Portable X-ray fluorescence spectroscopy（PXRF） was used for the first time to conduct a non-destructive，in-situ analysis of the tin gilding decorating the cave murals of the Kizil Grottoes in Xinjiang. In addition，this study used a metallographic microscope in combination with SEM-EDS and Py-GC/MS to analyze the micro-damage sustained by the foil materials，and to investigate the decorative techniques used to create the murals. The research results show that the element tin is present in 20 caves，which indicates that tin foil gilding was very common in the Kizil Grottoes. The results also show that the binding materials used with the tin foil contain dry oil，proteins and polysaccharide，and that a protective coating was painted over the gilding. By combining these results with other relevant research，it can be inferred that tin foil was used to imitate gold or silver foil decoration，or was used as a ground layer for the paintings. A preliminary study on the materials and techniques found at the Kizil Grottoes，as well as the origin and dissemination of this decorative style，suggests that this use of tin foil originated in ancient Kucha and was later adopted by Buddhist mural decoration practices in Bamiyan and northern India. The development and popularity of tin foil gilding was therefore closely related to the spread of Buddhism in the Western Regions and Central Plains of China. This study is meant to provide scientific reference material for research on the trade and cultural exchanges along the Silk Road in a specific historical period.

The Mogao Grottoes at Dunhuang，which represent a typical example of the Dunhuang caves，possess a wealth of historical，artistic and scientific value. Cave 55，which is located at the center of the site，contains wall paintings dating to the period from the Song dynasty to the Western Xia. This study comprehensively analyzes the materials and techniques used to create the murals in the cave by using multiple analytical methods，including X-ray fluorescence，scanning electron microscopes and Energy Dispersive Spectrometry，X-ray diffraction，and Pyrolysis gas chromatography and mass spectrometry. The results show that the structure of the murals includes a bottom layer of plaster，a paint layer，a surface layer of plaster，another paint layer，and a final layer of surface gilding. Straw was added to the coarse bottom layer of plaster as a reinforcement material，while hemp was added to the surface layer of fine plaster. The inorganic pigments used in the paints are mainly cinnabar，iron red，copper chloride，and broccoli，while the organic binding material used to fuse the layers of the murals together is animal glue. The results of this study not only provide a methodological reference for further analysis of mural-making materials and techniques，but also provide scientifically obtained information useful for the restoration of murals，both of which are of great significance for mural conservation.

By taking the original soil in cave 80 at the Maijishan Grottoes as a target sample，and by using soil from selected locations in the areas surrounding the cave temples as contrast samples，this study analyzes the degree of difference between the two sample groups by analyzing the mineral composition，chroma，granularity and soluble salt content of the different soils. The results show that the difference in mineral composition between the two sample groups is small（8.2%）， but the differences in color and grain size are large（3.1 and 17.8%）. Compared with the original earth in the cave，the mineral composition of the earth taken from selected locations fluctuates greatly（6.6%~27.9%），while differences in chromaticity are moderate（1.6~1.9 with a specific value of 4.7），the difference in grain size is relatively concentrated（13.3%~16.2%），and the soluble salt content is consistently less than 1%. The selection of soil from local sites is not entirely applicable，however，as thedifferences between the earth taken from various places fluctuates greatly. Generally speaking，the soil to be used in the restoration of cave temple murals should be selected from samples that are most similar to the original earth of the cave，as determined through laboratory analysis；a second principle for selection is that the use of“local materials” from adjacent areas is likely to provide the best soil available. This research recommends using soil from Xiaqu for the restoration of cave 80 at the Maijishan Grottoes，as comparative analysis of the two soil groups has confirmed that the composition of the earth from this location is quite similar to that of the cave.

The tomb of Xiao He，the father of Empress Qin’ai，is among the tombs of nobles from the Liao dynasty in Mazhangwa near Fuxin City，Liaoning Province，and contains a collection of murals that are rich in content for the study of the politics，economics，social culture and funeral customs of the Khitan people during the Liao Dynasty. Due to the need for public exhibition beginning in 2020，restoration work for these murals is urgently needed. In order to further understand the chemical makeup of these paintings and determine an appropriate restoration methodology，this study utilized a super depth of field microscope，SEM-EDS，confocal laser Raman spectroscopy，XRD and Py-GC/MS to research the pigments in the door god paintings on a white background in the tomb，as well as the binding materials used between the layers of paint. The research results show that the pigments used in the murals are mineral pigments，among which the red pigments are lead red and iron red， the black is carbon black，the yellow is iron yellow and lead yellow，the green is green stone，and the material used to bind the pigments is animal glue. The white background is composed primarily of quartz，calcite and kaolinite. An understanding of the elements used to create the door god mural can provide valuable reference material for future conservation and restoration of the murals in this tomb.

The Mogao Grottoes in Dunhuang are the most important ancient mural site in China and have preserved the mural art created from the Sixteen Kingdoms to the Yuan Dynasty（the 4th-14th century CE），a period of over a thousand years. These precious cultural artifacts are primary objects for research on the pigments used to create different colored paints，and on the painting techniques used in different eras and locations of the Silk Road. This paper summarizes the research conducted on the pigments and painting techniques found in the Mogao Grottoes，including an overview of the historical development of pigment analysis and detection technology, and proposes several new directions for future research.

Aiming at the disadvantages of accuracy and efficiency of the current manual investigation methods of mural diseases，this paper studies a new automatic edge extraction method. First，make the orthophoto map of the mural；Secondly，the SLIC super-pixel segmentation method considering compactness is applied to the orthophoto projection map to obtain the super-pixel with compact edge of classification rules；Thirdly，the maximum similarity region merging algorithm is used to cluster the super pixels to obtain the disease high-precision edge data；Finally，the region of the disease on the orthophoto map is obtained and expressed quantitatively and qualitatively. Experiments with real mural data prove the correctness and feasibility of this method. The research method provides a new idea for the automatic investigation of mural cultural relics.

Mural or wall paintings are important cultural heritage which are both valuable and vulnerable. Biodeterioration and biodegradation of murals caused by microbial activities can be from aesthetic alteration to material degradation and structure damage of the painting layers，leading to a substantial loss of the historical，artistic and cultural values. Microorganisms，including algae，lichens，bacteria，fungi and archaea，are known for their abilities to colonize a wide range of materials under various microhabitats. Near non-invasive and non-destructive sampling methods are being adopted and used to minimize the damage to the mural. The methods for analyzing microorganisms on cultural heritage are conventionally based on culturing and isolation，while the modern molecular methods are being applied increasingly to reveal the characteristics of biochemical functions and microbial communities of the whole microbiome associated with wall paintings. Mechanical/physical methods and biocides are the most frequently used to control microbial growth on cultural heritage，however，it is highly susceptible to failure or recurrence of microbial damage due to drug resistance. The local environmental conditions，e.g.，relative humidity（RH），temperatures and lighting，are the key factors that influence the biodeterioration of murals，climate change and extreme weather are challenges to the long-term preservation of wall paintings. In order to develop effective prevention and management countermeasures，the active microorganisms and the biochemical reactions of them，and preventive measures such as preservation environment regulation shall be focused more specifically in the future research. The most effective protection strategy for murals shall be based on a better understanding of the mural materials under the specific environmental conditions with scientifical protection strategies of minimum intervention onto mural，this requires the joint efforts of experts and scholars in the multidisciplinary of biology，chemistry，materials science，geology，environment and cultural heritage protection.