Study on blue pigments in Cave 256, Mogao Grottoes: Five dynasties, Song Dynasty and Qing Dynasty

Study on blue pigments in Cave 256, Mogao Grottoes: Five dynasties, Song Dynasty and Qing Dynasty | Research Square window.SnipcartSettings = { analytics: { enabled: false } }; (function() { var accessVector = localStorage.getItem('access_vector') || ''; window.dataLayer = window.dataLayer || []; if (accessVector) { window.dataLayer.push({ user: { profile: { profileInfo: { snid: accessVector } } } }); } })(); (function(w,d,s,l,i){w[l]=w[l]||[];w[l].push({'gtm.start':new Date().getTime(),event:'gtm.js'});var f=d.getElementsByTagName(s)[0],j=d.createElement(s),dl=l!='dataLayer'?'&l='+l:'';j.async=true;j.src='https://www.googletagmanager.com/gtm.js?id='+i+dl;f.parentNode.insertBefore(j,f);})(window,document,'script','dataLayer','GTM-K279D39R'); Browse Preprints In Review Journals COVID-19 Preprints AJE Video Bytes Research Tools Research Promotion AJE Professional Editing AJE Rubriq About Preprint Platform In Review Editorial Policies Our Team Advisory Board Help Center Sign In Submit a Preprint Cite Share Download PDF Research Article Study on blue pigments in Cave 256, Mogao Grottoes: Five dynasties, Song Dynasty and Qing Dynasty Bi Wen Shui, Zong Ren Yu, Qiang Cui, Zhuo Wang, Zhi yuan Yin, and 2 more This is a preprint; it has not been peer reviewed by a journal. https://doi.org/ 10.21203/rs.3.rs-1266982/v1 This work is licensed under a CC BY 4.0 License Status: Under Review Version 1 posted 4 You are reading this latest preprint version Abstract Murals of Cave 256, Mogao Grottoes consist of several layers, with the outermost layer overlays all others. The bottom layer was painted in the Five Dynasties. The outermost layer was mural of the Song Dynasty. Statues were repainted in the Qing Dynasty. We found that different blue pigments are used through research of murals and statues of different dynasties in Cave 256. In order to know the type of blue pigments, technology such as X-ray diffraction, microscopic FTIR spectroscopy and polarizing microscope were used for analysis of trace samples based on non-destructive research through the portable X-ray fluorescence. As a result, we know that Lazurite was used as blue pigment in murals of the Five Dynasties and Azurite was used in the Song Dynasty. Smalt used in statues of the Qing Dynasty was first discovered in Mogao Grottoes. Difference in blue pigments reflects the social development at that time to a certain extent. It can be inferred from the discovery of smalt that statues of the Qing Dynasty in Cave 256 were repainted in the first half of the 19th century. Mogao Grottoes mural statues Cave 256 Lazurite Azurite Smalt Figures Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Introduction Dunhuang Mogao Grottoes is located 24 kilometers southeast of present-day Dunhuang City. As a comprehensive art combining architecture, sculpture and mural painting, it is the largest, longest lasting and the most informative site of grottoes temples in China and the whole world. Construction of Mogao Grottoes lasted for almost a thousand years from the second half of the 4th century to the 14th century. There was no new cave were excavated after the Ming Dynasty. A large number of murals and statues were repainted in the Qing Dynasty. There are about 45,000m 2 of murals and over 2,200 statues in Mogao Grottoes[ 1 ], which are important physical materials for studying the history of materials and craftsmanship of ancient Chinese murals and statues. Cave 256 is located on the second floor of the central area of the southern area of Dunhuang Mogao Grottoes, about 200 meters north of the nine storeys pagoda of Mogao Grottoes(Fig. 1 ). It has a relatively large area, with over 500m 2 of murals and 7 statues[ 2 ]. According to scholars, Cave 256 was built by Cao Yuanshen, the third military governor of Guiyi Army (a local armed regime that originated from the Tang Dynasty). It was founded in the Five Dynasties[ 3 ] and repaired during the Zhenzong period of the Northern Song Dynasty by Murong Yanchang, the military director of Yu Men Town of the Guiyi Army, and his wife Yan. The bottom layer was covered and a new layer of murals was painted[ 4 – 6 ]. Statues were repaired and repainted in the Qing Dynasty. Blue is highly regarded in ancient Chinese culture[ 7 ]. As one of the three primary colors, it is the most basic color in painting. It symbolizes eternity, nobility and purity and is loved by people in different times. It is also one of the most important colors of murals in the Mogao Grottoes. Based on previous research results, blue pigments used in murals and statues of the Mogao Grottoes are Lazurite[ 8 , 9 ] (from the Sixteen Kingdoms to the Northern Zhou Dynasty), Azurite[ 10 ] (the Sui Dynasty to the Five Dynasties), indigo blue[ 11 ] found in individual caves and artificial ultramarine used in repainting in Qing Dynasty[ 12 ]. In this study, scientific analysis methods are used to study types, usage techniques and sources of different blue pigments used in murals and statues of Cave 256 in the Five Dynasties, the Song Dynasty and the Qing Dynasty, providing new ideas for analysis of history of blue pigments used in the Mogao Grottoes. Materials And Methods Analysis equipment and parameters (1) Portable X-ray fluorescence analyzer The Thermo XL3t-800 Portable X-ray fluorescence analyzer is used for element analysis of pigments. It uses silver target. The spot diameter is 1cm. The analysis condition is 50kV/40µA (maximum), the detection time is 1min, and the soil mode is used. (2) Digital microscope VHX-600E digital microscopes manufactured by KEYENCE are used. Microscope lens model is VH-Z20R (20X-200X). VHX-600E built-in floodlight is used for observation. (3) X-ray diffraction analyzer The Rigaku Dmax/2500X X-ray diffraction analyzer is used for phase analysis of pigments. It has copper target. The analysis voltage is 40kV and the current is 100mA. Scanning is continuous. The scanning range is 5°-70°. Graphite monochromator is used for filtering. (4) Microscopic FTIR spectroscopy The Thermo Scientific Nicolet iN10 MX Microscopic FTIR spectroscopy is equipped with liquid nitrogen cooled MCT/A detector and has transmission mode. The measuring range is 4000-675cm −1 , and the spectral resolution is 4cm −1 , with 128-time scanning. (5) Polarizing microscope DM2700P polarizing microscope (Lycra, Germany) is equipped with DMC2900 camera (magnification 50×, 100×, 200×, 500× and 1000×). (6) Micro-area X-ray fluorescence spectrometer As for German Bruker ARTAX-400 mobile micro-area X-ray fluorescence spectrometer, input voltage is 30KV, input current is 900µA, test time is 300s, X-ray tube uses Mo target with fine focal spot and helium gas environment is used for test. The analysis and test results are compared with the standard working curve fitted by glass standard samples (Corning-B, Corning-C, Corning-D glass). Quantitative analysis is made to element contents of samples. Non-destructive testing location and micro-destructive sampling information The portable XRF is used to perform non-destructive analysis and testing of blue pigments used in murals of different eras in Cave 256, including two blue pigment areas in the bottom layer, one dark blue pigment and two blue pigment areas in the surface layer, and blue pigments used in statues repaired in the Qing Dynasty. Moreover, four blue pigment trace samples were obtained taking the pXRF test results as a reference. Table 1 and Figure 2 for details of non-destructive testing location and micro-destructive sampling information. Table 1 pXRF non-destructive testing location and micro-destructive sampling information No. Location and color Dynasty Sample property Analytical methods M256-01 The bottom layer of the damaged part of the north wall of the main room The Five Dynasties Powder pXRF, XRD and PLM M256-02 The bottom layer of the damaged part of the east wall of the main room The Five Dynasties — pXRF M256-03 The third person's ears from the west on the south wall of the tunnel Song Dynasty Powder + block pXRF and XRD µ-FTIR and PLM M256-04 The third person's costume from the west on the south wall of the Song Dynasty Powder pXRF and XRD tunnel M256-05 Head halo of Thousand-Buddha on the east wall of the main room Song Dynasty — pXRF M256-06 Left knee of the main statue in the main room Qing Dynasty Powder pXRF, XRD, FTIR, PLM and ED-XRF Note: “—” means that no sampling Results XRF fluorescence spectrum analysis XRF analysis results show that the two blue pigments used in murals of the Five Dynasties of Cave 256 mainly contain Fe and Ca (Figure 3a). It is supposed that Lazurite pigment may have been used. In murals of the Song Dynasty, the dark blue is similar in composition to the blue pigments, mainly containing Cu and a small amount of Fe and Ca (Figure 3b). The color rendering component may be copper-containing Azurite. The blue pigments in the statue of the Qing Dynasty mainly contain Pb, Fe, and Co (Figure 3c), which are possibly cobalt-containing compounds. XRD phase analysis The XRD phase analysis results of the trace samples are shown in Table 2 and Figure 4 . The result shows that the blue pigments used in the Five Dynasties have strong diffraction peaks when 2θ is 23.999, 19.393 and 13.694, and corresponding d values are 3.704, 4.571 and 6.441, which is consistent with characteristics of diffraction peak of Lazurite. Other phases include talc, calcite, and quartz, all of which come from the white background layer of the mural. The dark blue pigment used in the Song Dynasty has strong diffraction peaks when 2θ is 25.193, 17.033, 24.240, and the corresponding d values are 3.534, 5.181, and 3.675, which are consistent with the characteristic of diffraction peaks of azurite. It also has strong diffraction peaks when 2θ is 16.223, 17.697 and 32.375 and the corresponding d values are 5.480, 5.018, and 2.771, which are consistent with the characteristic diffraction peaks of atacamite. Other phases include small amounts of quartz and calcite. The dark blue pigment is the result of joint use of azurite and atacamite. However, it is still uncertain whether these two pigments are used separately or mixed with each other. The color rendering component of the blue pigment used in the Song Dynasty is only azurite. Other phases include talc, calcite, quartz, and mica from the background layer. The XRD pattern of statues repainted in the Qing Dynasty shows a dispersive peak, and the color rendering component was amorphous, which cannot be determined for the time being. Table 2 XRD phase analysis results of trace samples in Cave 256 Serial number M256-01 M256-03 M256-04 Lazurite (17-0749) Azurite (11-0682) Atacamite (25-0269) 2-Theta d I/I 0 2-Theta d I/I 0 2-Theta d I/I 0 2-Theta d I/I 0 2-Theta d I/I 0 2-Theta d I/I 0 1 9.420 9.361 51 16.223 5.480 54 8.727 10.131 75 13.761 6.430 40 17.204 5.150 55 16.161 5.480 100 2 10.590 8.465 18 17.033 5.181 77 9.337 9.418 64 18.239 4.860 6 17.443 5.080 30 17.618 5.030 70 3 13.694 6.441 11 17.697 5.018 36 16.137 5.493 42 19.537 4.540 18 17.760 4.990 11 21.928 4.050 12 4 17.480 5.0755 11 24.240 3.675 99 17.133 5.176 56 23.966 3.71 100 24.205 3.674 50 31.520 2.836 50 5 18.953 4.682 15 25.193 3.534 79 20.860 4.263 42 24.992 3.56 6 25.310 3.516 100 32.184 2.779 50 6 19.393 4.571 12 26.667 3.343 33 21.077 4.212 40 25.955 3.430 6 28.709 3.107 11 32.424 2.759 55 7 23.999 3.704 11 28.660 3.112 34 24.067 3.693 51 27.769 3.21 16 34.604 2.590 11 32.630 2.742 25 8 26.623 3.346 15 30.957 2.886 36 25.150 3.534 41 29.454 3.030 6 35.307 2.540 25 33.014 2.711 20 9 28.530 3.123 100 32.375 2.771 47 26.493 3.368 59 31.115 2.872 45 35.553 2.523 20 33.915 2.641 14 10 29.440 3.030 53 34.597 2.595 30 28.443 3.127 69 32.472 2.755 4 35.743 2.510 35 35.524 2.525 14 11 30.957 2.886 16 35.244 2.543 34 29.440 3.037 71 34.168 2.622 80 35.846 2.503 30 35.670 2.515 40 12 36.070 2.490 14 35.680 2.512 38 30.913 2.891 31 37.009 2.427 16 38.506 2.336 17 39.527 2.278 70 13 39.450 2.281 12 38.453 2.341 100 32.343 2.766 37 39.636 2.272 25 39.151 2.299 13 39.763 2.265 45 14 43.307 2.093 18 39.147 2.301 55 39.407 2.287 39 42.173 2.141 35 39.365 2.287 35 41.029 2.198 17 15 44.520 2.033 12 39.840 2.265 62 39.753 2.266 44 51.222 1.782 30 39.763 2.265 25 42.401 2.130 25 16 47.597 1.190 15 40.533 2.227 42 43.133 2.095 35 57.322 1.606 20 40.528 2.224 70 44.300 2.043 17 17 48.723 1.872 20 46.557 1.948 43 44.867 20.020 33 59.219 1.559 10 41.623 2.168 15 49.960 1.824 35 18 57.433 1.604 9 49.980 1.824 40 47.467 1.917 43 61.164 1.514 10 46.584 1.948 20 50.166 1.817 25 19 60.727 1.525 8 57.780 1.595 30 48.507 1.675 44 62.963 1.475 14 49.960 1.824 17 53.310 1.717 20 20 64.887 1.437 11 64.757 1.438 30 49.937 1.827 100 68.423 1.370 18 57.743 1.595 15 57.322 1.606 55 Microscopic FTIR spectroscopy