Scientific investigation by technical photography, OM, ESEM, XRF, XRD and FTIR of an ancient Egyptian polychrome wooden coffin

Abstract

The focus of this study is to use a multi-analytical approach to map and identify the pigments used on a polychrome wooden coffin (Late Period), as well as to provide a deeper understanding of the painting techniques and the condition of the object. Moreover, the authors are significantly interested in the identification of the wood species. These were identified by observing the thin sections of samples under an optical transmission light microscope; the painted materials layered on the wood surface were analyzed by several scientific and analytical methods. Furthermore, the previous consolidation material and salts were also identified. The application of technical photography provided useful information about the spatial distribution of the surviving original pigments and the materials used in previous restoration interventions, in particular visible-induced luminescence, which played an important role to recognize spatial distribution of areas containing Egyptian blue, even if it is in traces or mixed with other pigments. However complete characterization of the pigments was only possible with the use of other techniques. ResumoEste estudo pretende usar uma abordagem multi-analítica para mapear e identificar os pigmentos usados num sarcófago de madeira policromada (Época Baixa), assim como proporcionar um mais detalhado conhecimento das técnicas de pintura e do seu estado de conservação. Além disso, os autores estão especialmente interessados na identificação das espécies de madeira. Estas foram identificadas através da observação, ao microscópio óptico de transmissão, de lâminas delgadas e a camada cromática sobre a madeira foi analisada com o recurso a diferentes métodos de exame e análise. Além disso foram igualmente identificados o material de consolidação utilizado numa intervenção anterior e os sais. A fotografia técnica proporcionou informação útil sobre a distribuição espacial dos pigmentos originais e dos materiais usados em anteriores intervenções. A luminescência visível induzida foi sobremaneira útil para se perceber a distribuição do azul egípcio, mesmo quando em concentrações vestigiais ou misturado com outros pigmentos. No entanto, a caracterização detalhada dos pigmentos só foi possível através dos outros métodos usados.

Non-invasive wood identification on parts of King Horemheb's ritual couches (New kingdom)

“…It also had considerable religious significance, since this tree, and its fruits, in particular, were associated with the goddess Nut. Although much used in ancient Egypt, sycamore fig wood is light, not of high quality and is prone to insect attack [18][19][20][21]. In this case, the use of the black resin that covered the wood surface of the couches may have reduced these drawbacks.…”

Identification of materials used in a wooden coffin lid covered with composite layers dating back to the Ptolemaic period in Egypt

“…Red earth or red ochre (hematite) of varying degrees of crystallinity was the most commonly used and reported red pigments during all ancient Egyptian periods [30,35]. Samples containing a small proportion of other minerals, including quartz, are best described as ochre, rather than as pure hematite.…”

“…The band at 1413 cm −1 (asymmetric) is identified as a CO 3 stretching and a O-C-O bending band, and the band at 871cm −1 is attributed to calcite. Two bands at 711 and 667 cm −1 are assigned to Fe-O-Fe and Fe-O stretching vibrations of hematite (Fe 2 O 3 ) [22,35].…”

“…The presence of Cl and Na elements in EDX analysis in all paint samples is indicative of the presence of sodium chloride (NaCl). This may probably be related to the burial soil that surrounded the wooden coffin [35] found in the stone sarcophagi, which was buried directly in soil [3].…”

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

“…In Figure 8 the infrared spectrum of gesso layer from sample 1 is shown. In this spectrum we can identify calcium carbonate and quartz; this was evidenced from the stretching vibrations of CO 3 2-group at 1396, the bending vibrations of C−O−C group at 870 and 711 cm −1 [9,[26][27], and the stretching vibrations of Si−O− Si group at 1099, 1043 and 779 cm -1 [26][27][28]. This spectrum also shows the presence of a band at 1619 cm -1 , assigned to C=O stretching of amide I and a band at 1557 cm -1 , assigned to N-H bending of amide II, which was confirmed by the N-H stretching band at 3328 cm -1 .…”