analysis of red paint and filling material from the sarcophagus of queen hatshepsut and king...
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Analysis of Red Paint and Filling Material from the Sarcophagus of Queen Hatshepsut andKing Thutmose IAuthor(s): Richard NewmanSource: Journal of the Museum of Fine Arts, Boston, Vol. 5 (1993), pp. 62-65Published by: Museum of Fine Arts, BostonStable URL: http://www.jstor.org/stable/20519754 .
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RICHARD NEWMAN
Analysis of Red Paint and Filling Material from the Sarcophagus of Queen Hatshepsut and King Thutmose I
Red Paint
The reddish color of the sarcophagus exterior is due to red-colored paint; thick deposits can be seen in hieroglyphs and other recessed areas, while only thin washes occur on polished stone surfaces. Six samples from the left (east) side were analyzed by electron microprobe,' Fourier transform infrared microscopy (FTIR),2 and gas chromatog raphy/mass spectrometry (GC/MS),3 to identify the pigments and binder(s). The analyses indicate that the red paint, which is of similar if not identical composition in all of the samples, contains red earth (or ochre), the only red pigment that has been found to date in ancient Egyptian paints. Kaolinite (a clay mineral) and quartz are components of this earth pigment, as indicated by the FTIR spectra (fig. i). The spectra also suggest that the pigment was bound with a plant gum, a type of binder that was common in ancient Egypt.4
Plant gums can be hydrolyzed to yield simple sugars, the types and relative amounts of which vary somewhat from one gum to another.5 Two samples of paint were analyzed for simple sugars by GC/MS. The samples gave virtually identical results, showing the presence of large amounts of xylose and glucose, and smaller amounts of fucose, rham nose, galactose, and possibly arabinose (fig. 2). These results suggest that more than one sugar-containing material is present in the paint.
One component may be gum tragacanth, a gum that could have been available in ancient Egypt (xylose and fucose are important sugars in this gum). Glucose is not usually found in plant gums, although it is present in honey, plant juices, sugar, and some seeds; perhaps some sugar (in the form of plant juice or honey) was added to make the paint a little stickier.
Exactly why this red paint is present on the surface is not certain. As speculated in the preceding article,6 it may simply have been brushed or smeared over the surface as a guide for the stoneworkers polishing the stone. Thus the thicker deposits found in the hieroglyphs and other recessed areas of the design may be fortuitous rather than indicating intentional filling of these design elements with red paint. There are no indications of other colors anywhere on the exterior of the sar cophagus, although paint does remain on the figures on the inside ends (these figures were added during alteration of the sarcophagus).7
Filling Material in Altered Inscriptions
During alteration of the sarcophagus, portions of many inscriptions were filled with a brownish-black material. One sample from a charac ter on the top edge of the left (east) side was analyzed by a combination
RICHARD NEWMAN is Research Scientist, Research Laboratory, Museum of Fine Arts, Boston.
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NEWMAN: Analysis of Red Paint
Fig. i. Fourier transform infrared absorption Kao spectra of two red paint samples from the Qtz 1
sarcophagus exterior. Peaks marked "Kao" are due to kaolinite, those marked "Qtz" to quartz, both of which are components of the red pigment. Peaks due to the paint binder are also marked. Qtz
Binder
Kao Binder - XKao
Kao
Kao Binder Qtz 44 ~~~~~~~~~~~~~~~~Binder
Kao I I I 'I I T
4000 3500 3000 2500 2000 1500 1000 600.0
WAVENUMBERS
Fig. 2. Portion of total ion chromatogram Abundance from hydrolyzed sample of red paint from a 40000 recessed area of the design on the sarcoph- Glucose agus exterior. Simple sugars, analyzed as 35000 Xylose oxime-trimethylsilyl derivatives, are labeled (most give rise to two separate peaks, as indi- 300000 cated).
25000 Arabinose
20000 GaadseGal+Glu Fucose
15000- Rhamnose Rh
10000 F
500
Time - 11.50 12.00 12.50 13.00 13.50 14.00 14.50 15.00 15.50
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JOURNAL of the Museum of Fine Arts, Boston VOL. 5, I993
Abundance Palmitate Fig. 3. Portions of total ion chromatogram 60000- / from methylated methylene chloride extract
i of a sample of fill from an altered inscription. 50000 Upper trace shows major peaks, all due to
fatty acids as indicated. Lower trace is an ex 40000- panded portion of the chromatogram, show
ing some of the less abundant compounds 30000 Stearate detected, which mainly consist of straight 20000 A l lIr| chain hydrocarbons (labeled "H," preceded 20000
- Myristate C-15 acid C-17 acid by number of carbon atoms) and fatty acids
(labeled "A," again preceded by number of 10000 4, carbon atoms).
0 I ,,, ., . , I' Time 9.60
. 0.0. 0 11.00 12.00 13.00 14.00 15.00 16.00 17.00
Abundance 1 8A
35000 22A24
30000
2500027 29
20000 19A 2A 23AH25
15000 - 24H
10000
5000
23H 0 ' 'Il. . . . Il. . . . . ..l lIl l.
