Egyptian Blue Pigment Lab Report

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As a complementary technique, FTIR was applied to obtain information about the chemical compounds in the studied pigment samples. Figure 5(b) shows an FTIR spectrum recorded on the blue pigment sample (Ha. A). Egyptian blue pigment represents characteristic peaks lying mainly between 1280 and 1000 cm1, which are attributed to SiOSi stretching vibrations and mainly the intense bands at 1138 and
1054 cm1. Quartz was deemed to be present owing to the existence of the corresponding peak at 463 cm1 (SiO). The underlying ground layer showed a weak carbonate band at
1440 cm1 (probably of dolomite, CaMg(CO3)2) was recorded.
The band at 890 cm1 is due to the out-of-plane bending (n2) of carbonate group and the one of gypsum plaster has hydroxyl
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The climate of the area – as a part of Upper
Egypt – is characterized by large fluctuations of temperature; summer is likely to be abnormally hot and winter abnormally cool or cold. Schiegle et al.[29] reported that the migration of chlorine-bearing solutions is responsible for decomposing the
Egyptian blue pigments and forming of basic copper chloride.
On the basis of EDS and FTIR analyses, the thin preparation layer was identified as a mixture of dolomite and gypsum. There is no exact time of the first application of gypsum or anhydrite in decoration in ancient Egypt, and it may be used from the Fifth
Dynasty till the Roman time.[7] The optical examination of the paint layers shows a typical layer of white medium containing blue crystals and because of this white binding medium, the color of such layers is always pale blue. The macroscopic impression however may be a more intense blue. In addition, the artist probably wanted a light blue shade for a particular part of the decorations, in which case he has diluted the pigment in

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