Materials and techniques of a Spanish renaissance panel painting

A technical examination of a Spanish altarpiece attributed to Bartolomé Bermejo (1468-1495), belonging to the Hispanic Society of America, was carried out. Analytical methods used in this study were X-radiography, infrared reflectography, optical microscopy (reflected light and polarized light), cross-section staining tests, scanning electron microscopy, gas chromatography-mass spectrometry, Fourier transform infrared spectroscopy and carbon-14 dating. A number of unusual techniques were identified including: the use of cotton and flax fibres for internal strength in the halo relief, the lack of a bole layer, the use of an orarge-coloured oil mordant under the gilding, the use of powdered gold over the entire gilded surface and the use of an egg-white binding medium. The carbon-14 dating placed the panel in the 1530s, which will lead to a new attribution.