Scholarly article on topic 'Analysis of a Ptolemaic Mummy Foot from Slovene Ethnographic Museum'

Analysis of a Ptolemaic Mummy Foot from Slovene Ethnographic Museum Academic research paper on "History and archaeology"

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Procedia Chemistry
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Keywords
{"Egyptian mummy" / "Linen bandages" / Fibres / Binders / Pigments}

Abstract of research paper on History and archaeology, author of scientific article — Katja Kavkler, Marko Frelih

Abstract We analyzed a foot of an Egyptian mummy, which is supposed to originate from the Ptolemaic era. Only a foot with the lower part of the calf of is preserved in the Slovene Ethnographic Museum. The foot is bound into several layers of fabric. Another piece of fabric as well as two bones are part of the museum object, as well. The bandages of the mummy are arranged in a geometrical pattern and the sole is painted. We identified fibers in the textiles and analyzed their structure. Binding material was identified with which the bandages are glued as well as the pigments and binding media in the sole decoration.

Academic research paper on topic "Analysis of a Ptolemaic Mummy Foot from Slovene Ethnographic Museum"

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Procedia Chemistry 8 (2013) 159- 164

Youth in Conservation of Cultural Heritage, YOCOCU 2012

Analysis of a Ptolemaic mummy foot from Slovene Ethnographic

Museum

Katja Kavkler3*, Marko Frelihb

aInstitute for the Protection of Cultural Heriatge of Slovenia, Restoration Centre, Poljanska 40, 1000 Ljubljana, Slovenia bSlovene Ethnographic Museum, Metelkova 2, 1000 Ljubljana, Slovenia

Abstract

We analyzed a foot of an Egyptian mummy, which is supposed to originate from the Ptolemaic era. Only a foot with the lower part of the calf of is preserved in the Slovene Ethnographic Museum. The foot is bound into several layers of fabric. Another piece of fabric as well as two bones are part of the museum object, as well. The bandages of the mummy are arranged in a geometrical pattern and the sole is painted. We identified fibers in the textiles and analyzed their structure. Binding material was identified with which the bandages are glued as well as the pigments and binding media in the sole decoration.

© 2013 The Authors. Published by Elsevies B.V.

Selection and peer-review under responsibility of the IA-CS (Italian Association of Conservation Scientists) and University of Antwerp Keywords: Egyptian mummy; linen bandages; fibres; binders; pigments

1. Introduction

We analyzed a foot of an Egyptian mummy, which is supposed to originate from the Ptolemaic era (275 BC to 30 BC). Only a foot with the lower part of the calf of a mummy is preserved in the Slovene Ethnographic Museum under the inventory number EM 655 (Figure 1). The faith of the rest of the mummy is unknown. The mummified foot is from the collection of Baron Jozef Svegl, who was a diplomat in Egypt from 1859 to 1869 and developed interest for collecting Egyptian antiquities in this period. The foot was donated to Slovene Ethnographic Museum in 1934 by Ivan Svegl, the nephew of Jozef Svegl.

* Corresponding author. Tel.: +386 1 2343 168; fax: +386 1 2343 176. E-mail address: katja.kavkler@rescen.si.

1876-6196 © 2013 The Authors. Published by Elsevier B.V.

Selection and peer-review under responsibility of the IA-CS (Italian Association of Conservation Scientists) and University of Antwerp doi:10.1016/j.proche.2013.03.021

The foot is bound into several layers of bandages, as can be clearly observed at the broken end of the calf. Another piece of fabric as well as two bones are part of the museum object as well. The bones are presumably from the toes, since the foot is damaged in the region of the toes. However, the function of the additional piece of textile is unknown.

Figure 1: Photograph of the mummy foot with a part of calf, two bones from the toe region and additional piece of cloth,

stored in Slovene Ethnographic Museum.

The bandages of the mummy are arranged in a geometrical (coffered) pattern, typical of the Ptolemaic period [1][2]. The sole is painted in a geometrical pattern in rectangular form. Rectangles are of yellow, blue and red colour, outlined by black lines. Painted outer layer of the wrappings was a characteristic feature of the Roman (Ptolemaic) period in Egypt, as was the decoration with geometrical patterns [1]. Regardless of the condition of the body, the mummy was ornately wrapped and decorated, typically with complex geometric patterns [3].

The aim of the present study was to identify the materials used for winding round the corpse and for decoration of the mummy as well as to analyze their state of preservation.

2. Materials and methods

From the wrappings and separated cloth five samples were taken for analysis. Furthermore, one sample was taken from the adhesive material, binding the bandages together. Four samples were taken from the painted decoration of the sole.

For optical microscopy, paint chips were embedded in a polyester resin and polished to obtain cross sections, whereas the fibers were prepared on a glass slide soaked in distilled water. Olympus BX60 microscope was used with 50x magnification. Paint chips were observed in reflection mode and fibers in transmission mode. To determine the source of the bast fibers used for all textiles, we used polarizers and a compensator with X=530 nm. Type of the bast fibers was determined according to its morphology as well as interference colors [4].

On all samples FTIR microspectroscopy was performed. Samples were pressed in diamond anvil cell and analyzed in transmission mode on Spectrum 100 (PerkinElmer) spectrometer attached to the Spectrum Spotlight

200 (PerkinElmer) microscope. Spectra were scanned in the region between 4000 cm-1 and 500 cm-1 at the resolution of 4 cm-1 and 64 scans were averaged for each spectrum.

Pigments in the paint cross sections were analyzed using Raman spectrometer LabRam 800 (Horiba Jobin-Yvon). Laser at 785 nm wavelength was applied and spectra were scanned in the region between 100 cm-1 and 2000 cm-1. Time and filters were applied in accordance with materials' properties.

