Abstract:Unearthed bronze relics are often damaged and have missing fragments. The traditional restoration method uses new hand-made parts to replace missing fragments and this approach often requires substantial efforts and time. Furthermore, these newly-attached fragments are difficult to detach and may also conceal and modify valuable information of how the original cultural relic is damaged. With the rapid progress of 3D printing’s accuracy and efficiency, as well as the application of new printing materials, 3D printing now offers multi-material composites besides just resin. Specifically, the development of metallic materials for 3D printing now allows the restoration of bronze relics to be conducted in a more scientific and effective way. In this paper, a case study of the restoration of a restructured late Shang Dynasty bronze Jia with beast-face vein from Shanghai Museum is used to explore the development of the traditional bronze relic repair skill using detachable fragments made by 3D printing, also known as detachable fitting. This new method has lesser interferences on the original properties of the cultural relics and also retains the restructuring traces, which have great research value themselves. We will see how the application of new 3D printing technologies for the restoration of bronze relics are conducted more safely and with greater precision, and achieves the delicate balance of minimal intervention to the cultural relic but yet possesses the optimal effect for exhibitions.

Abstract:D reconstruction is a digital technology used to acquire both three-dimensional geometric and texture information about cultural relics, and is of great significance for the conservation of cultural relics, establishment of digital archives, archaeological research, exhibition and mobile digital museum construction. This technique is of use for the study of immovable painted grotto sculptures. Such a sculpture is influenced by acquisition space and is rich in texture information. Existing 3D reconstruction methods cannot recover the exact color information on the surface of cultural relics while maintaining high reconstruction precision. Using the FOTOMOULD 3D reconstruction system, with dual-camera structured light, a 3D reconstruction of a painted Bodhisattva in Cave No.45 of Mogao Grottoes was carried out, yielding high-precision geometric information as well as information on color, texture and other details.

Abstract:A 3D point cloud dataset of the Terra-cotta Warriors was built by 3D laser scanning, and then a high-precision 3D solid mesh model was established with the assistance of Geomagic Studio and Hypermesh. Using the finite element method (FEM) simulation in the ankles of Terra-cotta Warriors, characteristics of Von Mises stress and deformation were investigated to determine the vulnerable parts of the ankle. The optimal proportion of the points simplified on each fragment was confirmed and applied to FEM simulation with the same condition as the original model, to verify the reliability of simplification. The results show that the whole structure can remain safe and stable under gravity, as the vulnerable part is in the left ankle. For most fragments, the optimal proportion is 60%~70%, which can effectively reduce the modeling time. The error of Von Mises stress in the points-simplified model is less than 15% compared with that of the original model. The stress contour and deformation pattern are also comparable with the original results, which means the process of points simplification can provide comparatively accurate results and save time.

Abstract:With the aim of conserving the Huai’an Watergate Site scientifically and reasonably, the geometrical size and structure of the site were obtained by surveying and mapping on site. Then obvious types of damage at the site were analyzed, including wall damage and wood pile damage, etc. After that, the finite element analysis method and the traditional calculation method were used to analyze the structural performance of the site, and the results of these methods were analyzed to find out hidden diseases. Finally, based on results of investigation of the actual damage and the numerical simulation, a suitable method for conservation of the site was proposed, which could provide a reference for similar masonry heritage conservation projects. The research indicates that appropriate measures should be taken to enhance the tensile strength of the wall corner during the restoration with plane turning points such as plate gates. Specific measures that could be taken for reinforcement include embedding stainless steel bars along the horizontal mortar joint.

Abstract:An ancient Banjing-river ship was excavated in an offshore river channel in Taicang. Desalination treatments are usually required before conservation and restoration work is carried out. In order to fully understand the salt content of the ship’s wood, the types and amounts of salts in samples from different parts and of different tree species were tested and analyzed. The results show that the insoluble salts contained in ship wood were represented by sulfur and iron compounds, with some containing FeS₂ (pyrite). The darkening of the ship wood is related to the iron ions in ship materials. The iron ions mainly come from iron nails on the ship and metal chelators are used to chelate and remove them. Through a comparative study of the effects of EDTAHO (EDTA-2Na and H₂O₂ compound reagent), EDTA-2Na and NaH₂PO₄·2H₂O soaking methods, the comprehensive effect of desalination using a 1 000 mL 0.4% neutral EDTA-2Na solution was the best. The iron ion concentration could be controlled within 1 mg/L after desalination twice in 44 days. Calculation of color difference (ΔE) using the L, a and b values of the samples obtained by a portable colorimeter after desalination showed the proximity to that of healthy material. The damage caused to synthetic cellulose and lignin was the least. In the end, EDTA-2Na was selected as the insoluble salt removal reagent for the ancient ship. The results of this study could provide favorable conditions for subsequent preservation work.

