Analysis of Nasrid Polychrome Carpentry at the Hall of the Mexuar Palace, Alhambra Complex (Granada, Spain), Combining Microscopic, Chromatographic and Spectroscopic Methods*†

Abstract

The pigments, binders and execution techniques used by the Nasrids to polychrome carpentry in the Hall of the Mexuar Palace at the Alhambra (Granada, Spain) were studied using optical microscopy, scanning electron microscopy with EDX analysis, selective staining techniques and gas chromatography -mass spectrometry. This pioneering investigation presents the first results of a research project devoted to filling gaps in the knowledge of Nasrid art, traditionally approached by stylistic studies. Moreover, it is essential for the polychromy conservation of the studied artworks, and will help to clarify historical and painting uncertainties in the Alhambra monument. The palette consists of a limited range of colours: white (lead-base pigment), red (cinnabar and red lead), blue (lapis lazuli), black (carbon-based) and false gold (golden tin). Tempera grassa was the painting technique identified. Two types of grounds were used: (i) gypsum in calligraphy decoration for the false gold technique, and (ii) synthetic minium in geometric drawings in carpentry. Organic insulating layers of linseed oil were used between paint strata. Artists applied synthetic minium to protect the wood ( Juglans regia and conifer) against attack by xylophages. To lighten the surface darkened by this ground layer, powdered tin was added to achieve a metallic lustre.

Raman and Fourier transform infrared microspectroscopies reveal medieval Hispano–Muslim wood painting techniques and provide new insights into red lead production technology

“…Despite being so narrow that could be misinterpreted as Raman features, these bands have been demonstrated to be due to the luminescent emission arising from other components of lapis lazuli rock excited only when 785 nm laser is employed . These features, due to mineral impurities, can be used to distinguish easily the natural pigment from synthetic ultramarine blue . In fact, in some of the spectra recorded, the characteristic band of lazurite at 548 cm −1 was almost imperceptible (see Figure ), which points to the use of a pigment with many impurities.…”

“…Wooden ceilings have a long tradition in the Hispano–Islamic area attaining their greatest splendour during the Nasrid period. They have been mostly studied from a stylistic point of view, being scarce the scientific investigations aimed at the identification of materials and techniques employed in their decoration . The objects of study are two polychrome panelled wooden ceilings located in the Alhambra monumental ensemble (Granada, Spain).…”

Methodology for characterising microlayers in historical plasterwork

“…gypsum and lime) as they can present distinct properties under crossed nicols. The microstructure, texture, and mineralogy of each mineral can also studied by examining the optical properties of each mineral [3].…”

“…The study of microlayers is a common option in the examination of works of art such as paintings or polychrome sculpture and carpentry [2,3]. However, in architecture it tends to be ignored either to simplify matters or due to ignorance of the available techniques.…”

Analytical study of Roman and Arabic wall paintings in the Patio De Banderas of Reales Alcazares’ Palace using non-destructive XRD/XRF and complementary techniques

“…Coloured pigments were applied when the walls were still damp. In Hispanic monuments with Islamic iconography, evidence of painted fresco decorations has been found (Rallo Gruss, 2003); however, this type of artwork has not been widely studied from a scientific point of view (Cardell et al, 2009). The palette of ornamentation of Islamic buildings is dichromatic (usually red and white), and its design is geometric and repetitive.…”