analysis Microscopic FTIR spectroscopy is used to study the dark blue pigment samples of the donor’s streamers on the south wall of the tunnel. Under the microscope, it can be seen that there are blue and green pigment particles distributed. These two kinds of particles are analyzed separately, and the results are shown in Figure 5a. The blue pigment particles have absorption peaks at 3427cm −1 , 1463cm −1 , 1408cm −1 , 1090cm −1 , 948cm −1 , 837cm −1 and 767cm −1 , which are very close to the peak positions of azurite in the literature. The green pigment particles have absorption peaks at 3441cm −1 , 3346cm −1 , 983cm −1 , 951cm −1 , 927cm −1 , and 837cm −1 , which are close to the peak position of atacamite[ 13 ] and is consistent with the XRD results. Figure 5b shows the infrared spectrum of blue pigments used in statue repainted in the Qing Dynasty. There are absorption peaks at 3309cm −1 , 1652cm −1 , 1534cm −1 , 1053cm −1 , 795cm −1 , and 593cm −1 , which are very similar to smalt [ 14 , 15 ]. Microscopic analysis The blue pigment used in the Five Dynasties shows a very uniform bright blue under single polarized light, with different particle sizes, and is completely extinct under orthogonal polarized light, which is consistent with the XRD analysis result, and so it is lazurite mineral (Figure 6 a and 6 b). There are blue and green particles in the dark blue pigment used in the Song Dynasty. Under single polarized light, the blue pigment particles are of different sizes. Large particles are dark blue and small particles are light blue. Blue particles mostly extinct under orthogonal polarized light and should be azurite. Under single polarized light, the green pigment particles are in the form of massive rocks, which should be natural atacamite (Figure 6 c and 6 d). Blue pigment used in the Qing Dynasty looks like sharp-edged glass shards under single-polarized light, varying from light blue to dark blue. They are completely extinct under cross-polarized light, with a refractive index of 1.55, which are identified as smalt (Figure 6 e and 6 f). In order to make out whether azurite and atacamite in the dark blue pigment are used separately or mixed with each other, the M256-03 dark blue block sample is embedded with resin. A polishing machine is used to polish the surface of the sample until there are no obvious scratches, and then observe it under a microscope. The result shows that green atacamite and blue azurite particles mixed with each other and the azurite particles are obviously more than the atacamite particles. It can be determined that the dark blue pigment used in the Song Dynasty is the mixture of green pigment and blue pigment (Figure 7). Quantitative analysis of micro-area X-ray fluorescence spectrometer The micro-area X-ray fluorescence spectrometer is used for quantitative analysis of smalt pigment used in the Qing Dynasty. The result shows that the percentage of oxides in smalt pigment is: SiO 2 : 72.13%, K 2 O: 15.90%, CaO: 5.03%, Fe 2 O 3 : 2.83%, CoO: 1.26%, NiO: 0.23%, and PbO: 2.62. Discussion Based on the results of XRF, XRD, M-FTIR and PLM analysis, the blue pigments used in the murals and statues of Cave 256 at different periods are different. Natural lazurite minerals were used as blue pigment in the Five Dynasties. Azurite was used as blue pigment in murals of the Song Dynasty. People also used the mixture of azurite and atacamite as dark blue. Smalt was used as the blue pigment in the Qing Dynasty. In the 3rd century AD, the lazurite pigment was introduced into the Western Regions from Afghanistan through the Silk Road, and then to the Central Plains through the Hexi Corridor[ 16 ]. Mr. Su believes that lazurite was used as a pigment from the Jin Dynasties (265-420 AD). Since then, lazurite pigments have been found in major grottoes in the northern region[ 17 – 19 ]. A large number of lazurite were also used in the early Dunhuang murals. However, it gradually decreased after the 7th century, and the use of azurite gradually increased. Azurite has already occupied a dominant position in Dunhuang murals of the Tang Dynasty, which might be related to the discovery of azurite in the Qilian Mountains of Gansu in the Tang Dynasty[ 20 ]. Cave 256 of Mogao Grottoes was built in the Five Dynasties. Azurite was used as the blue pigment in most caves at that time. However, expensive lazurite was used in Cave 256. The repainting period of murals on the surface layer was about 60 years later than the excavation of Cave 256. Azurite used here instead of lazurite. There are two main reasons for this difference. Firstly, Cave 256 was the merit cave of Cao Yuanshen, the third military governor of Guiyi Army (a local armed regime that originated from the Tang Dynasty). During this period, the regime of Guiyi Army was stable and the economy developed rapidly. As the supreme ruler at the time, Cao Yuanshen had sufficient funding support to build caves and paint. The repainted cave belonged to Murong Yanchang, the military director of Yumen Town of the Guiyi Army, and his wife Yan in the Song Dynasty during the Cao Zongshou period. At this time, the Guiyi army regime began to go downhill. The Ganzhou Uighurs and Gaochang Uighurs continued to invade, and internal contradictions were numerous. As a result, they were short of money. They only afforded repainting an old cave because it cost too much to open a new one. Moreover, the cheaper azurite was used in a large area. Secondly, due to the unobstructed Silk Road, flourishing trade and the prosperity of the pigment market during the Cao Yuanshen period, lazurite was also relatively easy to obtain as an imported pigment. In the Cao Zongshou period (after the 11th century), frequent battles in the Hexi Corridor, traffic obstruction and social restlessness affected the source of pigments used in Dunhuang murals[ 21 ]. Smalt is a glassy pigment that develops color with cobalt element. It has been industrialized in Europe since the 15th century and it has been widely used in European oil paintings and church murals[ 22 – 27 ]. In the 19th century, it was gradually replaced by other inexpensive artificial blue pigments. The usage of smalt pigment in China mostly occurred in the Qing Dynasty. The earliest evidence at present is the land-and-water drawing of Luochuan, Shaanxi painted in the thirtieth year of Kangxi (1691AD) [ 28 ]. This pigment is concentrated in Beijing and Shanxi and scattered in other areas [ 29 – 31 ]. The forms of cultural relics are mainly architectural murals, colored paintings and statues. The smalt pigment used in statue of the Qing Dynasty in Cave 256 is reported for the first time in the murals and statues of Mogao Grottoes. Oxide percentages of the smalt pigment used in colored paintings founded in Beijing, Shanxi, Inner Mongolia and Sichuan, blue and white porcelains of the Yuan Dynasty and the Ming Dynasty, Greek murals and European oil paintings are listed in Table 3 . It can be seen that the oxide content of smalt pigment used in China was close to that of European murals and oil paintings: they all contained about 70% SiO 2 , the content of K 2 O generally exceeded 10%, and the content of the color rendering element Co was 1%-5%. In addition, they also contained Fe, Ca, Ni, As, Pb and other elements. The smalt pigment found in Cave 256 is also one of this type of material. However, as for the smalt pigment used in blue and white porcelains of the Yuan Dynasty and the Ming Dynasty, the content of SiO 2 was close, K 2 O was relatively low, Al 2 O 3 was about 15% and the content of the color rendering element Co was generally lower than 0.5%. In summary, the smalt pigment used in statue of Cave 256 should be imported from Europe. In this study, the smalt pigment is firstly founded in statues of the Qing Dynasty in Mogao Grottoes in Dunhuang. According to previous literature, artificial ultramarine pigments were generally used for remodeling and repainting of statues of Mogao Grottoes during the Qing Dynasty. The smalt pigment discovered this time can be used as a reference for us to study the history of repainting and repairing of statues in Cave 256. The smalt pigment was a very important blue paint in the history of European art. It was regarded as the only artificial substitute for azurite and Lazurite until the invention of artificial ultramarine. There is evidence that the export of smalt pigment from Europe to China covered almost the entire 18th century and continued into the 19th century[ 34 , 35 ]. After the mid-19th century, artificial ultramarine entered China. With low price and strong hiding power, it quickly replaced smalt. Kangxi actively explored the Western Regions in his later years. Taking this as a chance, he began to manage the area west of Jiayuguan. During the 5th-6th year of Yongzheng, 2405 households, about 10,000 people, immigrated to Dunhuang. The arrival of immigrants laid the foundation for the development of Dunhuang in the Qing Dynasty and even in modern times[ 36 ]. According to Inscriptions for Donors of Mogao Grottoes in Dunhuang (Cave 454), the pedagogue Lei Jixiang completed his donation on February 15th of the lunar calendar in the first year of Yongzheng[ 37 ]. It can be concluded that the first year of Yongzheng (1723 AD) should be the earliest date for the reconstruction of the Mogao Grottoes in the Qing Dynasty. Based on the history of the introduction of smalt into China and the history of the reconstruction of Mogao Grottoes in the Qing Dynasty, it is believed that the statues of Cave 256 were rebuilt in the first half of the 19th century, that is, during the reign of Jiaqing and Daoguang in the Qing Dynasty. Table 3 Comparison of element content of smalt pigment in different regions[ 28 ][ 32 , 33 ] Source Oxide percentage (Wt%) Na 2 O Al 2 O 3 SiO 2 K 2 O CaO Fe 2 O 3 MnO C O O NiO CuO MgO BaO As 2 O 3 PbO Cave 256 of Mogao Grottoes 72.13 15.90 5.03 2.83 1.26 0.23 2.62 Cining Palace, Forbidden City, Beijing 0.18 1.27 72.90 10.35 0.53 0.62 2.35 5.24 6.54 Chengqing Palace, Xiannong Temple, Beijing 0.19 1.50 73.32 8.64 0.84 0.49 1.03 4.60 Jingxin Temple, Taigu, Shanxi 0.47 0.67 66.41 11.99 0.25 2.99 3.15 0.08 12.46 1.22 Sanqing Palace, Shanxi 0.16 0.53 73.00 11.41 2.79 3.40 0.12 0.02 0.09 8.36 Qianfo Cliff, Guangyuan, Sichuan 0.25 0.33 80.67 8.44 0.04 3.59 3.90 0.47 0.08 2.30 Dazhao Temple, Inner Mongolia 0.91 0.12 77.63 13.82 1.77 1.00 0.77 3.89 Cobalt of blue and white porcelain of the Yuan Dynasty 3.14 15.22 68.05 2.74 8.78 1.73 0.09 0.37 0.39 Cobalt of blue and white porcelain of the Yuan Dynasty 2.68 14.79 66.76 4.39 6.98 2.83 0.11 0.47 0.36 Cobalt of blue and white porcelain of the early Ming Dynasty 2.84 15.35 68.94 3.16 5.98 2.17 0.25 0.24 Greece murals 68.93 22.59 2.16 2.49 4.09 European oil painting 66-72 10-21 2-18 Conclusion Pigment is an indispensable and the most important material in the process of making murals and statues. Pigments used in murals and statues in different historical periods of Mogao Grottoes are also different because of factors such as the origin of the pigments, processing techniques, prices, etc. In this paper, blue pigments used in murals and statues of the Five Dynasties, the Song Dynasty and the Qing Dynasty of Cave 256 are studies. The result shows that expensive lazurite pigment was used in the murals of the Five Dynasties and azurite was used on a large scale in the repainted murals of the Song Dynasties, which was closely related to the social status of the cave owner and the historical background at that time. The blue pigment in the repainted statues of the Qing Dynasty was smalt, which was first discovered in the Mogao Grottoes. It is judged that it is an imported pigment from Europe based on the element composition. Based on the history of the reconstruction of Mogao Grottoes in the Qing Dynasty, it is believed that the statues of Cave 256 were rebuilt in the first half of the 19th century, that is, during the reign of Jiaqing and Daoguang in the Qing Dynasty. In summary, the analysis and research of pigments in a specific historical period can reflect the social development at that time on the one hand, and on the other hand can provide scientific evidence for us to analyze the reconstruction and repainting history of the murals and statues of Mogao Grottoes. Abbreviations pXRF portable X-ray fluorescence µ-FTIR microscopic flourier transformed infrared spectroscopy XRD X-ray diffraction PLM polarizing microscope ED-XRF energy dispersive X-ray fluorescence. Declarations Availability of data and materials All data generated or analyzed during this study are included in this published article. Competing interests The authors declare that they have no competing interests. Funding This research is supported by the Local Project Guided by the Central Government of Gansu Province, Science and Technology Project of Gansu Province (Grant No. 21JR7RA759) and Joint Fund for Regional Innovation and Development of National Natural Science Foundation of China(U21A20282). Authors’ contributions BMS and MLS provided support and guidance for this study. BWS and ZRY performed XRD, PLM and performed the analysis. QC, ZYY performed XRF and prepared the manuscript. ZW performed M-FTIR and prepared the manuscript. All authors read and approved the final manuscript. Acknowledgements The authors would like to acknowledge Dr. Li Na at the National Museum of China，for her guidance and expertise. Authors would like to thank the peer reviewers and editors for providing valuable feedback. References Chen GQ. Study on Salting Damage Analysis and Treatment of Wall Paintings at Mogao Grottoes, Dunhuang. Lanzhou: Lanzhou University, 2016: 1-4 (in Chinese). Dunhuang Academy. 