Using Raman to Analyze Ancient Murals in Pompeii
Scientists used spectroscopic techniques to learn more about paintings in the blue room of Ariadne’s house.
To understand the science behind the degradation of historical landmarks, a team led by Nagore Prieto-Taboada of the University of the Basque Country in Spain, studied paintings in an ancient home in Italy (1).
The home belonged to Ariadne, the Ancient Greek figure, and is in the Regio VII of the Archaeological Park of Pompeii. Exposure from natural elements including rainfall and pollution, caused the murals to degrade over time. For example, room 22, also known as the blue room, was once adorned in blue decorations is now different hues of grayish green.
Vesuvius and Pompeii | Image Credit: © dbvirago - stock.adobe.com
The team, whose work was published in the Journal of Raman Spectroscopy, used a variety of analysis techniques on the degraded sections of Room 22. By using a combination of in situ and laboratory spectroscopic analyses by means of non-destructive X-ray fluorescence, infrared and Raman spectroscopies, they identified the original pigments and materials used in the conservation works. They also used Raman spectroscopy to analyze the stratigraphic distribution of the original pigments in detail, revealing an inner layer of Egyptian blue mixed with celadonite was detected under a layer of pure Egyptian blue.
Celadonite is believed to have been an inexpensive pigment used to reduce painting costs. The presence of atmospheric gasses also likely contributed to the degradation of the paintings, according to Raman data.
Historical artifacts do wither with time and enough exposure to the environment. However, using spectroscopic techniques can help scientists better understand how ancient pieces got to their present condition and what they were like when first created.
Reference
(1) Prieto-Taboada, N.; de Vallejuelo, S. F-O.; Santos, A.; Veneranda, M.; Castro, K.; Maguregui, M.; Morillas, H.; Arana, G.; Martellone, a.; de Nigris, B.; Osanna, M.; Madariaga, J. M. Understanding the degradation of the blue colour in the wall paintings of Ariadne's house (Pompeii, Italy) by non-destructive techniques. J. Raman Spectrosc. 2020, 52 (1), 85–94. DOI: https://doi.org/10.1002/jrs.5941
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