Abstract:Laser cleaning can cause color changes and other modifications of the physical-chemical properties of bronze surfaces. The paper studied the agar gel-mediated laser cleaning with the aim of optimizing the cleaning effects. First, we conducted research on how the gel influences laser energy and its ablation mechanism by measuring the energy attenuation of laser passing through gel sheets and carrying out ablation tests on bronze samples as well as on heat-sensitive paper. Then, cleaning experiments were done on bronze samples to compare the cleaning effectiveness of the gel-mediated method with that of wet laser cleaning and mechanical cleaning. Video microscopy, scanning electron microscopy, energy-dispersive X-ray spectrometry and X-ray diffraction were used for evaluation. The results demonstrate that the gel could bring moderate attenuation to laser energy and thus reduce the micro-structural modifications, making cleaning operations more versatile. With efficacy and safety requirements balanced, it is concluded that the gel-mediated method optimizes cleaning effects and has potential in the future applications.

Abstract:Gelatin with alum was widely used in the mounting and conservation of Chinese calligraphy and paintings, but it is also one of the important materials resulting in paper acidification. To investigate the applicability of modified collagen to pigment fixing for Chinese calligraphy and paintings, we studied the effect of a fixing solution made from fish glue, chitosan and konjac glucomannan on the properties of Xuan paper and three pigments. The results showed that after the treatment with the fixing solution:1) a gel coating was formed on the paper fiber surface, obviously improving the mechanical properties of Xuan paper and 2) aging of pigments was slowed to some extent compared with those treated with gelatin and alum.

Abstract:Using the nondestructive near infrared (NIR) testing technology, we built NIR prediction models including four indicators of pH value, degree of polymerization (DP), K-value and alkaline reserve of paper, based on the measured values of 100 paper samples. The correlations of NIR prediction models were verified. The results show that the predicted values of pH, DP and K-value have good agreement with the measured ones, suggesting that the three indicators can be tested by NIR. However, the correlation between the predicted and the measured values of alkaline reserve is not that good, suggesting that the NIR prediction models of alkaline reserve can be used for reference, but not testing. This study indicates that the nondestructive test of precious ancient papers by NIR technology is feasible.

Abstract:Evaluation of the failure of typical polymeric materials used to conserve polychrome potteries has long been a focus of conservators. In contrast to the pure polymers themselves, the rules for failure of these polymers when used for repair of polychrome potteries are more complicated. In this study, we explored the effective lifetimes of three typical conservation materials, namely pure acrylic emulsion, silicone acrylic emulsion and paraloid-B72. The macroscopic properties of the samples were measured to determine the strength of these materials. Reversible rates of the conservation materials were analyzed by photodecomposition curves and linear regression method to calculate the ages of the three materials in UV irradiation environments. Thermogravimetric analysis methods were used to predict thermal aging lifetimes. The results show that the conservation materials are more durable in stable environments than in those with variation in UV light, water or temperature. The study provides theoretical guidance for storage of fragile polychrome potteries which have been conserved using polymeric materials. Although the experiments and calculations in this paper have some limitations, this exploratory work offers a way to predict the lifetimes of cultural relic conservation materials.

Abstract:Crack filling can effectively prevent further development of cracks and leakage of rainwater, enabling kiln sites to be better preserved. In order to select suitable grouting materials for crack filling in kilns with moisture problems, we conducted a study on modification of soils from four sites on the Maritime Silk Road in Zhejiang and Fujian provinces. We used calcined ginger nuts, calcined Aga soil and oyster ash. We tested compressive strengths, flexural strengths and shrinkage rates of the modified grouting materials at different ages, as well as their changes of mechanical properties before and after temperature and humidity cycle tests, freezing and thawing cycle tests, water stability tests, stability tests and alkali resistance tests. The result shows that all three of the types of lime materials demonstrate good weathering resistance, but the oyster ash-modified samples are characterized by having relatively weaker resistance to freezing and thawing, lower aging strengths and larger shrinkage deformations. In contrast, the samples modified with calcined ginger nuts demonstrate their higher aging strength, smaller shrinkage deformation, as well as resistance to weathering. Therefore, it is suggested that calcined ginger nuts be used in grouting materials for crack filling in these four kiln sites. The related research results have a practical significance in terms of the selection of grouting materials for crack filling.

