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1.
ABSTRACT

This paper analyzes the process of crack saturation, which is fundamental to understanding why panel paintings have survived remarkably well in the uncontrolled environments of historic houses or places of worship for several centuries. The process of crack saturation was analyzed using finite element modeling. A double layer elastic model with fractured overlying paint layer was subjected to uniaxial tension. The critical separation between cracks was determined and compared with patterns observed in real paintings. In addition, the generation and propagation of delamination were studied to elucidate the effect of their propagation on the saturation distance of cracks, as well as the load carrying ability of the paint layer. Contributing modes of crack propagation and their significance are also discussed. The results demonstrate that shearing fracture mode dominates the process of delamination. The impact of crack saturation on the degree of relative humidity variation that is allowable is also discussed.  相似文献   

2.
《文物保护研究》2013,58(1):46-53
Abstract

The collection of paintings by Velázquez in the Museo del Prado is important both because of the number of works — about 50 — and because of their quality and significance. It includes the Feast of Bacchus (The Drunkards), the Forge of Vulcan, Christ on the Cross, the Surrender of Breda (The Lances), the Fable of Arachne (The Spinners), Las Meninas and various royal portraits. Most of these works are in very good condition, which is essential for a proper study of the painter's technique and his development; in addition, since their source is the royal collection, they are well documented. Since 1982 most of the works by Velázquez in the Museo del Prado have been submitted to technical examination and to restoration. The technical studies included X-radiography, infrared reflectography, and analysis of the supports and materials, allowing us to establish the characteristics of each painting (technique, changes in composition, condition, history) and the development ofthe artist through the changes in his technique. Restoration consisted basically of consolidating the paint layers, moderate cleaning and the inpainting oflacunae. The only exception to the general good condition of the paintings was The Spinners, which presented a serious problem of craquelure and lack of adhesion in the paint layer.  相似文献   

3.
《文物保护研究》2013,58(4):173-194
Abstract

In the course of a program to develop adhesives for the consolidation of paintings it was found necessary to: (1) define the aims of the research, (2) design tests which would provide information on the mechanical performance (effectiveness) of the adhesives, (3) design tests which would help eliminate adhesives with qualities hazardous to paintings. This paper describes only the tests on the mechanical performance of various adhesives: (1) adhesion to paint films, (2) adhesion to conventional and newly developed lining supports, (3) cold flow of lining adhesives, and (4) rigidity of lining laminates. Formulations of the newly developed adhesives are given.  相似文献   

4.
《文物保护研究》2013,58(3):96-105
Abstract

Infra-red reflectography, a method of improving the detectability of underdrawings in medieval paintings, is discussed. It is shown that the results can be explained with the Kubelka-Munk analysis of the optical properties of paint films. Measurements are described providing a plot of the paint layer thickness required to hide an underdrawing, against the wavelength.

Such curves show a maximum around λ = 2.0 microns. Infra-red to visible image translation systems are surveyed to illustrate the choice of an infra-red vidicon television system to obtain reflectograms. This system is responsive to radiation up to 1.9 microns. The interpretation of infra-red reflectograms is briefly discussed. Limitations of the method are indicated.  相似文献   

5.
Moisture is a driving factor in the long-term mechanical deterioration of canvas paintings, as well as for a number of physico–chemical degradation processes. Since the 1990s a number of publications have addressed the equilibrium hygroscopic uptake and the hygro-mechanical deformation of linen canvas, oil paint, animal glue, and ground paint. In order to visualise and quantify the dynamic behaviour of these materials combined in a painting mock-up or reconstruction, we have performed custom-designed experiments with neutron radiography and nuclear magnetic resonance (NMR) imaging. This paper reports how both techniques were used to obtain spatially and temporally resolved information on moisture content, during alternate exposure to high and low relative humidity, or in contact with liquids of varying water activities. We observed how the canvas, which is the dominant component in terms of volumetric moisture uptake, absorbs and dries rapidly, and, due to its low vapour resistance, allows for vapour transfer towards the ground layer. Moisture desorption was generally found to be faster than absorption. The presence of sizing glue leads to a local increase of moisture content. It was observed that lining a painting with an extra canvas results in a damping effect: i.e. absorption and drying are significantly slowed down. The results obtained by NMR are complementary to neutron radiography in that they allow accurate monitoring of water ingress in contact with a liquid reservoir. Quantitative results are in good agreement with adsorption isotherms. The findings can be used for risk analysis of paintings exposed to changing micro-climates or subjected to conservation treatments using water. Future studies addressing moisture-driven deformation of paintings can make use of the proposed experimental techniques.  相似文献   

