Left half of a panel painting rendering Nemesis and Harpocrates

Summary

The panel shown here depicts two well-preserved boards that are approximately the same width, with a motif representing a half-length representation in the upper-left corner, and shows an adolescent young man or boy in a full length on a dark greenish background. There is also the addition of a woman, dressed in a pink tunic with a light grey clavi (vertical stripes.)

Description of object

The left half of a panel painting consists of two well-preserved boards of approximately the same width, assembled vertically. On the left and upper and lower sides of the painting is an unpainted band, which corresponds to the original wooden frame, which is now lost. There are holes for the attachment of the frame placed at an irregular interval along the unpainted border.6 Strips of fabric are glued onto the joints of the boards, to cover/disguise it and to consolidate the attachment of the two slats.

The motif represents a half-length representation of a woman and in the upper left corner, an adolescent young man or boy in full length on a dark greenish background.

The woman is dressed in a pink tunic with light grey clavi (vertical stripes). The folds of the tunic on her chest are rendered with a darker pink. At the bottom of the panel, centrally placed in front of the woman, is a curved area of dark bluish-grey colour. This might render a himation, draped over the left shoulder (which is not preserved in this painting) and across the abdomen as seen in contemporary depictions of women in funerary art. The staff she holds in her hand is rendered in front/on top of this curved shape, making this explanation plausible.

The woman wears a necklace consisting of alternating rectangular blue gemstones/cabochons and oval elements which are yellow with a red oval centre. These yellow and red components of the necklace could represent gold elements with inlaid red semi-precious stones. Only her right arm is preserved. She wears a yellow snake-shaped bracelet on her wrist. Hear fingernails are painted red. She holds a long, thin, staff in her hand. The staff is black with yellow decoration, which runs along the left side of the staff and with perpendicular lines at regular intervals. It has a worked/ornamented termination, which is visible at the top of the panel to the right of the head of the young adolescent male just to the left of the joint of the two boards.

Only two thirds of her head, tilted slightly to the right, is preserved. Her dark-brown hair is parted in the middle and arranged in a bun in the back of her head. Her coiffure is ornamented with a sort of headgear in a lighter brown or yellowish colour, possibly a scarf arranged in two rows around her head. The details of the face are finely rendered with delicate shading. The eyes are only partially preserved, and it is impossible to tell where her gaze was directed.

In the upper left corner of the panel is a standing adolescent male or young boy. He is shown frontally, while his feet are pointed towards the right. He wears sandals and is dressed in a white tunic which reaches to his mid-calf and a fringed white mantle. He wears a black and grey sash or stole ornamented with what is probably a garland of pink flowers across the torso from the left shoulder to his right hip. The end of the stole falls vertically down the middle of his body, ending in a black fringe. His right arm is placed along his body, and he holds a thin black staff without any decoration in his right hand. His left arm if also placed along his body, while his forearm is stretched forward. His left hand is missing, but it is clear that he holds a pink item in his hand. He carries a small, yellow piriform vessel on his left wrist, which is passed through its handle. His head is shaved, indicated by the light grey colour, except for two small spots on his forehead and the childhood lock at the temple, which falls over his right shoulder. He wears a wreath/garland of pink flowers on his head, and a large cream-coloured halo without rays surrounds his head.

V. Rondot has made estimates of the original measurements of the panel: the left board is 9 cm wide, the right board is 11.3 cm wide, which gives a total preserved width of 20.3 cm. According to Rondot, the motif indicates that the panel originally consisted of four boards of equal width. If this is indeed correct, the panel would have had an original width of (20.3 × 2) 40.6 cm. However, it should be noted that a panel painting consisting of four boards is unique in this corpus (Rondot 2013, 148).

The woman, who is the main subject of the panel painting, has been interpreted as the goddess Nemesis, primarily due to the staff, which she holds in her right hand. The staff is finished with an only partially preserved black and yellow ornament, which Rondot suggests might render an Egyptian crown consisting of ram’s horns and an uræus with a sun disc (Rondot 2013, 274-275). The perpendicular double yellow lines arranged in regular intervals along its entire length identifies it as a cubit (measuring stick) with graduations. The cubit was the attribute of Nemesis, one of the most often depicted deities in the corpus of Egyptian panel paintings, thus providing a possible identification of the depicted woman (Rondot 2013, 273-275; Rondot 2015, 149). Based on his dress and attributes, the smaller haloed male figure in the left corner has been convincingly interpreted as the Hellenistic child-God Harpocrates (Rondot 2013, 275-277). Thus, the black stole and the garland of pink flowers as well as the situla, which he carries on his wrist, are typical in representations of Harpocrates in contemporary iconography

Choice of methods

Visual examination

• Macroscopic

Technical imaging

• UV
• VIL
• IR
• Raking light

Sampling

• Cross section
• Microscopy
• XRF
• FT-IR
• UV-VIS
• Raman
• GC-MS
• Radiocarbon (14C) dating, wood analysis, shotgun liquid chromatography tandem mass spectronomy.

