Researchers have discovered what is believed to be the first use of oil painting at Bamyan in Afghanistan, (part of Persian Empire at the time of painting) predating European oil painting by some six centuries.
After the destruction of the Buddhas, 50 caves were revealed. In 12 of the caves, wall paintings were discovered. In December 2004, Japanese researchers discovered that the wall paintings at Bamyan were actually painted between the fifth and the ninth centuries, rather than the sixth to eighth centuries as previously believed.
The discovery was made by analysing radioactive isotopes contained in straw fibers found beneath the paintings. It is believed that the paintings were done by artists travelling on the Silk Road, the trade route between China and the West.
Scientists from the National Research Institute for Cultural Properties in Tokyo (Japan), the Centre of Research and Restoration of the French Museums-CNRS (France), the Getty Conservation Institute (United States) and the ESRF (the European Synchrotron radiation facility) in Grenoble analysed samples from the paintings, typically less than 1 mm across.
They discovered that the paint contained pigments such as vermilion (red mercury sulfide) and lead white (lead carbonate). These were mixed with a range of binders, including natural resins, gums (possibly animal skin glue or egg) and oils, probably derived from walnuts or poppies.
Specifically, researchers identified drying oils from murals showing Buddhas in vermilion robes sitting cross-legged amid palm leaves and mythical creatures as being painted in the middle of the 7th century.
It is believed that they are the oldest known surviving examples of oil painting, possibly predating oil painting in Europe by as much as six centuries. The discovery may lead to a reassessment of works in ancient ruins in Iran, China, Pakistan, Turkey and India.
Some have cautioned that the oils may in fact be contamination from fingers, as the touching of the painting is encouraged in Buddhist tradition. However analysis by spectroscopy and chromatography indicates an unambiguous signal for the use of oils rather than any other contaminant.
In addition oils were discovered underneath other layers of paint, negating the presence of surface contaminants.