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Chinese Grottoes: Anxi Yulin Grottoes. Beijing: Cultural Relics Press, 2012 (in Chinese). Corregidor V, Oliveira AR, Rodrigues PA, Alves LC. Paintings on copper by the Flemish artist Frans Francken Ⅱ: PIXE characterization by external microbeam. Nuclear Instruments and Methods in Physics Research Section B: Beam Interactions with Materials and Atoms, 2015(1): 291-295. Kalinina KB, Bonaduce I, Colombini MP, Artemieva IS. An analytical investigation of the painting technique of Italian Renaissance master Lorenzo Lotto. Journal of Cultural Heritage, 2012(3): 259-274. Rebollo E, Nodari L, Russo U, Bertoncello R, Scardellato C, Romano F, Ratti F, Poletto L. Non-invasive multitechnique methodology applied to the study of two 14th century canvases by Lorenzo Veneziano. Journal of Cultural Heritage, 2013(3): 153-160. Civici N. Non-destruction identification of inorganic pigments used in 16-17th century Albanian icons by total reflection X-ray fluorescence analysis. Journal of Cultural Heritage, 2006(4): 339-343. Daniilia S, Minopoulou E, Andrikopoulos KS, Tsakalof A, Bairachtari K. From Byzantine to post-Byzantine art: the painting technique of St Stephen`s wall paintings at Meteora, Greece. Journal of Archaeological Science. 2008(6): 1695-1707. Bianchin S, Favaro M, Vigato PA, Botticelli G, Germani G, Botticelli S. The scientific approach to the restoration and monitoring of mural paintings at S. Girolamo Chapel-SS. Annunziata Church in Florences. Journal of Cultural Heritage, 2009(3): 379-387. Hui N. Analysis and Research on Smalt Pigment in the Ming Dynasty and Qing Dynasty of China. Xi’an: Northwest University, 2015: 18-21. Lei Y, Qu L, Cheng XL, Yang H, Wang SW. The Discovery of Smalt in Jianfu Palace in Forbidden City. Wenbo, 2009 (6): 276-279 (in Chinese). Xu N. Analysis of the Production Technology of the Painted statues at Qinglian Temple in Jincheng, Shanxi and a Preliminary Study on its Virtual Restoration. Xi’an: Northwest University, 2014 (in Chinese). Liu MY and Lei YX. A Preliminary Exploration of Colored Drawings on Rafters in Wanfo Hall of Zhenguo Temple, Pingyao County, Shanxi Province. Architectural History, 2012 (3): 36-54(in Chinese). Du F. Two Different Imported Smalt Pigments: (“Samarra” and “Sumatra”). Science in China (Series E). Technical Science, 2007 (5): 636-643 (in Chinese). Riedrerer J. Die Smalte Sammelmappe - DEUTSCHE- ZEITSCHRIFT. Wissenschaftliche Verlagsgesellschaft, 1968(9): 386-395. Giannini R, Freestone IC, Shortland AJ. European cobalt sources identified in the production of Chinese famille rose porcelain. Journal of Archaeological Science, 2017(80): 27-36. Liu MY. Research on Pigments for Decorative Polychrome Painting in Official Handicraft Regulations and Precedents of Qing Dynasty. Beijing, Tsinghua University, 2019: 318 (in Chinese). Chen GW. Study on Dunhuang Population Issues in Qing Dynasty. Journal of Dunhuang Studies, 2018 (1): 55-67 (in Chinese). Dunhuang Academy. Inscriptions for Donors of Mogao Grottoes in Dunhuang. Beijing: Cultural Relics Press, 1986 (in Chinese). Cite Share Download PDF Status: Under Review Version 1 posted Reviews received at journal 29 Jan, 2022 Reviewers invited by journal 28 Jan, 2022 Editor assigned by journal 27 Jan, 2022 First submitted to journal 26 Jan, 2022 You are reading this latest preprint version Research Square lets you share your work early, gain feedback from the community, and start making changes to your manuscript prior to peer review in a journal. As a division of Research Square Company, we’re committed to making research communication faster, fairer, and more useful. We do this by developing innovative software and high quality services for the global research community. Our growing team is made up of researchers and industry professionals working together to solve the most critical problems facing scientific publishing. Also discoverable on Platform About Our Team In Review Editorial Policies Advisory Board Help Center Resources Author Services Accessibility API Access RSS feed Manage Cookie Preferences © Research Square 2026 | ISSN 2693-5015 (online) Privacy Policy Terms of Service Do Not Sell My Personal Information {"props":{"pageProps":{"initialData":{"identity":"rs-1266982","acceptedTermsAndConditions":true,"allowDirectSubmit":false,"archivedVersions":[],"articleType":"Research Article","associatedPublications":[],"authors":[{"id":80019503,"identity":"447d51a4-df02-46b1-b2e4-2bea86e8ff1f","order_by":0,"name":"Bi Wen Shui","email":"data:image/png;base64,iVBORw0KGgoAAAANSUhEUgAAAZAAAAAyAQMAAABI0h/eAAAABlBMVEX///8AAABVwtN+AAAACXBIWXMAAA7EAAAOxAGVKw4bAAAAw0lEQVRIiWNgGAWjYDACCQaGwwwGQAZ7Y+ODD6Rp4TncbDiDWC3MEEZ6mzQHMTrkZ/cYHi4oOCxnLvmwQZqBwU5Ot4GAFoM7ZwwOzzA4bGw5O7HBuIAh2djsACEtEjkGh3kMbiduuJ3YkDyD4UDiNkJa5GdAtNRvuHmw4TAPMVoYbkC0JBjcYGxsJkqLwY20AqBf/htuOJPYzDjDgAi/yM9I3vy54E+avMHx489/fKiwkyOoBd1S0pSPglEwCkbBKMABAMrlR2iifWDJAAAAAElFTkSuQmCC","orcid":"https://orcid.org/0000-0002-7077-9246","institution":"Northwest University","correspondingAuthor":true,"prefix":"","firstName":"Bi","middleName":"Wen","lastName":"Shui","suffix":""},{"id":80019504,"identity":"ff7f3abd-2868-4341-9ed7-e03a6bf63e26","order_by":1,"name":"Zong Ren Yu","email":"","orcid":"","institution":"Dunhuang Research Academy","correspondingAuthor":false,"prefix":"","firstName":"Zong","middleName":"Ren","lastName":"Yu","suffix":""},{"id":80019505,"identity":"e05f7c95-236b-4d81-82c5-3b26abe7ce7c","order_by":2,"name":"Qiang Cui","email":"","orcid":"","institution":"Dunhuang Research Academy","correspondingAuthor":false,"prefix":"","firstName":"Qiang","middleName":"","lastName":"Cui","suffix":""},{"id":80019506,"identity":"543655fb-4a94-49bd-988e-144b5c25f1a0","order_by":3,"name":"Zhuo Wang","email":"","orcid":"","institution":"Dunhuang Research Academy","correspondingAuthor":false,"prefix":"","firstName":"Zhuo","middleName":"","lastName":"Wang","suffix":""},{"id":80019507,"identity":"d570a2bd-8ea1-4a3c-8f39-6395fb2674bc","order_by":4,"name":"Zhi yuan Yin","email":"","orcid":"","institution":"Dunhuang Research Academy","correspondingAuthor":false,"prefix":"","firstName":"Zhi","middleName":"yuan","lastName":"Yin","suffix":""},{"id":80019508,"identity":"8f35a87f-1300-4217-875b-8fb7104f04c6","order_by":5,"name":"Man Li Sun","email":"","orcid":"","institution":"Northwest University","correspondingAuthor":false,"prefix":"","firstName":"Man","middleName":"Li","lastName":"Sun","suffix":""},{"id":80019509,"identity":"ddea3af1-4280-4561-a4a7-a1e31b5557b1","order_by":6,"name":"Bo Ming Su","email":"","orcid":"","institution":"Dunhuang Research Academy","correspondingAuthor":false,"prefix":"","firstName":"Bo","middleName":"Ming","lastName":"Su","suffix":""}],"badges":[],"createdAt":"2022-01-17 02:50:17","currentVersionCode":1,"declarations":"","doi":"10.21203/rs.3.rs-1266982/v1","doiUrl":"https://doi.org/10.21203/rs.3.rs-1266982/v1","draftVersion":[],"editorialEvents":[],"editorialNote":"","failedWorkflow":false,"files":[{"id":17823698,"identity":"5603d225-b015-4b5a-987c-a32cdaa7dbc9","added_by":"auto","created_at":"2022-01-31 19:57:02","extension":"png","order_by":1,"title":"Figure 1","display":"","copyAsset":false,"role":"figure","size":857973,"visible":true,"origin":"","legend":"\u003cp\u003eLocation of Cave 256\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig1.png","url":"https://assets-eu.researchsquare.com/files/rs-1266982/v1/4551b4c16575c0a51acef3af.png"},{"id":17823914,"identity":"09f84c16-780a-44c8-90b1-0bfb6c9b80dc","added_by":"auto","created_at":"2022-01-31 20:00:02","extension":"png","order_by":2,"title":"Figure 2","display":"","copyAsset":false,"role":"figure","size":993297,"visible":true,"origin":"","legend":"\u003cp\u003epXRF testing and micro-sampling location of Cave 256\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig2.png","url":"https://assets-eu.researchsquare.com/files/rs-1266982/v1/e28eaf77c0f2ebce152ea90e.png"},{"id":17823700,"identity":"4687df68-843c-4adc-8e60-efad4b8d2c90","added_by":"auto","created_at":"2022-01-31 19:57:02","extension":"png","order_by":3,"title":"Figure 3","display":"","copyAsset":false,"role":"figure","size":170276,"visible":true,"origin":"","legend":"\u003cp\u003eXRF patterns of blue pigments used in different dynasties in Cave 256\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig3.png","url":"https://assets-eu.researchsquare.com/files/rs-1266982/v1/c3b1a988c71d0c99895e56f4.png"},{"id":17823915,"identity":"b4461461-0b04-41b2-b93f-03aad328afa4","added_by":"auto","created_at":"2022-01-31 20:00:02","extension":"png","order_by":4,"title":"Figure 4","display":"","copyAsset":false,"role":"figure","size":115644,"visible":true,"origin":"","legend":"\u003cp\u003eXRD patterns of blue pigments used in different dynasties in Cave 256\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig4.png","url":"https://assets-eu.researchsquare.com/files/rs-1266982/v1/88c1001263d722e6192a7ca7.png"},{"id":17823917,"identity":"f87f2e34-3134-49ac-b30e-28ef84b398d9","added_by":"auto","created_at":"2022-01-31 20:00:02","extension":"png","order_by":5,"title":"Figure 5","display":"","copyAsset":false,"role":"figure","size":127625,"visible":true,"origin":"","legend":"\u003cp\u003eInfrared spectrum of blue pigment used in Cave 256\u003c/p\u003e","description":"","filename":"Fig5.png","url":"https://assets-eu.researchsquare.com/files/rs-1266982/v1/ed449465ef0d9f1abcc8f704.png"},{"id":17824224,"identity":"537d1a73-84f6-418e-b1c7-00fde519f646","added_by":"auto","created_at":"2022-01-31 20:03:02","extension":"png","order_by":6,"title":"Figure 6","display":"","copyAsset":false,"role":"figure","size":2158832,"visible":true,"origin":"","legend":"\u003cp\u003ePolarized microscope photos of blue pigments used in different dynasties in Cave 256\u003c/p\u003e\u003cp\u003e(a and b: blue pigment used in the Five Dynasties; c and d: dark blue pigment used in the Song Dynasty; e and f: blue pigment used in the statue in the Qing Dynasty)\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig6.png","url":"https://assets-eu.researchsquare.com/files/rs-1266982/v1/29ccc2bf5610bb2622c5dee0.png"},{"id":17823703,"identity":"19dd9c53-6507-4e4f-b63d-fbb37d7cb60b","added_by":"auto","created_at":"2022-01-31 19:57:02","extension":"png","order_by":7,"title":"Figure 7","display":"","copyAsset":false,"role":"figure","size":2785927,"visible":true,"origin":"","legend":"\u003cp\u003eCross-section photos of dark blue pigment used in the Song Dynasty in Cave 256\u003c/p\u003e\u003cp\u003e\u003cbr\u003e\u003c/p\u003e","description":"","filename":"Fig7.png","url":"https://assets-eu.researchsquare.com/files/rs-1266982/v1/8034b8e4b95158f82fa94aeb.png"},{"id":17824226,"identity":"08211431-f6b9-4821-bdf4-df7ba8179330","added_by":"auto","created_at":"2022-01-31 20:03:05","extension":"pdf","order_by":0,"title":"","display":"","copyAsset":false,"role":"manuscript-pdf","size":641070,"visible":true,"origin":"","legend":"","description":"","filename":"manuscript.pdf","url":"https://assets-eu.researchsquare.com/files/rs-1266982/v1/f2e6c981-0be3-4028-8e0e-2879e3cff941.pdf"}],"financialInterests":"","formattedTitle":"Study on blue pigments in Cave 256, Mogao Grottoes: Five dynasties, Song Dynasty and Qing Dynasty","fulltext":[{"header":"Introduction","content":"\u003cp\u003eDunhuang Mogao Grottoes is located 24 kilometers southeast of present-day Dunhuang City. As a comprehensive art combining architecture, sculpture and mural painting, it is the largest, longest lasting and the most informative site of grottoes temples in China and the whole world. Construction of Mogao Grottoes lasted for almost a thousand years from the second half of the 4th century to the 14th century. There was no new cave were excavated after the Ming Dynasty. A large number of murals and statues were repainted in the Qing Dynasty. There are about 45,000m\u003csup\u003e2\u003c/sup\u003e of murals and over 2,200 statues in Mogao Grottoes[\u003cspan citationid=\"CR1\" class=\"CitationRef\"\u003e1\u003c/span\u003e], which are important physical materials for studying the history of materials and craftsmanship of ancient Chinese murals and statues.