3. Results and discussion

All textiles, bandages as well as the additional piece of cloth were made of flax, as determined by optical microscopy from fibers' morphology and interference colors (Figure 2). Flax fibers are relatively thin (under 20 (im) and are well preserved. This can be concluded from well preserved lumen as well as from general appearance of the fibers, which have no observable damages.

Figure 2: Photographs of flax fibers of the sample taken from wrappings in daylight (upper left) and under crossed polarizers with 530 nm compensator in orthogonal positions (bottom left and right), indicating flax fibre.

Furthermore, good preservation of the textiles was confirmed with FTIR analysis. When comparing FTIR spectra of modern reference specimens and specimens taken from mummy wrappings, no major differences in appearance of the spectra were observed. No changes in intensities and positions of bands as well as no additional bands were observed. This means that no changes occurred in arrangement of cellulosic molecules and no depolymerisation proceeded due to oxidation or hydrolysis (Figure 3).

High crystallinity of the cellulose fibers was confirmed with quantitative analyses, as well. Total crystallinity index (TCI) was determined by comparing heights of two different cellulose bands [5][6]. Band at 2900 cm-1 is typical of aliphatic methylene (CH and CH2) bonds and remains relatively unchanged even after deterioration. On the other hand band at 1370 cm-1, typical of COH and HCC vibrations of cellulose and hemicelluloses, changes during supramolecular changes of cellulose and depolymerisation. If crystallinity decreases, a decrease of this band is observed [7][8]. High crystallinity indices were observed for all analyzed samples. They are even higher

than in modern reference specimens (Figure 4). The reason for this could be the lack of water, which could cause further intramolecular bonding.

4000 3500 3000 2000 15D0

Wavenumber [cm'1]

Figure 3: FTIR spectra of fiber from sample 2 taken from wrappings (red line) and contemporary reference flax sample (black line). Only slight differences in spectra appearance can be observed.

1,1 ■ 1,0 0.90.80,70.60,5 -0,4 -0,3

TCI (1370 cm"1/2900 cm'1)

-1-'-1-1-'-1-1-1-

EMA5 1 EMA5 2 EMA5 3 EMA5 4 EMA55

Specimen name

Figure 4: Comparison of total crystallinity index (TCI) of two reference samples (LIn1, LIn2), sample from additional piece of cloth (EMA5 1) and four samples taken from mummy wrappings (EMA5 2 to EMA5 5)

Binding material was identified, which was used to glue the bandages, using FTIR spectroscopy. It consists of polysaccharide, most probably vegetable gum. From the literature we know that in traditional embalming processes (in earlier period, around Tutankhamun's lifetime) the layers of wrappings were glued together with molten resin. This caused them to stick together and improve their rigidity [1][2]. The use of tree resins was due to religious purposes rather than for conservation [1]. Other researchers investigating mummies from Ptolemaic period report tree resins (e.g. cedar turpentine) to be found in embalming resin [9]. We found no literature on using polysaccharides as embalming materials. The separate piece of fabric, with unknown function, is soaked with proteinaceous material.

In the red paint we identified pigments in preparation layers as well as in red layer. The preparation layer consists of calcite and silicates. For the ground layer of paintings in Ptolemaic era mainly chalk and gum were used [10]. The main component in paint is burnt earth pigment, identified by presence of hematite and calcite. Black pigment used for lines forming geometric shapes was charcoal. We had many problems identifying blue pigment, since strong luminescence background occurred in Raman spectra. Therefore we tried with FTIR, where a spectrum of Egyptian blue was observed (Figure 5). Egyptian blue (calcium-copper tetrasilicate) was known at least from 3rd millennium BC and is one of the oldest synthetic pigments [11]. On the other hand, the ochre pigment could not be identified. Only presence of calcium carbonate and hematite was confirmed in the ochre layer. All identified pigments correspond to typical materials of the period, as described by other authors [10][12][13].

Wavenumber [cm'1] Figure 5: FTIR spectrum of blue paint, identified as Egyptian blue.

The binder identified with FTIR is starch. We do not know from which layer it comes, since it was extracted from the whole thickness of specimen. Since no other binder was identified, both ground as well as paint layers could have been mixed with starch binder. In the literature we found notes on presence of protein binders in paint layers on textiles from Ancient Egypt [13], but not for starch.

Additionally, we identified presence of oxalates, which are usually deterioration products of inorganic minerals with oxalic acid, either excreted by fungi or decomposition of organic materials. Calcium soaps were

detected as well. They could have been added to paint, acting as stabilizers [14]. They were used in encaustic, but in the analyzed object no wax was detected in the paint layers. They also cannot be present as deterioration product, since no greasy component was identified in the paints.

Despite the Egyptian mummy we analyzed is only partially preserved, the results give important information on materials used for mummification and decoration in Egypt in the Ptolemaic period as well as on their state of preservation.

References

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[11] Jaksch H, Seipel W, Weiner KL, El Goresy, A. Egyptian blue - cuproivaite. A window to ancient Egyptian Technology. Naturwissenschaften 1983;70:525-535.

[12] Edwards HGM, Villar SEJ, David AR, de Faria, DLA. Nondestructive analysis of ancient Egyptian funerary relics by Raman spectroscopic techniques. Anal Chim Acta 2004;503:223-233.

[13] Sack SP, Tahk FC, Peters T Jr. A technical examination of an ancient Egyptian painting on canvas. Stud Cons 1981;26:15-23.

[14] Boon JJ, Hoogland F, Keune K. Chemical processes in aged oil paints affecting metal soap migration and aggregation. In: Parkin HM, editor. AIC paintings specialty group postprints : papers pres. at the 34th annual meeting of the AIC of Historic & Artistic Works providence, Rhode Island, June 16-19, 2006, Washington: AIC; 2007, p. 16-23.