Abstract:The hand scroll is the earliest traditional Chinese mounting form. Developed from the Jin to the Qing Dynasties, it is seen as having three classic styles:butted-edge, wrapped-edge and folded-edge hand scrolls. For the last style, there are two kinds of jointing techniques:jointing of whole silk and assembling of small pieces of silk. For most of the hand scrolls from the Qing Dynasty to the Republic of China that have been handed down to us, the technique of assembling of small pieces of silk, which saves more silk materials, was adopted. However, this process is complicated and difficult, resulting in its fading away and even the danger of being lost in the contemporary era. Using the restoration and re-mounting of a Ming Dynasty hand scroll in the Shanghai Museum collection as an example, this paper describes research on its original mounting materials, color matching and jointing technique, as well as the process of mounting for this folded-edge hand scroll according to its original size. This work studies, conserves and passes on the excellent traditional skills of our ancestors.

Abstract:During the preservation process of ancient calligraphy and paintings, mildew spots are easy to breed mildew stains not only affect the appearances of works, but also cause irreversible and permanent damage to paper cultural relics. In order to provide an intuitive reference for the cleaning of mildew stains on calligraphy and paintings, we proposed a method of stained area extraction and virtual restoration based on hyperspectral imaging. The 244 bands between 450~600 nm significantly different from the stained area spectral curve were selected as the characteristic bands, which were used to extract the stained area by the sequential maximum angle convex cone and gray-scale segmentation algorithm. Next, the hyperspectral image was transformed by the principal component analysis. The first three principal components were selected to synthesize a pseudo color image, which was restored virtually by typical algorithm of Criminisi. Then, inverse principal component transformation was performed on the restored image to complete the virtual restoration of the hyperspectral image. Taking a painting by Ni Tian as an example, we found that the restored stained area was better integrated with the painting body, the boundary was naturally smooth, and the root mean square error value generally became smaller. The research results could provide an intuitive restoration basis for the cleaning of mildew stains on calligraphy and paintings, and have strong practicability.

Abstract:Due to the influence of preservation environment and man-made destruction, most ancient Chinese prints have different degrees of defects, and their artistic and research value have been seriously damaged. Therefore, with the aim of reproducing the artistic style of ancient printmaking, virtual restoration of a Buddhist print with seriously incomplete images, from Huachi County Museum of Gansu Province, was carried out using a series of technologies such as image acquisition, digital painting and art micro spray, based on the color management system. This work has shown that the digital Quanse (which is taken to make the works as completely perfect as what it used to be by coloring) and Jiebi (which is a special way to make the works complete by mending the defects) technology can accurately restore graphics and colors without interfering with the original cultural relic, and that the replica after virtual restoration could be used as an image supplement. When displayed together with the traditionally restored cultural relic, it can improve the artistic aesthetics. These research results may provide a reference for the development of calligraphy and painting conservation and restoration technologies.

Abstract:Fiber identification is a necessary basic task for the conservation of paper-made relics, ancient books and documents, and is of great importance in making conservation plans and selecting repair materials. Calcium oxalate crystals are common ergastic substances in plants, and their forms are much related to the categories of plants. In this study, calcium oxalate crystals in the fibers of traditional handmade paper were observed using attenuated total reflection-Fourier transform infrared (ATR-FTIR) spectrometry, X-ray diffraction (XRD), scanning electron microscopy (SEM),optical microscopy (OM) and polarized light microscopy (PLM), to characterize calcium oxalate crystals in each kind of paper. Furthermore, the possibilities of adding the polymorphism of calcium oxalate crystals to the fiber identification system are also discussed as a means of improving the methodology of fiber identification.

Abstract:To achieve better conservation, utilization and display of a Han Dynasty brocade bag excavated from Shengjindian Cemetery in Turpan, Xinjiang Uygur Autonomous Region, study and restoration of it was carried out. Through non-destructive testing and disease assessments of its sheepskin and brocade, sufficient information was obtained to formulate a restoration plan. The results show that 1) the brocade is made of silk and the organization structure is plain weave with overlapping warp; 2) the particulate contaminant attached to the sheepskin strips is silicate; 3) diseases include contamination, wrinkles, missing portions and cracks. A restoration plan was formulated so as to retain the original information of the cultural relic, and then back-lining and various needlework methods were used to achieve a more ideal restoration effect.