6.
《文物保护研究》2013,58(3):226-244
Abstract

This study describes the examination and analysis of four mixed media paintings from the 1960s and 1970s by Canadian artist Jack Chambers (1931–1978). The documentary evidence about his materials and methods is summarized and compared with the results of analysis of multilayer paint samples. The combination of Fourier transform infrared spectroscopy (FTIR) and gas chromatography-mass spectrometry (GC-MS) allowed the components of the paint media to be characterized: ortho-phthalate alkyd resins, iso-phthalate alkyd resins, drying oils, dammar, Pinaceae resin, and turpentine were identified in varying proportions. Many pigments and fillers were identified by FTIR and Raman and are enumerated. The effect that Chambers’ complex technique has had on the aging and degradation of the paintings is discussed. The severe cracking of the paint layers in one of the four paintings may be the result of a high proportion of dammar and turpentine diluent mixed with the alkyd paint and may also be related to the type of alkyd resin medium. Different history and environmental conditions may also be factors.  相似文献   

7.
《文物保护研究》2013,58(4):195-206
Abstract

The investigation of materials found in Bacon's studio is reported. The contents of the studio are examined and interpreted to identify the materials and colours most favoured by Bacon, and the range of media used. A small number of colours appear to have been heavily used. Some objects used as tools in the painting process are also investigated and explain textures seen in paint in his works. Samples of selected materials from the studio are analysed to identify the components of paints (pigments, extenders, and binders) used by Bacon. This investigation is part of a wider project examining his materials and techniques. The analytical information obtained here from the studio helps to clarify the statements made by Bacon in interviews regarding his use of materials and is proving useful in the identification of materials in his paintings, in order to help with the conservation and authentication of his works.  相似文献   

8.
《文物保护研究》2013,58(4):145-161
Abstract

For the study of Italian paintings and their techniques the examination of the binding media (glue, egg, oil) has considerable importance, but with the usual scientific methods of analysis the results have never been conclusive. Each sample may include more than one layer of paint and many constituents; egg yolk alone contains protein, oils, cholesterol. In the present project, in order to identify these diverse materials and also to eliminate interference from contamination (glue, wax or oil) used in later restoration processes, it was decided to mount original paint samples, including a bit of the ground, as cross-sections in a polyester resin embedding material and then to make the constituents visible under the microscope by using selective staining techniques. Only in this way could the foreign materials be distinguished from the original and the structure of the original layers be understood. Finally, other tests such as the fluorescent antibody technique and thin-layer chromatography could be applied to confirm the results of the staining. In removing over 500 specimens fronl paintings in the Walters Art Gallery precautions were taken to assure sample authenticity, and during the testing at the University of Michigan careful methods of standardization and control were devised, using both fresh and old samples of egg tempera and oil. Two stains, Ponceau S for protein and Sudan Black B for oil, provided the most workable means of identifying the binding media in the majority of the samples studied. A final report will have to await correlation of the material, but certain observations may be made at this stage: (a) 14th century, in primarily tempera paintings a limited use of oil was found associated with a specific green pigment, copper resinate; (b)15th century, the majority of the paintings were entirely of egg tempera, but layers containing oil in the underpainting or in the above-mentioned copper green occurred more frequently; (c)16th century, egg tempera was not replaced by oil, but both were used in a complex layering technique, the media varying layer by layer and area by area; (d)17th century, the mixed technique gradually declined, but egg tempera continued to be associated with the painting of flesh and occasional highlights.  相似文献   

9.
ABSTRACT

The impact of relative humidity (RH) and temperature variation on the mechanical behaviour of paintings on canvas was investigated, based on the various environmental recommendations that are applied by museums and institutions worldwide. Paint samples were constructed based on the works of twentieth-century artists such as Soulages and Riopelle. The various samples are based on criteria such as paint media, additives, pigment type, canvas type, thickness, type of application, and drying time. Once they are fully dry, paint films behave as elastic, viscoelastic, or viscoplastic materials depending on the chemical nature of their components. These properties, as well as tensile strength, were determined by a series of tensile tests. Other samples were included, originating from discarded oil paintings on canvas from the seventeenth and nineteenth centuries. To carry out mechanical tests under controlled conditions of temperature and RH, a climatic chamber was built around the column of a universal testing machine. Samples were submitted to stress relaxation tests to observe their response to changes in environmental conditions. RH was increased from 20 to 90% and temperature from 15 to 60°C. Reactivity diagrams were drawn based on the results. The endurance limit under mechanical fatigue was determined from the diagrams and helped define the risks associated with each painting type when exposed to the accepted environmental recommendations.  相似文献   

10.
《文物保护研究》2013,58(4):139-149
Abstract

The study of the structure and materials of ancient works of art has been much intensified with the development and use of improved analytical techniques. It was considered desirable to apply an X-ray fluorescence technique which could scan polished cross-sections of paint materials embedded in plastic. Layer thicknesses of 20–50 μ were successfully surveyed with an X-ray macroprobe attached to a fine-focus vacuum X-ray spectrograph. Elements above atomic number 16 in areas of 50 μ diameter were successfully detected and precisely located in the cross-section. The method has been applied particularly to the study of the technique of Rembrandt and Lievens paintings.  相似文献   