Time . 15.00 16.00 17.00 18.00 19.00 20.00 21.00 22.00 23.00
of the same techniques used with the red paint. The sample is mostly organic in nature, and contains little or no inorganic filler (a very small amount of calcium carbonate was detected). The principal compounds detected by GC/MS were fatty acids (fig. 3, top). These are present as free fatty acids in the sample, rather than in the form of triglycerides (the form in which they occur in vegetable oils).8 The source of these fatty acids may be an animal source, given the relative abundance of
myristic acid. Among the minor peaks in the chromatogram is a series due to hy
drocarbons (fig. 3, bottom); the source of these is not clear, but does not appear to a plant wax or beeswax, nor does the pattern resemble that of the hydrocarbons found in bitumen or asphaltum. GC/MS analysis detected traces of two compounds indicative of mastic resin, a type of resin that would have been available in ancient Egypt.9 No sugars were detected by GC/MS in a different portion of the sample, so no gum is apparently present. The FTIR spectrum suggested that a protein-con taining material, such as animal glue, could also be present. Thus the fill was made from a mixture of materials, which included mastic resin and a fatty substance, perhaps animal fat.
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NEWMAN: Analysis of Red Paint
Notes
i. The elemental compositions of small por tions of the samples were analyzed by qual itative energy-dispersive X-ray fluorescence
in a Cameca MBX microprobe (Dept. of Earth
and Planetary Sciences, Harvard University).
2. Samples were pressed in a diamond anvil
cell and analyzed on a Nicolet 5 ioP FT-IR
spectrometer with an attached Nic-Plan in
frared microscope at a resolution of 8
wavenumbers; 300 scans were co-added.
3. Samples were hydrolyzed and derivatized
following the procedure described by D.
Erhardt, W. Hopwood, M. Baker, and D. von
Endt ("A Systematic Approach to the Instru
mental Analysis of Natural Finishes and
Binding Media," American Institute for Con
servation Preprints of Papers Presented at
the Sixteenth Annual Meeting, New Or
leans, Louisiana, June 1-5,1988 [Washing
ton, D.C., 1988], pp. 67-84), except derivati
zation was carried out with 30 microliters of
a lab-prepared oxime reagent (8.5 mg hydro
xylamine hydrochloride/ml in pyridine) and
10 microliters of trimethylsilylimidazole.
Analyses were carried out on a Hewlett Pack
ard 5890 capillary gas Chromatograph with
an HP 5 971A mass selective detector. Split
sampling was utilized, with a non-polar col
umn. The mass spectrometer was operated in selected ion monitoring mode, using a
program that included the five major ions of
each of eight common simple sugars. Iden
tifications were made on the basis of renten
tion time and mass spectra with reference to
simple sugar and gum standards prepared and analyzed by the same procedures.
4. A. Lucas and J. R. Harris, Ancient Egyp tian Materials and Industries (London, 1962,
1989 reprint), pp. 5-6; and Catherine Vieil
lescazes and Daniel Lefur, "Identification du
liant dans la peinture murale ?gyptienne
(temple de Karnak), Bulletin del? Soci?t?
d'Egyptologie Gen?ve 15 (1991), pp. 95-100.
5. See, for example, J. Twilley, "The Analysis of Ex?date Plant Gums and Their Artistic
Applications: an Interim Report," in Ar
chaeological Chemistry III, ACS Advances
in Chemistry Series, No. 205 (Washington,
D.C., 1984), pp. 357-394
6. See preceding article, p. 37.
7. Ibid., p. 49.
8. A crushed sample was saponified and ex
tracted following a procedure described by D. Erhardt et al. (note 3). Methylation was
carried out with 10 microliters of dimethyl formamide dimethyl acetal. GC/MS analysis
was carried out both with the mass spec trometer in scan mode (50-500 amu) and
selected ion monitoring mode, utilizing a
program that includes characteristic ions for
fatty acids, wax hydrocarbons, hopanes of
asphaltum and bitumen, and some of the
compounds found in pine and mastic resins.
A second portion of the sample was ex
tracted by heating in m?thyl?ne chloride and
then methylated before analysis by GC/MS.
The profiles of fatty acids in the saponified
sample and m?thyl?ne chloride solution
were essentially identical, indicating that
the fatty acids are not present in the form of
esters (as in triglyc?rides), which the FTIR
spectrum also indicated.
9. The compounds, detected by selected ion
monitoring in the methylated m?thyl?ne chloride extract, were methyl moronate (base
peak, m/z 189; molecular ion, m/z 468) and
methyl oleanonate (base peak, m/z 203; molecular ion, m/z 468). For a discussion of
the source(s) of this resin in antiquity, see J. Mills and R. White, "The Identity of the Res
ins from the Late Bronze Age Shipwreck at
Ulu Burun (Kas)," Archaeometry 31 (1989),
pp. 37-44
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