# Organic Materials Used for Giant Buddhas and Wall Paintings in Bamiyan, Afghanistan
###### Abstract  
Since 2004, scientific research on the damaged Giant Buddha statues and Buddhist paintings in Bamiyan, Afghanistan, has been conducted at various laboratories and large-scale facilities using mass-spectrometry techniques (GC-MS, LC-MS, LC-MS/MS, nano-LC/ESI-MS/MS), ELISA, and synchrotron-based micro-analyses) in parallel to conservation intervention. Studies on samples from these cultural heritage objects have shown that each is composed of a polychromatic multilayered structure with sizing layers, ground layers, painted layers, and glaze. The carefully produced complex multilayered structures were examined using optical microscopy (visible and UV light) as well as synchrotron-based infrared microscopy, both of which revealed various organic and inorganic components in each layer. High sensitivity bulk MS and ELISA methods were used to further identify details regarding organic materials, such as fatty acids and collagens, and these results suggest different vegetable oils and animal species of glues. For example, cow milk casein and cow skin glue were identified in the Eastern Giant Buddha, suggesting that casein was used as a sizing agent and the cow skin glue as a binder for painting. The wall paintings from Cave N(a) (mid-7 th century AD) were found to have horse glue used as sizing and drying oil (poppyseed/walnuts/perilla oils) as a binding media. The paintings' complex structures and their organic and inorganic materials were fully understood using both imaging and bulk methods, and thus, these methods help to reconstruct historical wall painting techniques in full. multilayered structure; binding media; sizing; glaze; proteomics; ELISA; synchrotron-based techniques; chromatography +
Footnote †: journal: _Sciences_  
Road, 2500 m in the highlands of Central Afghanistan. It has about 700 caves, of which around 50 have wall paintings. All have been subject to environmental degradation and human activity, such as looting, flaking, delamination, blackening, and alteration of pigments. 2. Prior to any conservation interventions in Bamiyan, it was necessary to obtain a thorough understanding of materials and techniques used in the caves. To this end, the NRICPT sampled and tested approximately 300 min fragments from wall paintings and both the EGB and WGB, with multi-analytical procedures. The wall paintings and polychromatic surfaces of the Giant Buddhas and are made from earthen renders with _a secco_ paintings (Figure 1). Since the site has been seriously damaged and most art of historical value has been lost, we employed a comprehensive analytical approach with state-of-the-art diagnostics to extract material and chemical information and reveal its historical and technical importance. Radiocarbon dating of the polychrome surfaces of the EGB and the WGB were conducted in Germany and Japan and reported elsewhere [3,4]. Data obtained in Japan (from samples provided by ICOMOS Germany) is shown in Figure 2. Following re-calibration using the IntCal20 [5], dates produced for the EGB were 440-460 AD, 478-496 AD, and 534-546 AD [1\(\sigma\)]. Dates for the WGB were 606-642 AD [1\(\sigma\)]. We also obtained radiocarbon dates for the wall paintings, which spanned from the 5 th to the late 8 th centuries [6]. The caves once served as Buddhist monasteries, and the two Giant Buddha states were constructed by different Buddhist seeds with different political backgrounds. Therefore, study of the painting materials and techniques is crucial for attributing the works and identifying their technological contexts. Figure 1: (**a**) EGB of Bamiyan, after demolishment in 2001. (**b**) Rare surviving wall painting of a partially vandalized seated Buddha, Foladi Cave 6. Black areas are the result of alteration in the green pigment, atacamite (photographed by [PERSON] in 2007).