Abstract:In order to study the development of ancient harnesses in China and their techniques of manufacture, multi-layer organic residues attached to the back of the bronze buckle in a harness (dated as coming from the Southern and Northern Dynasties to the early Tang Dynasty) unearthed from Shangmiao site in Xunyi County were detected using infrared spectrometry and scanning electron microscopy. The results show that 1) the black residue is animal leather which has been seriously aged, making it impossible to judge the species of animal and the tanning process; 2) the residual textile in the lower layer is made of hemp fiber in a plain weave, with a significant difference between warp and weft lines and a low weaving density. Both form the harness ties jointly. The study found for the first time that the manufacturing process of textile wrapping leather was used for the connectors of various bronze parts on the harness, demonstrating that, at that time, the development of the harness had become preliminarily mature and people fully recognized the characteristics and advantages of hemp products and animal leather as harness connectors and could combine the two.

Abstract:There is a snake-patterned bronze Fu from the Warring States Period in the Forbidden City. It was mainly used as a utensil for serving millet, rice and beans during sacrifices and banquets. With the help of X-radiography, X-ray fluorescence spectrometry, X-ray diffraction and laser Raman spectrometry, ultraviolet fluorescence photography and micro-infrared spectrometry, we carried out scientific testing on the internal injury conditions, rust phases and rust levels of the flat line, the original repair traces and the suspected “jelly” fractures, etc. The results show that the snake-patterned Fu had been severely damaged. The matrix composition was a copper-tin-lead alloy, and the main corrosion phases were black copper ore, cuprite and malachite. The organic substance used in the original restoration material was shellac, and antique finishes such as barium sulfate, zinc sulfide, calcium carbonate, lead-chrome yellow, ultramarine blue, Paris green and atacamite were used. Finally, based on the study of the snake pattern, the characteristics of the “Beijing-style” bronze restoration technique are explained. The original restoration technique for the snake-patterned Fu is not much different from the traditional bronze restoration technique of the Palace Museum, which should belong to the category of “Beijing-style” bronze restoration technique.

Abstract:Based on the field investigation of painted sculptures in Yunlin Temple of Yanggao County, the chemical compositions of pigments were analyzed using XRD, XRF, SEM-EDS, Raman spectrometry and other methods. It was found that painted sculptures in Yunlin Temple were made following a traditional process, but also had something special, such as paper mounting, use of mixed pigments and gold scratching, etc. Red pigments were red lead, cinnabar and iron red; green, Paris green and basic copper chloride; blue, azurite and ultramarine; and the black one, carbon black. This research comprehensively reveals the manufacturing techniques and materials for painted sculptures in the Great Buddha’s Hall of Yunlin Temple, enriches the understanding of the manufacturing techniques and materials for ancient painted sculptures, and lays a foundation for the implementation of conservation and restoration.

Abstract:The lamellar exfoliation of the glaze layer and efflorescence of the matrix of green glazed tiles from a representative parapet sited in the Museum of the Former German Governor’s House in Qingdao, were studied using scanning electron microscopy-energy dispersive spectrometry, micro-zone X-ray diffraction, thermal diffusion coefficient analysis, thermal expansion property analysis and interface tension analysis. The results show, first, that there were differences in thermal diffusivity, thermal expansion capacity and other interfacial properties of the protective material, glaze and matrix, which caused corrosion products containing phosphorus, lead and calcium to form at the interface between the matrix and glaze, especially at the ice crack extension area of the glaze layer; thus, decreasing the interfacial bonding strength between the matrix and glaze; the ice cracks were extended and connected to the cracks formed at the weak joints between the matrix and glaze, resulting in lamellar exfoliation of the glaze. Second, a calcium sulfate crystal zone was formed between the matrix with a protective layer and the internal interface, resulting in the increase of pores at the interface and a decrease of particle bonding strength, which was speculated to be the main factor causing the lamellar exfoliation of the unglazed matrix. This research on the internal causes of lamellar exfoliation of the glaze layer and matrix could provide a scientific basis for further conservation.

Abstract:The high-temperature firing technology is one of the three major breakthroughs in the history of China’s ceramic development. Therefore, firing temperature measurement for ancient ceramics has long been one of the core features in the field of scientific research on ancient ceramics. However, the existing method systems generally have problems, such as large measurement errors and unclear mechanisms. In view of this, based on the thermal expansion method for temperature measurement, a series of standard samples was prepared by fully considering the differences in composition, structure and properties of ancient porcelain bodies fired in north and south China. The relationship between the “turning point” of the thermal expansion curve of porcelain body and the chemical composition and firing temperature of the body was revealed, and the influencing factors and mechanism of the curve were deeply analyzed. On this basis, the Al₂O₃ content and sintering state itself were determined to be the key technological parameters that affect the temperature measurement using the thermal expansion method.