Technical imaging

Multispectral imaging was performed with a modified Canon EOS 5D Mark IV camera body and a Canon EF 50mm f/2.5 Compact Macro lens. The following filters were used for image acquisition: XNite CC1 from MaxMax.com for visible light photography (VIS), XNite CC1, PECA 916, and Tiffen Haze 2E for ultraviolet induced visible fluorescence imaging (UVF), as well as a Schott RG830 for infrared photography (IRR) and visible light induced infrared luminescence imaging (VIL). A Midwest Optical Systems BP324 filter in combination with XNite CC1 yielded ultraviolet reflectance (UVR) images. The subtraction of an image at 635 nm shot with a Midwest Optical Systems BP635 filter from one at 735 nm (Midwest Optical Systems BP735) uncovered information about the presence of indigo as described by Webb et al 2014 and Bradley et al. 2020. For this imaging mode the abbreviation MBR (multi band reflectance image subtraction) is used. Light sources employed were incandescent tungsten lamps in combination with soft box diffusers, Excled LED RGB lamps (470 nm, 525 nm, and 629 nm), and Hoenle UVA SPOT 400/T lamps filtered with a Schott UG2A glass. The X-Rite Color Passport 2, Target-UV™ from UV Innovations, and a 99% Spectralon® diffuse reflectance standard were included in all images.

Other types of investigation

Fourier transform infrared (FTIR) spectroscopy

FTIR spectra were recorded with two different instruments. At the Center for Advanced Bioimaging (Copenhagen University), the samples were flattened onto a diamond window and analyzed in transmission mode between 600 and 4000 cm−1 using a Nicolet Continuum infrared microscope (Thermo Fisher Scientific Inc., Waltham, Massachusetts, U.S.) equipped with a liquid nitrogen cooled mercury cadmium telluride detector. The collected spectra were compared with reference libraries for compound identification.

Raman spectroscopy

For Raman measurements two spectrometers were also involved. In Copenhagen, at the Center for advanced Bioimaging (University of Copenhagen), the spectra were acquired on scrapings with an alpha300R Confocal Raman Microscope (WITec Oxford instruments, Ulm, Germany) equipped with two lasers emitting at 532 nm and 785 nm, respectively. The excitation laser power was on the order of 1 to 5 mW. A Zeiss EC Epiplan-Neofluar 50x lens and 300 and 600 g/mm gratings were used. The data was processed with WITec Project Five software, version 5.0.15.55, and compared with reference spectra. Raman spectroscopy on the cross sections was carried out in Boston. The different layers in several sections were examined with a DXR3 Raman microscope (Thermo Fisher Scientific Inc., Waltham, Massachusetts, U.S.), operated by Thermo OMNIC for Dispersive Raman software version 9.12.1002. All analyses from Boston were carried out with a 785 nm laser, 25 μm pinhole aperture, and 50x objective giving a spot size of approximately 1.0 μm. The standard grating that was utilized acquires data in the range 3374-32 cm-1, with resolution between 2.3 and 4.3 cm-1. Number of scans, scan time, and laser power were adjusted for each acquisition.

X-Ray Fluorescence (XRF) spectroscopy

XRF spectra were acquired with a handheld Tracer 5i XRF spectrometer equipped with a Rhodium tube (Bruker, Billerica, MA, USA). Two measurements at 15kV, 15 µA, with no filter and 40 kV, 7 µA, with a Ti/Al filter were taken for each location optimizing the detection of low and high Z elements, respectively. The data was processed with the Bruker Artax software Spectra, Version 8.0.0.476.

X-Ray Diffraction (XRD)

XRD data were collected using a PanAlytical Empyrean diffractometer equipped with focusing mirrors for Cu Kα radiation (λ = 1.541 Å) and a capillary spinner 8 (Malven Panalytical, United Kingdom). A Ni beta filter and a pair of 0.04 rad soller slits were used. The sample was ground in an agate mortar, placed in a 0.3 mm diameter quartz capillary, mounted on a rotating stage and measured in transmission geometry. Evaluation of the spectra and phase identification was carried out with the software X’Pert Highscore Plus v.4.8 (Malven Panalytical, United Kingdom) using the ICDD PDF 4+ database. Rietveld refinement was performed using the software TOPAS v.6 (Brucker AXS, Karlsruhe, Germany) with reference structures for Gypsum (ICSD 000210816), Anhydrite (ICSD 000371496), Bassanite (ICSD 010742787), Calcite (ICSD 000050586), Alunite (ICSD 010759141). Atomic positions and stoichiometry were fixed, while lattice parameters, average crystallite size and scale factors were refined.

