Gold in the Alhambra: study of materials, technologies, and decay processes on decorative gilded plasterwork†

摘要: A complete study of the decayed gilded decorations stalactite vaults in Hall Kings Alhambra complex (Granada, Spain) has been carried out for first time. Preliminary investigations were situ using a portable Raman spectrometer and enabled identification tin (II) oxide black areas nearby golden flakes. This suggested presence an altered foil. Then, comprehensive characterization these was achieved through use complementary nondestructive techniques working on microsamples. Two main metallic structures identified by means scanning electron microscopy coupled to energy dispersive X-ray spectroscopy: (1) thin (1–2 µm) gold leaf (probably original), (2) redecorations with laminated structure formed placed over thicker (10–15 µm) Synchrotron Fourier-transform infrared microspectroscopy revealed proteinaceous glue fix directly plasterwork, whereas case structures, either or natural resin found. provided insight into decay processes affecting gildings: detachment metals due alteration organic materials employed as adhesives (forming calcium oxalates) oxidation In addition, two technologies false gilding have encountered. One based foil tinted look like varnish (composed drying oil resin), second made up tin–copper alloy (bronze) that appears severely degraded copper oxalate oxide, microspectroscopy. Copyright © 2014 John Wiley & Sons, Ltd.