\u003c/p\u003e \u003cp\u003eCave 256 is located on the second floor of the central area of the southern area of Dunhuang Mogao Grottoes, about 200 meters north of the nine storeys pagoda of Mogao Grottoes(Fig.\u0026nbsp;\u003cspan refid=\"Fig1\" class=\"InternalRef\"\u003e1\u003c/span\u003e). It has a relatively large area, with over 500m\u003csup\u003e2\u003c/sup\u003e of murals and 7 statues[\u003cspan citationid=\"CR2\" class=\"CitationRef\"\u003e2\u003c/span\u003e]. According to scholars, Cave 256 was built by Cao Yuanshen, the third military governor of Guiyi Army (a local armed regime that originated from the Tang Dynasty). It was founded in the Five Dynasties[\u003cspan citationid=\"CR3\" class=\"CitationRef\"\u003e3\u003c/span\u003e] and repaired during the Zhenzong period of the Northern Song Dynasty by Murong Yanchang, the military director of Yu Men Town of the Guiyi Army, and his wife Yan. The bottom layer was covered and a new layer of murals was painted[\u003cspan additionalcitationids=\"CR5\" citationid=\"CR4\" class=\"CitationRef\"\u003e4\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR6\" class=\"CitationRef\"\u003e6\u003c/span\u003e]. Statues were repaired and repainted in the Qing Dynasty.\u003c/p\u003e\u003cp\u003eBlue is highly regarded in ancient Chinese culture[\u003cspan citationid=\"CR7\" class=\"CitationRef\"\u003e7\u003c/span\u003e]. As one of the three primary colors, it is the most basic color in painting. It symbolizes eternity, nobility and purity and is loved by people in different times. It is also one of the most important colors of murals in the Mogao Grottoes. Based on previous research results, blue pigments used in murals and statues of the Mogao Grottoes are Lazurite[\u003cspan citationid=\"CR8\" class=\"CitationRef\"\u003e8\u003c/span\u003e, \u003cspan citationid=\"CR9\" class=\"CitationRef\"\u003e9\u003c/span\u003e] (from the Sixteen Kingdoms to the Northern Zhou Dynasty), Azurite[\u003cspan citationid=\"CR10\" class=\"CitationRef\"\u003e10\u003c/span\u003e] (the Sui Dynasty to the Five Dynasties), indigo blue[\u003cspan citationid=\"CR11\" class=\"CitationRef\"\u003e11\u003c/span\u003e] found in individual caves and artificial ultramarine used in repainting in Qing Dynasty[\u003cspan citationid=\"CR12\" class=\"CitationRef\"\u003e12\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eIn this study, scientific analysis methods are used to study types, usage techniques and sources of different blue pigments used in murals and statues of Cave 256 in the Five Dynasties, the Song Dynasty and the Qing Dynasty, providing new ideas for analysis of history of blue pigments used in the Mogao Grottoes.\u003c/p\u003e"},{"header":"Materials And Methods","content":"\u003cdiv id=\"Sec3\" class=\"Section2\"\u003e \u003ch2\u003eAnalysis equipment and parameters\u003c/h2\u003e \u003cp\u003e(1) Portable X-ray fluorescence analyzer\u003c/p\u003e \u003cp\u003eThe Thermo XL3t-800 Portable X-ray fluorescence analyzer is used for element analysis of pigments. It uses silver target. The spot diameter is 1cm. The analysis condition is 50kV/40\u0026micro;A (maximum), the detection time is 1min, and the soil mode is used.\u003c/p\u003e \u003cp\u003e(2) Digital microscope\u003c/p\u003e \u003cp\u003eVHX-600E digital microscopes manufactured by KEYENCE are used. Microscope lens model is VH-Z20R (20X-200X). VHX-600E built-in floodlight is used for observation.\u003c/p\u003e \u003cp\u003e(3) X-ray diffraction analyzer\u003c/p\u003e \u003cp\u003eThe Rigaku Dmax/2500X X-ray diffraction analyzer is used for phase analysis of pigments. It has copper target. The analysis voltage is 40kV and the current is 100mA. Scanning is continuous. The scanning range is 5\u0026deg;-70\u0026deg;. Graphite monochromator is used for filtering.\u003c/p\u003e \u003cp\u003e(4) Microscopic FTIR spectroscopy\u003c/p\u003e \u003cp\u003eThe Thermo Scientific Nicolet iN10 MX Microscopic FTIR spectroscopy is equipped with liquid nitrogen cooled MCT/A detector and has transmission mode. The measuring range is 4000-675cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, and the spectral resolution is 4cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, with 128-time scanning.\u003c/p\u003e \u003cp\u003e(5) Polarizing microscope\u003c/p\u003e \u003cp\u003eDM2700P polarizing microscope (Lycra, Germany) is equipped with DMC2900 camera (magnification 50\u0026times;, 100\u0026times;, 200\u0026times;, 500\u0026times; and 1000\u0026times;).\u003c/p\u003e \u003cp\u003e(6) Micro-area X-ray fluorescence spectrometer\u003c/p\u003e \u003cp\u003eAs for German Bruker ARTAX-400 mobile micro-area X-ray fluorescence spectrometer, input voltage is 30KV, input current is 900\u0026micro;A, test time is 300s, X-ray tube uses Mo target with fine focal spot and helium gas environment is used for test. The analysis and test results are compared with the standard working curve fitted by glass standard samples (Corning-B, Corning-C, Corning-D glass). Quantitative analysis is made to element contents of samples.\u003c/p\u003e \u003c/div\u003e \u003cdiv id=\"Sec4\" class=\"Section2\"\u003e \u003ch2\u003eNon-destructive testing location and micro-destructive sampling information\u003c/h2\u003e \u003cp\u003eThe portable XRF is used to perform non-destructive analysis and testing of blue pigments used in murals of different eras in Cave 256, including two blue pigment areas in the bottom layer, one dark blue pigment and two blue pigment areas in the surface layer, and blue pigments used in statues repaired in the Qing Dynasty. Moreover, four blue pigment trace samples were obtained taking the pXRF test results as a reference. Table \u003cspan refid=\"Tab1\" class=\"InternalRef\"\u003e1\u003c/span\u003e and Figure \u003cspan refid=\"Fig2\" class=\"InternalRef\"\u003e2\u003c/span\u003e for details of non-destructive testing location and micro-destructive sampling information.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab1\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 1\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003epXRF non-destructive testing location and micro-destructive sampling information\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"5\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\"\u003e \u003cp\u003eNo.\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLocation and color\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eDynasty\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSample property\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eAnalytical methods\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM256-01\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThe bottom layer of the damaged part of the north wall of the main room\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eThe Five Dynasties\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePowder\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003epXRF, XRD and PLM\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM256-02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThe bottom layer of the damaged part of the east wall of the main room\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eThe Five Dynasties\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003epXRF\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM256-03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThe third person's ears from the west on the south wall of the tunnel\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSong Dynasty\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePowder + block\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003epXRF and XRD\u003c/p\u003e \u003cp\u003e\u0026micro;-FTIR and PLM\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM256-04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eThe third person's costume from the west on the south wall of the\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSong Dynasty\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePowder\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003epXRF and XRD\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003etunnel\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM256-05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eHead halo of Thousand-Buddha on the east wall of the main room\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eSong Dynasty\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e\u0026mdash;\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003epXRF\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eM256-06\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e \u003cp\u003eLeft knee of the main statue in the main room\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e \u003cp\u003eQing Dynasty\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003ePowder\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003epXRF, XRD, FTIR, PLM and ED-XRF\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003ctfoot\u003e \u003ctr\u003e\u003ctd colspan=\"5\"\u003eNote: \u0026ldquo;\u0026mdash;\u0026rdquo; means that no sampling\u003c/td\u003e\u003c/tr\u003e \u003c/tfoot\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e \u003cp\u003e \u003c/p\u003e \u003c/div\u003e"},{"header":"Results","content":"\u003cdiv class=\"Section2\" id=\"Sec6\"\u003e\n \u003ch2\u003eXRF fluorescence spectrum analysis\u003c/h2\u003e\n \u003cp\u003eXRF analysis results show that the two blue pigments used in murals of the Five Dynasties of Cave 256 mainly contain Fe and Ca (Figure 3a). It is supposed that Lazurite pigment may have been used. In murals of the Song Dynasty, the dark blue is similar in composition to the blue pigments, mainly containing Cu and a small amount of Fe and Ca (Figure 3b). The color rendering component may be copper-containing Azurite. The blue pigments in the statue of the Qing Dynasty mainly contain Pb, Fe, and Co (Figure 3c), which are possibly cobalt-containing compounds.\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec7\"\u003e\n \u003ch2\u003eXRD phase analysis\u003c/h2\u003e\n \u003cp\u003eThe XRD phase analysis results of the trace samples are shown in Table \u003cspan class=\"InternalRef\"\u003e2\u003c/span\u003e and Figure \u003cspan class=\"InternalRef\"\u003e4\u003c/span\u003e. The result shows that the blue pigments used in the Five Dynasties have strong diffraction peaks when 2\u0026theta; is 23.999, 19.393 and 13.694, and corresponding d values are 3.704, 4.571 and 6.441, which is consistent with characteristics of diffraction peak of Lazurite. Other phases include talc, calcite, and quartz, all of which come from the white background layer of the mural. The dark blue pigment used in the Song Dynasty has strong diffraction peaks when 2\u0026theta; is 25.193, 17.033, 24.240, and the corresponding d values are 3.534, 5.181, and 3.675, which are consistent with the characteristic of diffraction peaks of azurite. It also has strong diffraction peaks when 2\u0026theta; is 16.223, 17.697 and 32.375 and the corresponding d values are 5.480, 5.018, and 2.771, which are consistent with the characteristic diffraction peaks of atacamite. Other phases include small amounts of quartz and calcite. The dark blue pigment is the result of joint use of azurite and atacamite. However, it is still uncertain whether these two pigments are used separately or mixed with each other. The color rendering component of the blue pigment used in the Song Dynasty is only azurite. Other phases include talc, calcite, quartz, and mica from the background layer. The XRD pattern of statues repainted in the Qing Dynasty shows a dispersive peak, and the color rendering component was amorphous, which cannot be determined for the time being.