How it began
The paintings sit in caves cut into the cliff behind the two giant Buddha statues at Bamiyan, in central Afghanistan. The caves hold murals made between the 5th and 9th centuries CE, and the oil-based ones are dated to the mid-7th century. They show Buddhas in vermilion robes seated cross-legged among palm leaves and mythical creatures.
No painter is known by name. The research team that studied the murals thinks they were probably the work of artists who traveled the Silk Road, the trade route linking China, Central Asia and the West.
How it works
The murals are built up in many thin layers of inorganic pigment mixed into organic binders. In 12 of the 50 caves studied, the binder in some layers was a drying oil, perhaps walnut or poppy seed oil, which hardens into a film as it reacts with air. Other layers used natural resins, proteins that point to hide glue or egg, gums, and in some cases a resinous layer like a varnish. Lead white was used heavily among the pigments.
The oil was identified by analyzing cross-sections of tiny samples at the European Synchrotron Radiation Facility, using infrared micro-spectroscopy, X-ray fluorescence, X-ray absorption and X-ray diffraction to read each layer separately.
What lasted
The finding changed the accepted history of a major painting technique. Many European art history books had placed the start of oil painting in 15th century Europe. The Bamiyan murals show drying oils used as a paint binder hundreds of years earlier in Central Asia. Yoko Taniguchi, who led the team, called them the earliest clear example of oil painting in the world, and noted that ancient Romans and Egyptians knew drying oils but used them only in medicines and cosmetics.
Where it stands today
The caves were damaged when the Taliban destroyed the two Buddha statues in 2001, and they have also suffered from a harsh natural environment. The samples were studied as part of a UNESCO conservation project for the Bamiyan World Heritage site, by scientists from the National Research Institute for Cultural Properties in Tokyo, French museum research laboratories, the Getty Conservation Institute and the ESRF. Their results were published in 2008. The researchers said that studies of painting in Central Asia remain scarce, and that more work is needed to understand techniques along the Silk Road.