Abstract:The air temperature, humidity and pressure in Cave 108 of the Mogao Grottoes were monitored by twelve sensors set at different positions inside. The results show that the air temperature in the cave has obvious daily and long-term variations. The variation amplitude of the upper part of the cave is larger than that of the lower part. In summer, the temperature of the upper part is also higher than that of the lower part. The absolute humidity of the air inside is seriously affected by the environment outside the cave and has a daily variation as well. Regarding the distribution, the air humidity is higher in the upper and the front parts of the cave than in the lower and the rear parts. There exists a net water vapor input from outside, but not through the cave entrance. Similarly, affected by the environment outside, the air pressure also has a clear daily variation and is higher on the east side of the cave than on the west side. All of these results above indicate that the moisture and heat sources of Cave 108 exist near the upper part of the east side of the cave.

Abstract:We have done a comparative analysis of samples selected from 17 Han dynasty bronze mirrors from Shangmashan in Anji, Zhejiang Province and Linzi, Shandong Province, using a combination of stereo, metallographic and scanning electron (with energy dispersive spectrometry) microscopy. The results show that 1) the surfaces of the bronze mirrors from Shangmashan are better preserved (similar to “Heiqigu”, ancient bronzes with dark protective layers like black lacquer), with preferential corrosion of the α-phase in the inner layer; 2) the bronze mirrors from Linzi have heavy surface corrosion, with deposition of cuprous oxide and basic cupric minerals outside and preferential corrosion of the δ-phase inside. Pourbaix diagrams were used in the analysis and discussion of the environments of these two corrosion phenomena. It appears that the preferential types of corrosion seen in the α-phase and the δ-phase in the inner layer of high tin bronze mirrors seen in different environments are related to the different corrosion products outside.

Abstract:Previous research indicates that portable X-ray fluorescence (pXRF) can be used for quantitative compositional analysis of bronzes non-destructively and in-situ. In order to investigate the bronze culture in the Xiangyun area of western Yunnan, we used pXRF to analyze 357 bronzes unearthed from cemeteries at Dabona, Jianchun and Hongtupo. The results show that the types of alloy are mainly copper and tin bronze, but there are also small amounts of Pb-Sn bronze and Cu-As alloy. The alloy ratio patterns of Sn to Pb of the three cemeteries are highly consistent and indicate that the bronze techniques used during different periods in the Xiangyun area all belong to “Kunming Yi” tradition. Some bronzes also contain iron in their matrix compositions. Dabona bronzes are almost free of iron while the other cemeteries have many high iron bronzes. The ancestors of Dabona area may have adopted different smelting techniques. All of the Cu-As alloy bronzes came from Hongtupo cemetery. It can be speculated that the Cu-As alloy, and even the technique of making it was introduced to the Xiangyun area from the northwest area along the semilunar culture communication belt.

Abstract:Edge gilding is a traditional manual decoration technology used in hardcover book binding in Europe. Gold leaf was applied to the book edge to give it a golden-mirror look. In recent years, domestic restorers are encountering more and more western ancient books that need to be repaired. It is necessary to study this technology and to review related traditional conservation methods. In this paper, we discuss in detail the brief history, main process, tools and materials used and the technical parameters of edge gilding, with the aim of providing a reference for the repair of ancient western books.

Abstract:To investigate the structural component importance of traditional Chinese timber structures, we took post-and-lintel and column-and-tie timber structures, two typical residential timber structures in Jiangsu and Zhejiang areas, as the research targets. Based on energy method, the change of unit volume towards the strain energy of the whole structure after component attribute alteration was employed as the component importance evaluation index. By the finite element software Ansys (16.0), an implementing procedure was developed to assess the component importance of traditional timber structures using the element birth-death method and altering elastic modulus method, respectively. The analysis results show that the altering elastic modulus method is more suitable for calculation and analysis of component importance of traditional timber structures. Through the component importance analysis of one single and the whole frame under the vertical loads and the horizontal seismic action, the component importance coefficient and the sorting results of post-and-lintel and column-and-tie timber structures were obtained and the key components of traditional timber structures were thus selected accordingly. In addition, the analysis results can provide a scientific and reasonable theoretical basis for the determination of critical components of traditional timber heritages in the process of maintenance and structural health monitoring.

