Field and Laboratory Multi‐technique Analysis of Pigments and Organic Painting Media From an Egyptian Coffin (26th Dynasty)

Abstract

This paper describes the physico-chemical analyses performed on an Egyptian wood coffin on the occasion of its restoration in the hall of the National Archaeological Museum of Parma (Italy), with the aim of investigating the pigments and organic materials originally used. Pigment determination was performed both in situ by a portable energy-dispersive X-ray fluorescence (EDXRF) spectrometer and in the laboratory using a micro-Fourier-transforminfrared (micro-FTIR) and a Fourier-transform (FT) Raman spectrometer. The identification of organic materials was performed through gas chromatography -mass spectrometry (GC-MS) and micro-FTIR analysis. Amongst the pigments, special attention was paid to the green, which appeared to be severely degraded and was examined using powder X-ray diffraction (XRD) and scanning electron microscopy -energy-dispersive X-ray (SEM-EDX) in addition to the above-cited techniques. Other materials used in the polychromatic decorations are Egyptian blue, cinnabar and possibly orpiment, while calcium carbonate was used for the ground layer. The organic materials were identified as beeswax, mastic and gum arabic, sometimes as mixtures.

Raman spectroscopy of minerals and mineral pigments in archaeometry

“…The technology and trade between Spain and Aegypt were discussed. An Egyptian wood coffin was investigated by Bonizzoni et al using different techniques (EDXRF, micro FTIR, FT Raman, GC‐MS, XRD and SEM‐EDS). Only a few pigments (egyptian blue, cinnabar, probably orpiment) were identified.…”

Preliminary investigation of the materials and techniques used in a decorated wooden stick of king Tutankhamun

“…FTIR spectrum of the black resinous layer in samples 2 and 3 ( Figure 11) is more complex. It shows characteristic peaks of C-C stretching mode at 1644 cm , that may be assigned to the presence of Pistacia resins, such as mastic [9,34]. The spectrum from Figure 7b also shows weak absorption peaks at 1315 and 779 cm -1 , probably assigned to calcium oxalate, which was also determined in previous works [11].…”

“…Indeed, bands at 1621, 1315 and 779 cm -1 are strongly suggestive of calcium oxalate [35][36], besides those that can be assigned to proteinaceous based material at 1621, 1540 and 1409 cm -1 ; and bands assigned specifically to paraffin wax, at 2918, 2849, 1461 and 729 cm -1 . Finally, the spectrum of Figure 5 also shows some week absorptions at 1461, 1171 and 1099 cm -1 , probably related to pistacia resin [9,34]; however further analysis using micro-FTIR spectroscopy and GC-MS will be necessary to determine the identity of the varnish layer itself more precisely.…”

Gum arabic fractionation using synthetic membranes: The importance of fouling

“…Some of the earliest known uses were as an embalming agent and as a pigment binder and adhesive in paints by the ancient Egyptians (Bonizzoni et al, 2011). Gum arabic is still widely used today in the cosmetics, paints and, most notably, in the food and beverage industries.…”