\u003c/p\u003e\n \u003cdiv class=\"gridtable\"\u003e\u0026nbsp;\u003ctable border=\"1\" id=\"Tab2\"\u003e\n \u003ccaption language=\"En\"\u003e\n \u003cdiv class=\"CaptionNumber\"\u003eTable 2\u003c/div\u003e\n \u003cdiv class=\"CaptionContent\"\u003e\n \u003cp\u003eXRD phase analysis results of trace samples in Cave 256\u003c/p\u003e\n \u003c/div\u003e\n \u003c/caption\u003e\n \u003ccolgroup cols=\"19\"\u003e\u003c/colgroup\u003e\n \u003cthead\u003e\n \u003ctr\u003e\n \u003cth align=\"left\" rowspan=\"2\"\u003e\n \u003cp\u003eSerial number\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003eM256-01\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003eM256-03\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003eM256-04\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003eLazurite (17-0749)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003eAzurite (11-0682)\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\" colspan=\"3\"\u003e\n \u003cp\u003eAtacamite (25-0269)\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2-Theta\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ed\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eI/I\u003csub\u003e0\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2-Theta\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ed\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eI/I\u003csub\u003e0\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2-Theta\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ed\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eI/I\u003csub\u003e0\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2-Theta\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ed\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eI/I\u003csub\u003e0\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2-Theta\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ed\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eI/I\u003csub\u003e0\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003e2-Theta\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003ed\u003c/p\u003e\n \u003c/th\u003e\n \u003cth align=\"left\"\u003e\n \u003cp\u003eI/I\u003csub\u003e0\u003c/sub\u003e\u003c/p\u003e\n \u003c/th\u003e\n \u003c/tr\u003e\n \u003c/thead\u003e\n \u003ctbody\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e1\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9.420\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9.361\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e16.223\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.480\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e54\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8.727\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10.131\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e75\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13.761\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6.430\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17.204\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.150\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e16.161\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.480\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e2\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10.590\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8.465\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17.033\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.181\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e77\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9.337\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9.418\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e64\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e18.239\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4.860\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17.443\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.080\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17.618\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.030\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e70\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e3\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13.694\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6.441\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17.697\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.018\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e16.137\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.493\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e19.537\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4.540\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17.760\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4.990\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e21.928\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4.050\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17.480\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.0755\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e24.240\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.675\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e99\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17.133\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e5.176\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e23.966\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e24.205\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.674\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e31.520\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.836\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e5\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e18.953\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4.682\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25.193\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.534\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e79\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e20.860\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4.263\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e24.992\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.56\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25.310\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.516\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e32.184\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.779\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e50\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e19.393\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4.571\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e26.667\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.343\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e21.077\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4.212\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25.955\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.430\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e28.709\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.107\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e32.424\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.759\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e55\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e7\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e23.999\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.704\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e28.660\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.112\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e24.067\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.693\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e51\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e27.769\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.21\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e34.604\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.590\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e32.630\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.742\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e26.623\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.346\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e30.957\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.886\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e36\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25.150\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.534\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e41\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e29.454\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.030\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e6\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35.307\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.540\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e33.014\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.711\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e28.530\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.123\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e32.375\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.771\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e47\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e26.493\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.368\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e59\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e31.115\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.872\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e45\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35.553\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.523\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e33.915\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.641\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e29.440\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.030\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e53\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e34.597\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.595\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e28.443\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.127\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e69\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e32.472\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.755\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e4\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35.743\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.510\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35.524\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.525\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e30.957\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.886\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35.244\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.543\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e34\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e29.440\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e3.037\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e71\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e34.168\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.622\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e80\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35.846\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.503\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35.670\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.515\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e36.070\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.490\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35.680\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.512\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e38\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e30.913\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.891\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e31\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e37.009\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.427\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e38.506\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.336\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e39.527\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.278\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e70\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e39.450\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.281\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e38.453\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.341\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e32.343\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.766\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e37\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e39.636\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.272\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e39.151\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.299\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e13\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e39.763\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.265\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e45\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e43.307\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.093\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e39.147\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.301\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e55\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e39.407\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.287\