Abstract:It is commonly found that the white material CaSO₄2H₂O appears on the surfaces of archaeological sites in Shaanxi Province within a short time after excavation. In our research, soil columns were used to simulate the process of CaSO₄2H₂O surface deposition. The results show that the site formed a new interface layer after excavation, and groundwater migrated upward as a result of evaporation at the surface, simultaneously bringing soluble salts in the soil to the surface, gradually increasing concentration until reaching the peak values. The contents of Ca²⁺ and SO2-₄ ions in the surface soil were dozens of times higher than those in the original soil after the experiment, which indicated that the CaSO₄2H₂O on the surface of the site was the result of water and salt transport. This research could provide evidence for the prevention of CaSO₄2H₂O generation after site excavation.

Abstract:After the excavation of underground masonry heritage sites, fluctuations in environmental conditions, such as temperature and water content, are associated with many diseases, including shrinkage and cracking, salting out and microbial growth, etc. These increase the risk of accelerated deterioration of underground masonry heritage sites and are not conducive to the effective conservation of cultural relic value. We took the Shangfang Eastern Wu Tomb in Nanjing as the research object in order to clarify the correlation between the dependent environment and disease characteristics of semi-underground masonry building sites. We carried out an on-site survey, mapping and disease investigation, and also conducted indoor and outdoor environmental monitoring of the tomb for one year using monitoring facilities such as a weather station and temperature and humidity recorders. Parameters (temperature and relative humidity) outside, inside the protective shelter and within each of the burial chambers were compared, and correlations between different diseases and their dependent environments were made. These clearly defined the corresponding risks of deterioration in different areas of the burial chamber and could provide a reliable basis for the preventive conservation of semi-underground masonry building sites such as the Shangfang Eastern Wu Tomb and other sites as well.

Abstract:The infrared camera technology was used to monitor animal activities at four heritage sites representing cave temples and ancient buildings, from January 2018 to June 2021. A total of 10 946 independent wildlife photographs (6 orders, 13 families and 18 species) were collected within 9 463 camera-days by 22 cameras. According to the relative abundance index (RAI), the typical dominant species in Mogao Grottoes, Bingling Cave Temple, Maiji Mountain Grottoes and Zijin Nunnery were determined respectively to be:Rhombomys opimus (RAI:35.75), Columba rupestris (RAI:75.99), Sciurotamias davidianus (RAI:43.17) and Dremomys pernyi (RAI:43.65). The highest seasonal activities of the four dominant species are in summer and the lowest in winter. The highest monthly activity rhythm is in August and the lowest in January. The daily activity peaks of Rhombomys opimus, Columba rupestris, Sciurotamias davidianus and Dremomys pernyi are 8∶00~10∶00,10∶00~12∶00, 10∶00~12∶00 and 2∶00~4∶00, respectively. Mammals and birds mainly endanger cultural relics in the forms of scratches, nesting and fecal pollution, etc. Based on the above studies, targeted prevention and control measures are proposed. The results of this study could provide technological support and a scientific basis for clarifying the characteristics of animal populations, activity rhythms and animal control at heritage sites.

Abstract:Lacquerware, as one of the important symbols of the Chinese national culture, has long been a focus of conservation researchers. We took a Southern Song lacquerware fragment, unearthed in Wenzhou, Zhejiang Province, and decorated with carved patterns filled with paints, as the research object, and studied it using digital microscopy, upright fluorescence microscopy, SEM-EDS, micro-Raman spectrometry, FT-IR and Py-GC/MS. This work shows the micro-destructive analysis process of the complex matrix material/composition, structure and lacquering techniques for multilayer lacquerware. We summarize methods to detect commonly used materials in lacquerware. This article provides technological support for the research on lacquerware.

Abstract:In the Palace Museum, there is only one set of gilded and stone-inlaid bronze five-sacrificial utensils, which is beautiful in shape and exquisite in workmanship. However, one pair of flower goblets was seriously injured, resulting in a large number of missing inlays. Before restoration, the structure, inlay materials and adhesive material of the goblets were analyzed using CT, Raman, XRF and IR. The results show that 1) the adhesive material is “wax glue”, the formula of which has been lost; 2) the green inlays are turquoise, and the indigo-blue inlays are potash-lime glass with cobalt as the colorant and lead as the flux. During restoration, modern substitutes for the traditional “wax glue”, turquoise and lead-free cobalt blue glass were selected as repair materials based on the testing results. Also, more than 700 pieces of inlays have been restored and patched in an accurate, fast and orderly way following the principle of “fine zoning” and “focusing first and then carving slowly”. This work could provide a typical case for the restoration of large mosaic cultural relics.

