Chemistry and art history

Secrets of the Bamiyan Buddhas

As it turns out, a genuine treasure was hidden behind the two Buddhas destroyed by the Taliban in 2001: caves decorated with 1000-year-old paintings depicting various scenes from Buddhist mythology. They are believed to be the oldest oil paintings ever found. This amazing discovery was made by an international team of researchers (1) using the European Synchrotron Radiation Facility (ESRF)(2) in Grenoble.

It all goes back to March 2001, when in Bamiyan, central Afghanistan, the Taliban destroyed two giant Buddha statues, probably dating from between the middle of the 6th and 7th centuries AD. The destruction of this heritage–a crime against culture–shocked the world. Yet behind the two stone giants, a hidden treasure of a different kind was uncovered: around 50 caves with walls decorated with religious frescoes that must have been made between the 5th and 9th centuries AD. Probably painted by monks or travelers passing through on the Silk road, they represent Buddhas, patterns and scenes related to Buddhist mythology. To the scientists' surprise, some of them are oil paintings–a technique believed to have been born between the 14th and the late 15th century in Flanders and Italy.³

“We analyzed tiny fragments–most of them less than a millimeter in size–taken from the paintings,” says Marine Cotte, a researcher at LC2RMF⁴ in Paris and at the ESRF in Grenoble, working with a team from the NRICPT⁵ in Tokyo. “Our goal was to identify the various ingredients used by the artists and to understand the painting methods of the time.” The scientists therefore carried out cross sectional analyses using the micro-imaging systems of the Grenoble synchrotron. This beam is so fine that it can be used to investigate materials on ever smaller scales. “The samples of paint are made up of several stacked layers, each of which is much thinner than the diameter of a hair,” Cotte explains. “The major problem lies in analyzing them separately. This is why we used ESRF's synchrotron radiation. By combining several analytical methods, we identified not only the original ingredients, but also the alteration products.”


The investigation revealed that the paints in the Bamiyan caves are made up of very finely powdered inorganic material, which are the pigments that provide color. Since they couldn't stick to the walls on their own, they were mixed with liquids in a paste that could adhere: these were organic binders like oil, resin, or glue. Two types of routine analyses were used to identify the various ingredients: X-ray diffraction and infrared spectroscopy. Using the first method, scientists discovered various pigments, and a large amount of white lead. The oldest of the manufactured pigments, white lead is a white powder that has been used since ancient times in paints and cosmetics.


The second method confirmed the identity of some of the pigments, and above all revealed the presence of organic matter. Several of the organic substances found, such as resins, plant gums, animal glues (proteins), and oil, were used as binders to make the paint stick to the walls. This method has been widely observed in wall paintings in Central Asia (such as the Sogdiana paintings). Further work carried out by an American team suggests this may be an oil manufactured from walnuts or poppy seeds. These analyses will make it easier to characterize the alteration processes at work on the surface of the few paintings that remain on the walls, and may help us understand how to preserve them. For years, political conflicts and wars have taken precedence over archaeological research in Afghanistan, and these remain a major obstacle to the study and preservation of sites. “This work,” Cotte concludes, “has revealed one of the oldest known examples of the use of oil in paint. But there are certainly other older examples we have yet to discover.”

Géraldine Véron