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e39\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e42.173\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.141\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e39.365\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.287\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e41.029\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.198\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e44.520\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.033\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e12\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e39.840\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.265\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e62\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e39.753\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.266\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e51.222\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.782\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e39.763\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.265\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e42.401\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.130\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e16\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e47.597\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.190\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e40.533\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.227\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e42\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e43.133\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.095\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e57.322\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.606\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e40.528\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.224\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e70\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e44.300\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.043\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e48.723\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.872\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e46.557\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.948\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e44.867\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e20.020\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e33\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e59.219\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.559\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e41.623\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e2.168\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e49.960\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.824\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e35\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e57.433\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.604\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e9\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e49.980\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.824\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e40\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e47.467\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.917\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e43\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e61.164\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.514\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e10\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e46.584\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.948\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e50.166\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.817\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e25\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e19\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e60.727\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.525\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e8\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e57.780\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.595\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e48.507\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.675\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e44\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e62.963\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.475\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e14\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e49.960\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.824\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e17\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e53.310\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.717\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003ctr\u003e\n \u003ctd align=\"left\"\u003e\n \u003cp\u003e20\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e64.887\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.437\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e11\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e64.757\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.438\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e30\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e49.937\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.827\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e100\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e68.423\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.370\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e18\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e57.743\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.595\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e15\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e57.322\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e1.606\u003c/p\u003e\n \u003c/td\u003e\n \u003ctd align=\"char\"\u003e\n \u003cp\u003e55\u003c/p\u003e\n \u003c/td\u003e\n \u003c/tr\u003e\n \u003c/tbody\u003e\n \u003c/table\u003e\n \u003c/div\u003e\n \u003cp\u003e\u003cbr\u003e\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec8\"\u003e\n \u003ch2\u003eMicroscopic FTIR spectroscopy analysis\u003c/h2\u003e\n \u003cp\u003eMicroscopic FTIR spectroscopy is used to study the dark blue pigment samples of the donor\u0026rsquo;s streamers on the south wall of the tunnel. Under the microscope, it can be seen that there are blue and green pigment particles distributed. These two kinds of particles are analyzed separately, and the results are shown in Figure 5a. The blue pigment particles have absorption peaks at 3427cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, 1463cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, 1408cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, 1090cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, 948cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, 837cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e and 767cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, which are very close to the peak positions of azurite in the literature. The green pigment particles have absorption peaks at 3441cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, 3346cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, 983cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, 951cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, 927cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, and 837cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, which are close to the peak position of atacamite[\u003cspan class=\"CitationRef\"\u003e13\u003c/span\u003e] and is consistent with the XRD results. Figure 5b shows the infrared spectrum of blue pigments used in statue repainted in the Qing Dynasty. There are absorption peaks at 3309cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, 1652cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, 1534cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, 1053cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, 795cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, and 593cm\u003csup\u003e\u0026minus;1\u003c/sup\u003e, which are very similar to smalt [\u003cspan class=\"CitationRef\"\u003e14\u003c/span\u003e, \u003cspan class=\"CitationRef\"\u003e15\u003c/span\u003e].\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec9\"\u003e\n \u003ch2\u003eMicroscopic analysis\u003c/h2\u003e\n \u003cp\u003eThe blue pigment used in the Five Dynasties shows a very uniform bright blue under single polarized light, with different particle sizes, and is completely extinct under orthogonal polarized light, which is consistent with the XRD analysis result, and so it is lazurite mineral (Figure \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003ea and \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003eb). There are blue and green particles in the dark blue pigment used in the Song Dynasty. Under single polarized light, the blue pigment particles are of different sizes. Large particles are dark blue and small particles are light blue. Blue particles mostly extinct under orthogonal polarized light and should be azurite. Under single polarized light, the green pigment particles are in the form of massive rocks, which should be natural atacamite (Figure \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003ec and \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003ed). Blue pigment used in the Qing Dynasty looks like sharp-edged glass shards under single-polarized light, varying from light blue to dark blue. They are completely extinct under cross-polarized light, with a refractive index of 1.55, which are identified as smalt (Figure \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003ee and \u003cspan class=\"InternalRef\"\u003e6\u003c/span\u003ef).\u003c/p\u003e\n \u003cp\u003eIn order to make out whether azurite and atacamite in the dark blue pigment are used separately or mixed with each other, the M256-03 dark blue block sample is embedded with resin. A polishing machine is used to polish the surface of the sample until there are no obvious scratches, and then observe it under a microscope. The result shows that green atacamite and blue azurite particles mixed with each other and the azurite particles are obviously more than the atacamite particles. It can be determined that the dark blue pigment used in the Song Dynasty is the mixture of green pigment and blue pigment (Figure 7).\u003c/p\u003e\n\u003c/div\u003e\n\u003cdiv class=\"Section2\" id=\"Sec10\"\u003e\n \u003ch2\u003eQuantitative analysis of micro-area X-ray fluorescence spectrometer\u003c/h2\u003e\n \u003cp\u003eThe micro-area X-ray fluorescence spectrometer is used for quantitative analysis of smalt pigment used in the Qing Dynasty. The result shows that the percentage of oxides in smalt pigment is: SiO\u003csub\u003e2\u003c/sub\u003e: 72.13%, K\u003csub\u003e2\u003c/sub\u003eO: 15.90%, CaO: 5.03%, Fe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e: 2.83%, CoO: 1.26%, NiO: 0.23%, and PbO: 2.62.\u003c/p\u003e\n\u003c/div\u003e"},{"header":"Discussion","content":"\u003cp\u003eBased on the results of XRF, XRD, M-FTIR and PLM analysis, the blue pigments used in the murals and statues of Cave 256 at different periods are different. Natural lazurite minerals were used as blue pigment in the Five Dynasties. Azurite was used as blue pigment in murals of the Song Dynasty. People also used the mixture of azurite and atacamite as dark blue. Smalt was used as the blue pigment in the Qing Dynasty.