Abstract:An example of the spread of Chinese culture, Western parasols of the 19th—20th century, was mostly made of silk, with the handle being of ivory or other materials. The manufacturing process was characterized by the integration of Chinese and Western cultures. Thus parasols represent an important example of cultural exchange between the East and the West. At present, there are few studies and examples of parasol restoration in China. In our research, we took a 19th-century Western silk parasol collected in Hangzhou Arts and crafts Museum as an example. We carried out nondestructive analysis of fabric material and structure using a portable microscope and a near-infrared spectrometer. Restoration of the parasol was completed through technological research, production of support, parasol surface removal, leveling, restoration and assembly of the parasol surface. This paper is focused on the study of the shape decomposition of the restoration of parasol and the method for making the restoration mold, which is the key to the restoration of parasol and could provide a practical reference for the scientific restoration and protection of such cultural relics.

Abstract:Legal tender issued by the Central Bank of the Republic of China plays an important role in the history of Chinese currency, especially in the history of modern currency. During a period of fewer than 13 years from November 1935 to August 1948, more than a hundred versions of legal tenders with different denominations and designs were successively issued. They were printed by 16 different Chinese and foreign printing companies. A series of legal tenders issued in 1945 were studied using three-dimensional video microscopy, micro-Raman spectrometry (RS), portable X-ray fluorescence spectrometry (pXRF). The results indicate that organic pigments—C.I. Pigments Red 3,4 and 49:1—were used to print red serial numbers and other red patterns of the legal tender, while prussian blue, lead chromate and carbon black were used to produce most of the blue, green and brown colors. These results provide experimental data for the identification, conservation, restoration and research on paper currency and related civilizations.

Abstract:A landscape painting by Tang Yin is a silk scroll painting in Shanghai Museum collection. Time-honored as it is, the painting appears to be aged, damaged, incomplete and badly creased, and is in urgent need of restoration. A restoration plan was made strictly in accordance with the five procedures of ancient painting and calligraphy restoration, namely, “washing, uncovering, repairing, supporting and inpainting”. The restoration process also firmly adhered to the principles of “minimum intervention” “maximum information retention” and “safety”. Based on comparison of pictures before and after restoration, the restoration plan was found successful. Through constant practice, theoretical research and further discussion, the most suitable restoration method can be adopted for each cultural relic.

Abstract:The bronze drum, which has a history of more than 2 700 years, is an important instrument used in festivals, military events, weddings and funerals, sacrifices, ritual music and other oceasions in the southern minority areas. In order to make a scientific evaluation of the corrosion status and provide scientific guidance for the formulation of the technical route of protection and restoration of utensils and the development of repair work, the metallographic microscope, laser micro-Raman spoctrometer(RS) and environmental seanning electron microscope and energe dispersive spectrometer (ESEM-EDS) were used to analyze the metallographic structure, alloy composition and corrosion products of the seven bronze drums unearthed in Yulin area.The analysis results show that 1) the seven bronze drums are all cast and there is no forging and cold or hot working phenomena; 2) all seven bronze drums are made of a lead-tin bronze alloy which is characterized by low tin and high lead. The microstructure is a typical α-solid solution dendrite segregation. The tin content is between 6% and 12.2%, which is at the medium content level (5%≤Sn＜15%) and the distribution is more concentrated; the lead content is between 14.4% and 28.2% which is at the medium (10%≤Pb＜15%) to high (Pb≥15%) content level, and its distribution is also more concentrated. The proportion of high lead content in the alloy should be regarded as the proportion of craftsman’s intentional alloy; 3) the corrosion type of the bronze drums is α-solid solution copper-rich phase priority type. The preservation environment is mainly rich in oxygen and has less in chlorine. Corrosion products on the surface of the bronze drums are mainly green malachite,blue azurite and oxides,as well as a small amount of white lead. In conservation and restoration, the harmless rust could be retained without handling, but soil dirt mixed on the surface of the bronze drums needs to be cleaned and removed. Attention should be paid to storing in an oxygen-free environment.