Abstract:In the middle of the Neolithic Age, Chinese ancestors applied pottery-making techniques to the technology of construction and invented a series of building materials, made of burnt clay, that had significantly better strength and water resistance, which greatly improved the living conditions of ancient humans. In the middle and lower reaches of the Yangtze River, the process of evolution of Neolithic building construction is much more obvious, with burnt clay-made materials widely used. In our study, XRD, XRF, magnetic susceptibility measurements and colorimetry were used to comprehensively analyze the burnt clay samples of different cultural stages unearthed at Qixingdun site in Huarong, Hunan Province. The results show that the six burnt clay samples were probably building materials made from local soil, mixed with plant remains such as rice husk and rice straw and then baked. The equivalent firing temperature range of these burnt clay samples is 550~700 ℃.

Abstract:The Nanjing City Wall is the largest existing city wall in the world and it is important to evaluate its safety scientifically. The portion of the wall leaning against mountain is one of the main forms of the Nanjing City Wall, the loading characteristics of which are different from those of the self-bearing city wall because it is connected with soil. Our study summarizes six typical diseases of the portion of the wall leaning against mountain, and proposes a numerical modeling method for it to simplify it as a city wall-bonding interface-soil model. Using ABAQUS software, and in combination with corresponding engineering examples, a pre-warning analysis of overall collapse was carried out on the bulging deformation of the wall. The results show that with the decrease of soil strength, the displacement of the wall increases continuously, forming a bulge that will lead to collapse. [The pre-warning of deformation value can be established through the obvious inflection point on the city wall bottom tensile stress-top displacement curve.] Based on this value, the influence of the soil slope height on the overall collapse is discussed, and a reasonable value of slope angle is given. The soaking and swelling of the city wall bottom could reduce the strength of the bottom and result in a large relative displacement there. A warning can be alarmed when the bottom wall has the ultimate tensile strength based on observed maximum relative displacement. Finally, suggestions for the restoration and conservation of the wall are proposed.

Abstract:Inorganic or organic acid pollution gases in the ambient air of museums can corrode brick and stone cultural relics in the collection and cause harmful salts to be deposited on their surfaces. Common harmful salts have complex types and may contain both inorganic and organic acid anions. In order to further understand the salt damage to cultural relics and to analyze its causes, we developed a method for quantitatively analyzing inorganic and organic anions in harmful salts based on ion chromatography. This method can simultaneously determine 12 anions—fluoride, chloride, bromide, nitrate, nitrite, phosphate, sulfate, formate, acetate, propionate, butyrate and valerate—in harmful salts found on brick and stone cultural relics in the collection. With a gradient of 2~30 mmol/L KOH, the separation and accurate detection of the 12 anions could be achieved in 35 min. The correlation coefficients of their standard curves were higher than 0.995, the detection limits 0.001~0.022 μg/mL, the quantitation limits 0.004~0.073 μg/mL and the recovery rates 81.8%~107.0%. The solvent for this method was ultrapure water, and the sample was easy to handle. This method features low cost, short detection time and high accuracy. The mass fractions of inorganic and organic acid anions in harmful salts can be calculated quantitatively. This method was applied to the analysis of salt damage on the surfaces of a tile and an imitation censer in the collection of the National Museum of China, and suggests the types of environmental pollutants that led to the precipitation of harmful salts. This work provides a basis for preventing, delaying and predicting the occurrence of salt damage, as well as analyzing its causes.

Abstract:Cultural relics are materialized civilizations. The non-renewability of cultural relics determines that the research on them should take non-destructive ways which also stand at the research frontier of cultural relic conservation in recent years. With reference to the recent progress on the application of ultrasonic technology in China and abroad in this field, the review introduces several cases of evaluating weathering degrees, detecting internal flaws, underwater detection and restoration of cultural relics by means of the ultrasonic technology. Potential influencing factors are categorized and possible solutions are discussed. The ultrasonic technology is non-destructive, fast and accurate. More and more cases show that the ultrasonic technology will be more widely applied in the field of cultural relic conservation and provide new ideas for solving problems therein.