\u003c/p\u003e \u003cp\u003eIn the 3rd century AD, the lazurite pigment was introduced into the Western Regions from Afghanistan through the Silk Road, and then to the Central Plains through the Hexi Corridor[\u003cspan citationid=\"CR16\" class=\"CitationRef\"\u003e16\u003c/span\u003e]. Mr. Su believes that lazurite was used as a pigment from the Jin Dynasties (265-420 AD). Since then, lazurite pigments have been found in major grottoes in the northern region[\u003cspan additionalcitationids=\"CR18\" citationid=\"CR17\" class=\"CitationRef\"\u003e17\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR19\" class=\"CitationRef\"\u003e19\u003c/span\u003e]. A large number of lazurite were also used in the early Dunhuang murals. However, it gradually decreased after the 7th century, and the use of azurite gradually increased. Azurite has already occupied a dominant position in Dunhuang murals of the Tang Dynasty, which might be related to the discovery of azurite in the Qilian Mountains of Gansu in the Tang Dynasty[\u003cspan citationid=\"CR20\" class=\"CitationRef\"\u003e20\u003c/span\u003e]. Cave 256 of Mogao Grottoes was built in the Five Dynasties. Azurite was used as the blue pigment in most caves at that time. However, expensive lazurite was used in Cave 256. The repainting period of murals on the surface layer was about 60 years later than the excavation of Cave 256. Azurite used here instead of lazurite. There are two main reasons for this difference. Firstly, Cave 256 was the merit cave of Cao Yuanshen, the third military governor of Guiyi Army (a local armed regime that originated from the Tang Dynasty). During this period, the regime of Guiyi Army was stable and the economy developed rapidly. As the supreme ruler at the time, Cao Yuanshen had sufficient funding support to build caves and paint. The repainted cave belonged to Murong Yanchang, the military director of Yumen Town of the Guiyi Army, and his wife Yan in the Song Dynasty during the Cao Zongshou period. At this time, the Guiyi army regime began to go downhill. The Ganzhou Uighurs and Gaochang Uighurs continued to invade, and internal contradictions were numerous. As a result, they were short of money. They only afforded repainting an old cave because it cost too much to open a new one. Moreover, the cheaper azurite was used in a large area. Secondly, due to the unobstructed Silk Road, flourishing trade and the prosperity of the pigment market during the Cao Yuanshen period, lazurite was also relatively easy to obtain as an imported pigment. In the Cao Zongshou period (after the 11th century), frequent battles in the Hexi Corridor, traffic obstruction and social restlessness affected the source of pigments used in Dunhuang murals[\u003cspan citationid=\"CR21\" class=\"CitationRef\"\u003e21\u003c/span\u003e].\u003c/p\u003e \u003cp\u003eSmalt is a glassy pigment that develops color with cobalt element. It has been industrialized in Europe since the 15th century and it has been widely used in European oil paintings and church murals[\u003cspan additionalcitationids=\"CR23 CR24 CR25 CR26\" citationid=\"CR22\" class=\"CitationRef\"\u003e22\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR27\" class=\"CitationRef\"\u003e27\u003c/span\u003e]. In the 19th century, it was gradually replaced by other inexpensive artificial blue pigments. The usage of smalt pigment in China mostly occurred in the Qing Dynasty. The earliest evidence at present is the land-and-water drawing of Luochuan, Shaanxi painted in the thirtieth year of Kangxi (1691AD) [\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e]. This pigment is concentrated in Beijing and Shanxi and scattered in other areas [\u003cspan additionalcitationids=\"CR30\" citationid=\"CR29\" class=\"CitationRef\"\u003e29\u003c/span\u003e\u0026ndash;\u003cspan citationid=\"CR31\" class=\"CitationRef\"\u003e31\u003c/span\u003e]. The forms of cultural relics are mainly architectural murals, colored paintings and statues. The smalt pigment used in statue of the Qing Dynasty in Cave 256 is reported for the first time in the murals and statues of Mogao Grottoes.\u003c/p\u003e \u003cp\u003eOxide percentages of the smalt pigment used in colored paintings founded in Beijing, Shanxi, Inner Mongolia and Sichuan, blue and white porcelains of the Yuan Dynasty and the Ming Dynasty, Greek murals and European oil paintings are listed in Table \u003cspan refid=\"Tab3\" class=\"InternalRef\"\u003e3\u003c/span\u003e. It can be seen that the oxide content of smalt pigment used in China was close to that of European murals and oil paintings: they all contained about 70% SiO\u003csub\u003e2\u003c/sub\u003e, the content of K\u003csub\u003e2\u003c/sub\u003eO generally exceeded 10%, and the content of the color rendering element Co was 1%-5%. In addition, they also contained Fe, Ca, Ni, As, Pb and other elements. The smalt pigment found in Cave 256 is also one of this type of material. However, as for the smalt pigment used in blue and white porcelains of the Yuan Dynasty and the Ming Dynasty, the content of SiO\u003csub\u003e2\u003c/sub\u003e was close, K\u003csub\u003e2\u003c/sub\u003eO was relatively low, Al\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e was about 15% and the content of the color rendering element Co was generally lower than 0.5%. In summary, the smalt pigment used in statue of Cave 256 should be imported from Europe.\u003c/p\u003e \u003cp\u003eIn this study, the smalt pigment is firstly founded in statues of the Qing Dynasty in Mogao Grottoes in Dunhuang. According to previous literature, artificial ultramarine pigments were generally used for remodeling and repainting of statues of Mogao Grottoes during the Qing Dynasty. The smalt pigment discovered this time can be used as a reference for us to study the history of repainting and repairing of statues in Cave 256. The smalt pigment was a very important blue paint in the history of European art. It was regarded as the only artificial substitute for azurite and Lazurite until the invention of artificial ultramarine. There is evidence that the export of smalt pigment from Europe to China covered almost the entire 18th century and continued into the 19th century[\u003cspan citationid=\"CR34\" class=\"CitationRef\"\u003e34\u003c/span\u003e, \u003cspan citationid=\"CR35\" class=\"CitationRef\"\u003e35\u003c/span\u003e]. After the mid-19th century, artificial ultramarine entered China. With low price and strong hiding power, it quickly replaced smalt. Kangxi actively explored the Western Regions in his later years. Taking this as a chance, he began to manage the area west of Jiayuguan. During the 5th-6th year of Yongzheng, 2405 households, about 10,000 people, immigrated to Dunhuang. The arrival of immigrants laid the foundation for the development of Dunhuang in the Qing Dynasty and even in modern times[\u003cspan citationid=\"CR36\" class=\"CitationRef\"\u003e36\u003c/span\u003e]. According to \u003cem\u003eInscriptions for Donors of Mogao Grottoes in Dunhuang\u003c/em\u003e (Cave 454), the pedagogue Lei Jixiang completed his donation on February 15th of the lunar calendar in the first year of Yongzheng[\u003cspan citationid=\"CR37\" class=\"CitationRef\"\u003e37\u003c/span\u003e]. It can be concluded that the first year of Yongzheng (1723 AD) should be the earliest date for the reconstruction of the Mogao Grottoes in the Qing Dynasty. Based on the history of the introduction of smalt into China and the history of the reconstruction of Mogao Grottoes in the Qing Dynasty, it is believed that the statues of Cave 256 were rebuilt in the first half of the 19th century, that is, during the reign of Jiaqing and Daoguang in the Qing Dynasty.\u003c/p\u003e \u003cp\u003e \u003cdiv class=\"gridtable\"\u003e\u003ctable float=\"Yes\" id=\"Tab3\" border=\"1\"\u003e \u003ccaption language=\"En\"\u003e \u003cdiv class=\"CaptionNumber\"\u003eTable 3\u003c/div\u003e \u003cdiv class=\"CaptionContent\"\u003e \u003cp\u003eComparison of element content of smalt pigment in different regions[\u003cspan citationid=\"CR28\" class=\"CitationRef\"\u003e28\u003c/span\u003e][\u003cspan citationid=\"CR32\" class=\"CitationRef\"\u003e32\u003c/span\u003e, \u003cspan citationid=\"CR33\" class=\"CitationRef\"\u003e33\u003c/span\u003e]\u003c/p\u003e \u003c/div\u003e \u003c/caption\u003e \u003ccolgroup cols=\"15\"\u003e \u003cthead\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c1\" morerows=\"1\" rowspan=\"2\"\u003e \u003cp\u003eSource\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colspan=\"14\" nameend=\"c15\" namest=\"c2\"\u003e \u003cp\u003eOxide percentage (Wt%)\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003ctr\u003e \u003cth align=\"left\" colname=\"c2\"\u003e \u003cp\u003eNa\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c3\"\u003e \u003cp\u003eAl\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c4\"\u003e \u003cp\u003eSiO\u003csub\u003e2\u003c/sub\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c5\"\u003e \u003cp\u003eK\u003csub\u003e2\u003c/sub\u003eO\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c6\"\u003e \u003cp\u003eCaO\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c7\"\u003e \u003cp\u003eFe\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c8\"\u003e \u003cp\u003eMnO\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c9\"\u003e \u003cp\u003eC\u003csub\u003eO\u003c/sub\u003eO\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c10\"\u003e \u003cp\u003eNiO\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c11\"\u003e \u003cp\u003eCuO\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c12\"\u003e \u003cp\u003eMgO\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c13\"\u003e \u003cp\u003eBaO\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c14\"\u003e \u003cp\u003eAs\u003csub\u003e2\u003c/sub\u003eO\u003csub\u003e3\u003c/sub\u003e\u003c/p\u003e \u003c/th\u003e \u003cth align=\"left\" colname=\"c15\"\u003e \u003cp\u003ePbO\u003c/p\u003e \u003c/th\u003e \u003c/tr\u003e \u003c/thead\u003e \u003ctbody\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCave 256 of Mogao Grottoes\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e72.13\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e15.90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e5.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e2.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1.26\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e0.23\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c15\"\u003e \u003cp\u003e2.62\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCining Palace, Forbidden City, Beijing\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.27\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e72.90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.62\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e5.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c14\"\u003e \u003cp\u003e6.54\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eChengqing Palace, Xiannong Temple, Beijing\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.19\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e1.50\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e73.32\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8.64\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e0.84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e1.03\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c14\"\u003e \u003cp\u003e4.60\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eJingxin Temple, Taigu, Shanxi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e66.41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e11.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e2.99\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e3.15\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e0.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c14\"\u003e \u003cp\u003e12.46\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c15\"\u003e \u003cp\u003e1.22\u003c/p\u003e \u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eSanqing Palace, Shanxi\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.53\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e73.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e11.41\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e2.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e3.40\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.02\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c13\"\u003e \u003cp\u003e0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c14\"\u003e \u003cp\u003e8.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eQianfo Cliff, Guangyuan, Sichuan\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.33\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e80.67\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e8.44\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e0.04\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e3.59\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e3.90\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c11\"\u003e \u003cp\u003e0.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e0.08\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c14\"\u003e \u003cp\u003e2.30\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eDazhao Temple, Inner Mongolia\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e0.91\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e0.12\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e77.63\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e13.82\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e1.