Abstract:In order to identify the pigment composition and production process of Majiayao cultural painted pottery unearthed from Yangshan Cemetery (Banshan type) and Mapai Cemetery (Machang type) in Minhe County, Qinghai Province, we did a comprehensive analysis using polarized light microscopy (PLM), micro-Raman spectrometry, X-ray diffraction (XRD) and scanning electron microscopy-energy dispersive spectrometry (SEM-EDS). The results show that 1) the black color of Majiayao culture pottery in Qinghai is magnetite and hausmannite; 2) the red color is hematite; 3) the white color is quartz; 4) the Fe/Mn ratio in the black color shows an upward trend from 0.31 in the Banshan period to about 2.45 in the Machang period. The application of pigments from iron ore in the Minhe area is another example following the discovery of the Naka site in Hualong County. This discovery provides important clues for the study of the use history of mineral pigments on painted pottery in the prehistoric periods of Gansu and Qinghai areas. In combination with geological literature, it is speculated that the mineral pigments used in Minhe area of Qinghai Province were taken from the nearest areas. The pottery petrography facies are mainly composed of quartz, feldspar, hornblende and calcium carbonate; it is characterized by strong iron staining. There are many pores, with most elongated and directionally distributed. The pottery was sintered at about 900 ℃. On this basis, a comparative study on the composition of lithofacies of prehistoric painted pottery in Gansu and Qinghai areas and in-depth analysis of painted pottery trade and pottery provenance information will be made, so as to provide a reference for the research and conservation of the pottery.

Abstract:It is a common phenomenon that fresco surfaces are covered with soot in temples of Tibet. In this study, soot from a fresco surface of Samye Monastery in Tibet was studied by scanning electron microscopy (SEM), infrared spectrometry (IR) and cross-sectional analyses. The results show that the thickness of soot particles is about 80 μm, and that it consisted of saturated fatty glycerides or saturated fatty acids with amounts of carbon particles. The environmental testing results show that the burning of butter lamps causes volatile organic gases and particulate matters that badly exceed permitted levels.

Abstract:Synchrotron radiation (SR) is a special novel light source with a continuous spectrum ranging from far infrared, visible, ultraviolet to X-ray regions. In view of the advantages of high brightness, broad spectra and high polarization, SR-based technologies, especially X-ray technologies [X-ray fluorescence spectroscopy (XRF), X-ray absorption fine structure (XAFS), X-ray diffraction (XRD) and X-ray micro computed tomography (X-μCT)], have been broadly applied to the analysis and conservation of cultural relics and to archeological research. This paper summarizes relevant studies in China using existing SR-based X-ray devices for the study of cultural relics, and also compares prospects with frontier foreign research.

Abstract:Acrylic polymers have been widely used in the consolidation, bonding and sealing of cultural relics because of their various properties, such as film formation, high reversibility and hydrophobicity. Typical acrylic polymers (e.g. Paraloid B-72 and Primal AC-33) have a long history and a wide range of application in the conservation of cultural relics. However, considering the various materials and preservation conditions of different cultural relics, it is impossible to meet all the conservation requirements using only these popular materials. This paper reviews the application of other atypical acrylic polymers, including Paraloid B-44, B-48N, B-66, B-67, Primal SF-016, B-60A, MC-76, WS-24, and other emulsion acrylic polymers, to the conservation of cultural relics. The major chemical components, properties, advantages and disadvantages of the aforementioned materials are compared with regard to their different performances, the objects they are applied to, and methods and effects of these materials. By summarizing the history and current developmental trends, more alternates for the selection of acrylate materials for conservators in the future could be provided.

Abstract:This article concerns the fabrication techniques used for three damascened incense burners dating back to the Xuande period of the Ming Dynasty. Various non-destructive analytical methods, including X-ray fluorescence spectroscopy (XRF), scanning electron microscopy with energy dispersive spectroscopy (SEM-EDS) were used to determine the composition of the metal bodies and gold wires. Reflective light microscopy was used to study the distribution, density and also depth of the net pattern grooves on the surface of the ironware. The brown coating on the surface of a burner was identified as natural lacquer by Fourier transform infrared spectroscopy (FTIR). The information gathered was used to analyze the similarities and differences in fabrication techniques for these three burners and to explore the development of the fabrication techniques contributing to the properties of the incense burners.

Abstract:The clay stick model method was adopted in this study to discuss the special writing forms, reverse writing and inverted writing, in inscriptions, from the perspective of the manufacturing process. A set of inference models of leaf lettering was also built to further expound the reasons for forming of reverse writing and inverted writing under this model.