Abstract:X-ray photography is a traditional non-destructive testing technology, generally used to study relics made of various materials. Recently, with the rise of digital imaging technology, the process of X-ray photography has been greatly simplified, and digital images obtained can be observed, used and saved more easily. More importantly, the image editing process has become possible as well. Therefore, there are greater opportunities to develop X-ray. In this paper, using a wood carving as an example, we introduce the process of digital radiography. In addition, we also analyze and discuss the final three view images of X-ray photography after their being edited.

Abstract:It is becoming more and more popular in the cultural heritage field to disseminate cultural relic information using digital media. One of the important aims of digitizing cultural heritage data is to better use the archived digital data to enable the data to fulfill their roles. Using image technology based on analysis, we have proposed a new automated virtual restoration protocol for the Ming Dynasty murals of a Guanyin Temple in Xinjin. We found that the Criminisi algorithm, which is based on the exemplar image restoring model and which uses wavelet energy factors to guide the filling order, can restore information about missing parts very well. It adjusts the restoration rules using appropriate factors for images with different textures. The filling texture patches are from the remaining parts of the same mural, just as with real restoration methods.

Abstract:Paomadi Cemetery is located in Zhengji Town of Yicheng, Hubei province. A great number of bronze wares from the late Warring States Period to the Han Dynasty have been unearthed from the cemetery. This paper analyzed elemental compositions and metallographic structures of some bronze wares of this cemetery. We found that the bonzes of the later Warring States Period can be categorized as lead-tin bronzes or tin bronzes, depending on the function of the bronzes. The bronzes of the Han Dynasty are mostly lead-tin bronzes with lower alloy composition and wider alloy compositional ranges in comparison to those of the Late Warring States Period. Most of the bronzes analyzed were cast metal; however, three pieces were hammered. The three hammered bronzes are all utensils with open-tops and thin walls.

Abstract:Huashan rock artworks in Ningming County are ancient paintings drawn on cliffs by the Luo Yue people (ancestors of the Zhuang people) from the 5th century B.C. to the 2nd century AD. As remnants reflecting the religious activities of these ancient people, the rock artworks have significant historical and cultural values, as well as artistic charms. However, during the past two millennia or more, a series of relic diseases such as cracking, peeling and fading, etc., due to the effects of geological and environmental factors, have resulted in unclear and incomplete images, which seriously affect the integrity of the pictures and create difficulties for research work. Similar to “Quan Se” and “Jie Bi”(two methods of painting and calligraphy restoration), we adopted a panoramic overview of these disease-damaged rock artworks, looking at them from an artistic perspective in order to restore their original images as much as possible. The results not only have great significance in terms of further investigations into intent of the Luo Yue people in painting them, understandings of the pictorial information and studies of combination ways of the rock images, but also provide basic analysis and evaluation data for rock art restoration in the future, and technical references for identification of similar rock art images.

Abstract:The aging of paper relics has always been an important research problem in conservation. Previously, the aging of paper was assessed by visual observation, and was often based much on the overseers’ experience. The physical strength and degree of polymerization could not be tested because of the shortage of large numbers of suitable paper samples. In recent years, with the development of new analytical tools, including micro-confocal microscopy, near infrared Fourier transform and surface enhanced Raman spectroscopy, Raman-based spectroscopic methods have been more and more often used for the in-situ, non-destructive microanalysis of old paper relics. Some recent applications of Raman spectroscopy to the analysis of paper degradation and of carbon-based black and other pigments, as well as their relevant research status, are reviewed in this paper. With more research, Raman could also be used with other analytical techniques and quantitative methods. Raman spectroscopy will continue to play an important role in the study of paper relics.