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e1.00\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c10\"\u003e \u003cp\u003e0.77\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c14\"\u003e \u003cp\u003e3.89\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCobalt of blue and white porcelain of the Yuan Dynasty\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e3.14\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e15.22\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e68.05\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e2.74\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e8.78\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e1.73\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.37\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e0.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCobalt of blue and white porcelain of the Yuan Dynasty\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2.68\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e14.79\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e66.76\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e4.39\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e6.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e2.83\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0.11\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.47\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c12\"\u003e \u003cp\u003e0.36\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eCobalt of blue and white porcelain of the early Ming Dynasty\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c2\"\u003e \u003cp\u003e2.84\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c3\"\u003e \u003cp\u003e15.35\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e68.94\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e3.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e5.98\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e2.17\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c8\"\u003e \u003cp\u003e0.25\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e0.24\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eGreece murals\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e68.93\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e22.59\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c6\"\u003e \u003cp\u003e2.16\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"char\" char=\".\" colname=\"c7\"\u003e \u003cp\u003e2.49\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e4.09\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003ctr\u003e \u003ctd align=\"left\" colname=\"c1\"\u003e \u003cp\u003eEuropean oil painting\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c2\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c3\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c4\"\u003e \u003cp\u003e66-72\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c5\"\u003e \u003cp\u003e10-21\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c6\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c7\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c8\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c9\"\u003e \u003cp\u003e2-18\u003c/p\u003e \u003c/td\u003e \u003ctd align=\"left\" colname=\"c10\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c11\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c12\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c13\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c14\"\u003e\u0026nbsp;\u003c/td\u003e \u003ctd align=\"left\" colname=\"c15\"\u003e\u0026nbsp;\u003c/td\u003e \u003c/tr\u003e \u003c/tbody\u003e \u003c/colgroup\u003e \u003c/table\u003e\u003c/div\u003e \u003c/p\u003e"},{"header":"Conclusion","content":"\u003cp\u003ePigment is an indispensable and the most important material in the process of making murals and statues. Pigments used in murals and statues in different historical periods of Mogao Grottoes are also different because of factors such as the origin of the pigments, processing techniques, prices, etc. In this paper, blue pigments used in murals and statues of the Five Dynasties, the Song Dynasty and the Qing Dynasty of Cave 256 are studies. The result shows that expensive lazurite pigment was used in the murals of the Five Dynasties and azurite was used on a large scale in the repainted murals of the Song Dynasties, which was closely related to the social status of the cave owner and the historical background at that time. The blue pigment in the repainted statues of the Qing Dynasty was smalt, which was first discovered in the Mogao Grottoes. It is judged that it is an imported pigment from Europe based on the element composition. Based on the history of the reconstruction of Mogao Grottoes in the Qing Dynasty, it is believed that the statues of Cave 256 were rebuilt in the first half of the 19th century, that is, during the reign of Jiaqing and Daoguang in the Qing Dynasty. In summary, the analysis and research of pigments in a specific historical period can reflect the social development at that time on the one hand, and on the other hand can provide scientific evidence for us to analyze the reconstruction and repainting history of the murals and statues of Mogao Grottoes.\u003c/p\u003e"},{"header":"Abbreviations","content":"\u003cdiv class=\"DefinitionList\"\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003epXRF\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eportable X-ray fluorescence\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003e\u0026micro;-FTIR\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003emicroscopic flourier transformed infrared spectroscopy\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eXRD\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eX-ray diffraction\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003ePLM\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003epolarizing microscope\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003cdiv class=\"DefinitionListEntry\"\u003e \u003cdiv class=\"Term\"\u003eED-XRF\u003c/div\u003e \u003cdiv class=\"Description\"\u003e \u003cp\u003eenergy dispersive X-ray fluorescence.\u003c/p\u003e \u003c/div\u003e \u003c/div\u003e \u003c/div\u003e"},{"header":"Declarations","content":"\u003cp\u003e\u003cstrong\u003eAvailability of data and materials\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eAll data generated or analyzed during this study are included in this published article.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eCompeting interests\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors declare that they have no competing interests.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eFunding\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThis research is supported by the Local Project Guided by the Central Government of Gansu Province, Science and Technology Project of Gansu Province (Grant No. 21JR7RA759) and Joint Fund for Regional Innovation and Development of National Natural Science Foundation of China(U21A20282).\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAuthors\u0026rsquo; contributions\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eBMS and MLS provided support and guidance for this study. BWS and ZRY performed XRD, PLM and performed the analysis. QC, ZYY performed XRF and prepared the manuscript. ZW performed M-FTIR and prepared the manuscript. All authors read and approved the final manuscript.\u003c/p\u003e\n\u003cp\u003e\u003cstrong\u003eAcknowledgements\u003c/strong\u003e\u003c/p\u003e\n\u003cp\u003eThe authors would like to acknowledge Dr. Li Na at the National Museum of China，for her guidance and expertise. Authors would like to thank the peer reviewers and editors for providing valuable feedback.\u003c/p\u003e"},{"header":"References","content":"\u003col\u003e\n \u003cli\u003eChen GQ. Study on Salting Damage Analysis and Treatment of Wall Paintings at Mogao Grottoes, Dunhuang. Lanzhou: Lanzhou University, 2016: 1-4 (in Chinese).\u003c/li\u003e\n \u003cli\u003eDunhuang Academy. Summary of the Contents of the Dunhuang Grottoes. Beijing: Cultural Relics Press. 1996\u0026nbsp;(in Chinese).\u003c/li\u003e\n \u003cli\u003eHe SZ. 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Research on Pigments for Decorative Polychrome Painting in Official Handicraft Regulations and Precedents of Qing Dynasty. Beijing, Tsinghua University, 2019: 318 (in Chinese).\u003c/li\u003e\n \u003cli\u003eChen GW. Study on Dunhuang Population Issues in Qing Dynasty. Journal of Dunhuang Studies, 2018 (1): 55-67 (in Chinese).\u003c/li\u003e\n \u003cli\u003eDunhuang Academy. Inscriptions for Donors of Mogao Grottoes in Dunhuang. Beijing: Cultural Relics Press, 1986 (in Chinese).\u003c/li\u003e\n\u003c/ol\u003e"}],"fulltextSource":"","fullText":"","funders":[],"hasAdminPriorityOnWorkflow":false,"hasManuscriptDocX":true,"hasOptedInToPreprint":true,"hasPassedJournalQc":"","hasAnyPriority":false,"hideJournal":false,"highlight":"","institution":"","isAcceptedByJournal":true,"isAuthorSuppliedPdf":false,"isDeskRejected":"","isHiddenFromSearch":false,"isInQc":false,"isInWorkflow":true,"isPdf":false,"isPdfUpToDate":true,"isWithdrawnOrRetracted":false,"journal":{"display":true,"email":"[email protected]","identity":"npj-heritage-science","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"hsci","sideBox":"Learn more about [Heritage Science](http://heritagesciencejournal.springeropen.com)","snPcode":"40494","submissionUrl":"https://submission.nature.com/new-submission/40494/3","title":"npj Heritage Science","twitterHandle":"@SpringerOpen","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true},"keywords":"Mogao Grottoes, mural, statues, Cave 256, Lazurite, Azurite, Smalt","lastPublishedDoi":"10.21203/rs.3.rs-1266982/v1","lastPublishedDoiUrl":"https://doi.org/10.21203/rs.3.rs-1266982/v1","license":{"name":"CC BY 4.0","url":"https://creativecommons.org/licenses/by/4.0/"},"manuscriptAbstract":"\u003cp\u003eMurals of Cave 256, Mogao Grottoes consist of several layers, with the outermost layer overlays all others. The bottom layer was painted in the Five Dynasties. The outermost layer was mural of the Song Dynasty. Statues were repainted in the Qing Dynasty. We found that different blue pigments are used through research of murals and statues of different dynasties in Cave 256. In order to know the type of blue pigments, technology such as X-ray diffraction, microscopic FTIR spectroscopy and polarizing microscope were used for analysis of trace samples based on non-destructive research through the portable X-ray fluorescence. As a result, we know that Lazurite was used as blue pigment in murals of the Five Dynasties and Azurite was used in the Song Dynasty. Smalt used in statues of the Qing Dynasty was first discovered in Mogao Grottoes. Difference in blue pigments reflects the social development at that time to a certain extent. It can be inferred from the discovery of smalt that statues of the Qing Dynasty in Cave 256 were repainted in the first half of the 19th century.\u003c/p\u003e","manuscriptTitle":"Study on blue pigments in Cave 256, Mogao Grottoes: Five dynasties, Song Dynasty and Qing Dynasty","msid":"","msnumber":"","nonDraftVersions":[{"code":1,"date":"2022-01-31 19:57:00","doi":"10.21203/rs.3.rs-1266982/v1","editorialEvents":[{"type":"communityComments","content":0},{"type":"editorInvitedReview","content":"","date":"2022-01-29T10:52:46+00:00","index":0,"fulltext":""},{"type":"reviewersInvited","content":"","date":"2022-01-29T02:55:55+00:00","index":"","fulltext":""},{"type":"editorAssigned","content":"","date":"2022-01-27T09:42:57+00:00","index":"","fulltext":""},{"type":"submitted","content":"Heritage Science","date":"2022-01-26T20:13:39+00:00","index":"","fulltext":""}],"status":"published","journal":{"display":true,"email":"[email protected]","identity":"npj-heritage-science","isNatureJournal":false,"hasQc":true,"allowDirectSubmit":false,"externalIdentity":"hsci","sideBox":"Learn more about [Heritage Science](http://heritagesciencejournal.springeropen.com)","snPcode":"40494","submissionUrl":"https://submission.nature.com/new-submission/40494/3","title":"npj Heritage Science","twitterHandle":"@SpringerOpen","acdcEnabled":true,"dfaEnabled":true,"editorialSystem":"em","reportingPortfolio":"BMC/SO AJ","inReviewEnabled":true,"inReviewRevisionsEnabled":true}}],"origin":"","ownerIdentity":"60450804-9db3-4328-b615-0057e457051a","owner":[],"postedDate":"January 31st, 2022","published":true,"recentEditorialEvents":[],"rejectedJournal":[],"revision":"","amendment":"","status":"under-review","subjectAreas":[],"tags":[],"updatedAt":"2022-05-30T21:25:57+00:00","versionOfRecord":[],"versionCreatedAt":"2022-01-31 19:57:00","video":"","vorDoi":"","vorDoiUrl":"","workflowStages":[]},"version":"v1","identity":"rs-1266982","journalConfig":"researchsquare"},"__N_SSP":true},"page":"/article/[identity]/[[...version]]","query":{"redirect":"/article/rs-1266982","identity":"rs-1266982","version":["v1"]},"buildId":"_2-kVJe1T_tPrBINL-cwx","isFallback":false,"isExperimentalCompile":false,"dynamicIds":[84888],"gssp":true,"scriptLoader":[]}