Rebecca J. Stacey

Despite the wealth of artworks from ancient Egypt in collections worldwide, the number of analytical studies on the organic media used in paints and adhesives is limited, especially because microsamples are often required. In this study, we used mass spectrometry–based proteomics to confidently identify the species and tissues of origin of proteinaceous materials in painted ancient Egyptian artifacts from several collections dating 1425 BCE to 400 CE. Proteomics confirmed the use of glue prepared from the collagen of multiple animals and revealed the presence of plant proteins, including sesame and moringa products, previously undocumented in ancient Egyptian artworks. This prompts additional discussions about the origins of these materials, their symbolic and religious meaning in connection with deities, and their value within the artistic, cultural, and economic contexts of ancient Egypt. Our study demonstrates that combining paleoproteomics results with other analytical methods, archaeological evidence, and textual sources sheds light on expected and more unconventional organic materials in painted artworks from ancient Egypt.

Paints and plasters from two pharaonic settlement sites in Nubia (northern Sudan) were analysed to investigate the presence and origin of organic binding materials. The town of Sai was founded around the time of the pharaonic conquest of Kush (Upper Nubia) around 1500 BC, with Amara West created as a new centre for the pharaonic administration of the region around 1300 BC. Recent fieldwork at both sites yielded examples of paint palettes, including several from houses. These provide a different economic and social context to funerary contexts upon which most previous research has been conducted, making this study the first to report on binding media for vernacular architecture in the Nile Valley. It is also the first study of binding media from Nubia. Gas chromatography mass spectrometry (GC-MS) analysis of methanolysed and silylated paint and plaster samples revealed a range of monosaccharides present in eight of the seventeen samples from Amara West, and in six of the seven samples from Sai. Interpretation of the data was supported by field collection and study of locally available botanical gums. The results indicate that mixtures of gums were in use as a pigment binder at both sites during the mid- to late-second millennium BC. The possibility that some of these plant gums could have been imported from the Mediterranean is also posited.

Black organic coatings and ritual deposits on ancient Egyptian coffins and cartonnage cases are important and understudied sources of evidence about the rituals of funerary practice. Sometimes, the coatings were applied extensively over the surface of the coffin, resembling paint; in other cases, they were poured over the mummy case or wrapped body, presumably as part of a funerary ritual. For this study, multiple samples of black coatings and ritual liquids were taken from 20 Egyptian funerary items dating to a specific time period (c. 943 to 716 BC). Multiple sampling from each object enabled several comparisons to be made: the variability of the black coating within one application, the variability between two applications on one object, and the variability from object to object. All samples were analyzed for lipids using gas chromatography–mass spectrometry (GC-MS), and 51 samples from across the 20 items were further analyzed for the presence of bitumen using solid phase separation followed by selected ion monitoring GC-MS. The majority of the black substances were found to comprise a complex mixture of organic materials, including bitumen from the Dead Sea, conifer resin, and Pistacia resin, providing evidence for a continuation in international trade between Egypt and the eastern Mediterranean after the Late Bronze Age. Both the coating and the anointing liquid are very similar to mummification balms, pointing to parallels with Egyptian embalming rituals and raising questions about the practical aspects of Egyptian funerary practice. Significance Previous studies of ritual black coatings on coffins from ancient Egypt have taken single small samples from objects of wide-ranging time periods and have conflated different types of application. This study takes 100 samples of black ritual liquids identified by type of application and precisely located on the objects, to allow the results to be fully contextualized within the wider discipline. It shows that black coatings on coffins were made using a remarkably consistent selection of natural products. The molecules identified in these black coatings overlap with those used in Egyptian mummification balms, which may suggest a link among separate applications: preparation of the body for burial, decoration of the coffin, and rites performed during the funeral.

A method has been developed for extracting poppy alkaloids from oily matrices, specifically lipid residues associated with archaeological ceramics. The protocol has been applied to fresh and artificially aged poppyseed oil and to residue from a Late Bronze Age Cypriot juglet in the collections of the British Museum. The juglet is of a type that has been linked with ancient trade in opium due to its poppy-head shape and wide distribution; it is a rare example of an intact vessel with contents sealed inside. Bulk analysis of the residue by GC-EI-MS and pyGC-EI-MS indicated a degraded plant oil and possible presence of papaverine. Analysis of the alkaloid extracts by HPLC-ESI-MS using both triple quadrupole and FTICR mass spectrometers detected the five primary opium alkaloids in fresh poppyseed oil and papaverine in most of the aged samples. Papaverine and thebaine were detected in the juglet residue, providing the first rigorous chemical evidence to support a link between this vessel type and opium, or at least poppies. The association of opium with oil raises new questions about the ancient purpose of the commodities within these vessels, and the low levels (ng g⁻¹) of opiates detected in this unusually well-preserved residue shed doubt on the scope for their detection in more fragmentary ceramic remains (potsherds). Papaverine was found to exhibit challenging carryover behaviour in all the analytical methods used in this study. The phenomenon has not been reported before and should be considered in future analyses of this analyte in all application areas.

This study gives an account of the organic components (binders and coatings) found in the polychromy of some fragmented architectural reliefs from the Palace of Apries in Memphis, Egypt (26th Dynasty, ca. 589-568 BCE). A column capital and five relief fragments from the collections of the Ny Carlsberg Glyptotek in Copenhagen were chosen for examination, selected because of their well-preserved polychromy. Samples from the fragments were first investigated using Fourier transform infrared (FTIR) spectroscopy to screen for the presence of organic materials and to identify the chemical family to which these materials belong (proteinaceous, polysaccharides or lipid). Only the samples showing the potential presence of organic binder residues were further investigated using gas chromatography with mass spectrometry detection (GC–MS) targeting the analysis towards the detection and identification of compounds belonging to the chemical families identified by FTIR. The detection of polysaccharides in the paint layers on the capital and on two of the fragments indicates the use of plant gums as binding media. The interpretation of the sugar profiles was not straightforward so botanical classification was only possible for one fragment where the results of analysis seem to point to gum arabic. The sample from the same fragment was found to contain animal glue and a second protein material (possibly egg). While the presence of animal glue is probably ascribable to the binder used for the ground layer, the second protein indicates that either the paint layer was bound in a mixture of different binding materials or that the paint layer, bound in a plant gum, was then coated with a proteinaceous material. The surface of two of the investigated samples was partially covered by translucent waxy materials that were identified as a synthetic wax (applied during old conservation treatments) and as beeswax, respectively. It is possible that the beeswax is of ancient origin, selectively applied on yellow areas in order to create a certain glossiness or highlight specific elements.