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S C I E N T I F I C H I G H L I G H T S

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Exploring ancient Egyptian illustration methods with X-ray diffraction Ancient illustration methods and pigments used on Egyptian papyruses from the Champollion Museum were investigated using high-resolution X-ray powder diffraction at beamline ID22. The results highlight a subtle balance between standardisation and creativity.

The ancient Egyptians used papyrus as a medium for communication and illustration, with the first illustrations appearing in the fifth and sixth dynasties (2500 2100 B.C.). Funerary documents, such as the Book of the Dead, flourished during the New Kingdom period as they were considered essential for entering the afterlife. The Champollion Museum in Vif, France, holds a collection of 280 papyrus fragments, many of which show scenes from the Book of the Dead. The colours used in these illustrations are typical of the Egyptian palette and include blue, green, red, pink, yellow and white, with different characters and elements of the illustrations outlined with a black line. In this work, researchers from the ESRF and the Néel Institute CNRS/UGA in Grenoble, France, with collaborators from the Champollion Museum, worked together to gain a deeper understanding of the illustration process used in ancient Egypt. A combination of optical microscopy, synchrotron X-ray powder diffraction, X-ray fluorescence and Raman spectroscopy was used to identify the pigments and their overall distribution.

Two of the papyrus fragments of the collection (PAP- 6 and PAP-12) were examined on beamline ID22, where X-ray fluorescence (XRF, Figure 124) and X-ray diffraction (XRD, Figure 125) experiments were carried out. Mixed Rietveld and Pawley refinement was carried out against the XRD data to quantify the fine fraction and to consider the heterogeneous microstructure of the pigments (Figure 125b). The main features of the so- called Godhead (PAP-6) can be seen on the iron map (Figure 124), revealing the presence of an underlying preparatory drawing in red hematite (Fe2O3). Yellow orpiment (As2S3) and blue cuprorivaite (CaCuSiO4, also known as Egyptian Blue) were used to colour the face of the God and its cap, respectively. An XRF reabsorption phenomenon occurs in regions where blue colour was applied on top of yellow, illustrating the layer superposition. The presence of Pb in the blue parts is related to the possible use of an additional drier in these specific parts, to improve the adherence of the large cuprorivaite crystals. Finally, the presence of a small amount of cinnabar associated with hematite in the solar disk of the God reveals the choice of a particular shade of red made by ancient Egyptian craftsmen.

The results suggest that the illustration process involved three main steps: first, a preparatory drawing in red hematite; then the application of different colours and pigments in a specific order, with lighter tones first and darker shades last; and, finally, the addition of a black contour line based on amorphous flame carbon. This illustration sequence, developed during the New Kingdom

Fig. 124: X-ray fluorescence maps recorded on the papyrus fragment PAP-6 revealing the presence of several chemical elements (ID22). Data were normalised to the incident X-ray flux, and for each of the maps, the brightest pixel corresponds to the highest

amount of the selected chemical element (logarithmic scale, arbitrary units).