Cross sections and microscopy

Samples for cross sectional analysis were mounted in Technovit 2000 LC resin (Kulzer Technik, Wehrheim, Germany) cured with blue light (Technotray Power, Kulzer Technik, Wehrheim, Germany). A two-step process was used for including a label resulting in 8 mm diameter cylinders. The final polishing was executed on an EcoMet 30 manual twin from Buehler (Lake Bluff, IL, USA) with 6 μm and 1 μm diamond suspension. Images of the polished cross sections were recorded with a Leica research microscope (Leica Microsystems GmbH, Wetzlar, Germany) in bright field mode with crossed polarizing filters and under UV illumination detecting the induced visible fluorescence.

Scanning electron microscopy (SEM) coupled to energy dispersive x-ray spectroscopy (EDS)

Cross sections of the paint samples were examined without carbon coating in a JEOL JSM-IT500 low-vacuum SEM (JEOL, Tokyo, Japan). The instrument was operated at 20 kV, with a beam current of ca.1 nanoampere. The chamber pressure was set at 50 Pa. EDS analyses were carried out with an Oxford Instruments X-MaxN spectrometer with 80 mm2 detector area, operated by Oxford ‘Aztec’ software, version 4.2 (Oxford Instruments, Abingdon, United Kingdom). The measurements included back-scattered electron images, individual point analyses, EDS maps, and line scans.

Shotgun liquid chromatography tandem mass spectrometry

The sample was processed, along with a protocol blank, following the protocol described in Mackie et al. (2018)1. Briefly, protein residues were extracted from the sample using a lysis buffer, and enzymatic digestion was performed with LysC and Trypsin. The resulting peptides were immobilised on C18 Stage-Tips and analysed by nano-liquid chromatography coupled with tandem mass spectrometry (nanoLC-MS/MS). The MS/MS spectra were identified with the MaxQuant software, matching them against a reference database containing all the publicly available sequences of proteins contained in the most common proteinaceous artistic materials: collagens, egg proteins, and milk proteins. In order to investigate the presence of protein residues originating from other sources, the spectra were then matched against a larger database (SwissProt, from UniProt), containing all publicly available and manually reviewed protein sequences. The matches were against fully tryptic peptide sequences, with no taxonomic restriction.

Proteins are considered confidently identified if at least two unique non-overlapping peptides are observed, unless otherwise specified. Peptides were considered species-diagnostic when, after BLAST search against the entire nrNCBI protein database, they were assigned to a single species, or to a limited number of species among which only one can be considered plausible, based on: (i) the nature of the samples, (ii) the geographic origin of the sample, and (iii) the dating of the sample. Peptides assigned to recurrent contaminant proteins were filtered out and not considered further. Contaminants include primate keratins (likely from the laboratory space or through human handling of samples), excess trypsin, and Bovine Serum Albumin (a common laboratory reagent)

Wood analysis

Because of the three-dimensional nature of wood anatomy, each tiny wood sample, irrespective of its size, was fractured manually to show transverse, radial longitudinal, and tangential longitudinal sections (TS, RLS and TLS). Each TS, RLS and TLS wood section was then mounted, uncoated, onto aluminum stubs. Examination of the wood samples and comparative reference specimens prepared and mounted using the same method was undertaken in a variable pressure scanning electron microscope (VP SEM), Hitachi S-3700N, using the backscatter electron (BSE) detector at 15 kV, with the SEM chamber partially evacuated (40 Pa). Magnifications ranged from x65 to x650. The preferred working distance was circa 14 mm but was raised or lowered from 11.1 mm to 15.7 mm as required. With the BSE detector, 3D mode (rather than Compositional) was preferentially selected to maximize the opportunity to reveal diagnostic features for identification. These details, along with the scale bar in microns (μm) can be seen on the data-bar on each of the three SEM images in the Results section. Further details on wood identification methods and techniques can be found in Cartwright 2015 and Cartwright 2020.

Radiocarbon (14C) dating

14C measurements of the panels and the organic binder were conducted at the Laboratory of Ion Beam Physics (LIP) at ETHZ (Switzerland). The wood samples underwent first a Soxhlet extraction (Bruhn et al. 2001) for removal of conservation treatments, which consisted of consisted of a round of 3 solvents starting with hexane (60°C, 1h), acetone (55°C, 1h) and ethanol (65°C, 1h). After which, the cellulose content of the wood was extracted by applying a modified base-acid-base-acid-bleaching method for cellulose extraction (Němec et al. 2010; Brehm et al. 2021) as follows: 1M NaOH (60°C, overnight), 1M HCl (65°C, 30’), 1M NaOH (65°C, 1h), 1M HCl (65°C, 30’), before being bleached with NaClO2 5% +0.1 ml 0.5M HCl (70 °C, 45’) and freeze-drying overnight. The selected paint material was chosen following an already established workflow (Hendriks et al. 2018), which highlights the need to characterize all paint components and ensure the presence of inorganic pigments only. The selected paint samples were cleaned by an acid wash (0.5M HCl, 60°C, 30’).

Bibliography

Rondot 2013, 146-48, 274ff., 259, 284; Parlasca 2004, 329-330, fig. 8; Schmidt 1899, 413-24, no. A497; Schmidt 1908, 639-640, no. E814.