon and Juda in Dolín near Slaný and from Holovousy, both most likely made by the workshop of Viktor Foerster, have shown that the author used the NaO-PbO-SiO 22 glass type and that he used the same glass also for restoration of The Last Judgment mosaic at the Prague Castle in 1890-1910. Despite the fact that lead glasses are more durable than potassium glasses, the material investigations identified corrosion processes on the surface of the glass pieces (tesserae) depending on their composition. Apart from the analyzed mosaic NaO-PbO-SiO2 glasses, we also used ancient sodium glasses (NaO-CaO-SiO2) and 22 potassium glasses (K2O-CaO-SiO2) from archaeological finds in Opava to demonstrate their different chemical durability. We also paid attention to fixation binders used in Art Nouveau mosaics. Inappropriate use of gypsum-containing binders is a significant cause of disintegration of the mosaics. Gypsum and gypsum-lime plasters are very sensitive to humidity. Capillary action of water is a very serious problem that endangers the overall lifespan of any mosaic.
Trvalý link: http://hdl.handle.net/11104/0219079