11.
none 《文物保护研究》2013,58(3):211-225
Abstract

The ageing of poly(vinyl acetate), PVAc, paints was assessed in works by Ângelo de Sousa and Joaquim Rodrigo. The materials and techniques of the artists were studied through interviews and by chemical analysis. They were both using PVAc in 1961, preparing their own paints by mixing commercial PVAc emulsions with selected colorants. It is shown that in most cases the emulsion employed was based on a PVAc homopolymer and that the paints are in good condition with no signs of deterioration. Finally, this study allowed a comparison to be made between paint samples aged naturally and those aged under artificial conditions. This means that these artificially aged samples may be used as reference materials for PVAc paintings. Both sets exhibit molecular infrared fingerprints that are undistinguishable from an unaged PVAc, suggesting little chemical degradation over 50 years of natural ageing.  相似文献   

12.
《文物保护研究》2013,58(1):9-20
Abstract

Deterioration of paintings is effected by chemical, physical and biological agents. Activity of these agents generates mechanical stresses which result in cracking, cupping, cleavage and flaking of the paint film. Internal mechanical stress appears to be primarily responsible for premature or drying cracks in paint. Stresses external to the paint cause age cracks which penetrate both paint and ground. The literature explaining the origin and characteristics of these cracks is reviewed. Although premature cracking can only be avoided by instructing the artist in proper use of materials, age or mechanical cracking can presently be prevented by environmental controls and careful handling. Present methods of reinforcement of paintings in general only partially stabilize them against environmentally generated stresses. Further research appears necessary for more complete understanding of the stresses old paint can withstand and of the forces exerted by the shrinking and swelling of textile and wooden supports. Search for and testing of more physically and chemically inert support materials are suggested.  相似文献   

13.
《文物保护研究》2013,58(3):134-142
Abstract

Naturally occurring pigments used by Aborigines in rock paintings have been collected in Western Australia. They area red pigment (mainly hematite, Fe2O3)(from a red ochre mine worked until historic times by Aborigines, and a white pigment (huntite, Mg3Ca(CO3)4) which is still collected and used by Aborigines. Samples were also taken from rock paintings in which these pigments were used or were thought to have been used. The pigment samples were analysed to establish chemical, mineralogical, and physical properties. The paint samples were examined microscopically and with an electron probe to study their relationship with the rock surface and with other paint layers. The relationship between the pigments’ properties and their durability is discussed.  相似文献   

14.
ABSTRACT

Twentieth century paints often contain titanium dioxide and zinc oxide based white pigments that can range from photostable to highly photocatalytic. Photocatalytic pigments can cause the degradation of paint upon UV exposure, whereas photostable pigments may be benign or can protect paintings from degradation. Hence, knowing whether or not a pigment is photocatalytic is of high importance for risk assessment and the subsequent decision making process concerning storage and exposure conditions of objects. Here we present a proof of principle, focused on titanium white paints, for an easy-to-use and low-tech application of a commercial photocatalytic activity indicator ink (PAII) on embedded paint samples or cross sections. This test determines, qualitatively, if a photocatalytic pigment is present in a white paint sample. The PAII paint sample staining application shows an obvious color change, within five minutes of UV irradiation, for paint samples containing photocatalytic pigments. A microscope with a camera and a UV source are the only necessary equipment for the application of this method. A quantitative image processing protocol is also proposed as an extension of the staining method by applying open source software analysis to measure the color change using photographs. The test was evaluated on reference paints with well-characterized pigments and applied on samples from modern paintings by Piet Mondriaan, Robert Ryman, and Lucebert, indicating the presence of harmful photocatalytic pigments in these cases. The novel application of a commercial ink on paint samples offers a simple test, not just for assessment of photocatalytic activity of titanium white pigments, but which may in future be applied for the detection of photoactive forms of zinc white and other potentially harmful semiconductor pigments in art objects.  相似文献   

15.
《文物保护研究》2013,58(3):216-230
Abstract

The surfaces of acrylic emulsion (dispersion) paint films were investigated by atomic force microscopy (AFM), with supporting chemical information provided via infrared spectroscopy. The morphological and chemical features of the surfaces of a series of recently cast reference paint films were explored, including characterization of changes induced by exposure to water and mineral spirits. A portable in situ AFM system was also used to document the surfaces of acrylic emulsion paintings in Tate's collection. The complete and partial removal of migrated surfactant was successfully imaged alongside features arising from mechanical action. Differences in paint surfaces and migrated surfactant layers were observed in relation to pigment type, paint brand and exposure to accelerated ageing, in addition to applied wet surface cleaning treatments. The findings contribute to further understanding of the subtle changes occurring at acrylic emulsion paint film surfaces and are relevant to current debates on the removal/disturbance of original surface surfactant from these films through conservation treatment.  相似文献   

16.
《文物保护研究》2012,57(1):14-27
ABSTRACT

Zinc (carboxylate) soaps, formed by reactions between zinc oxide (ZnO) and fatty acids in a drying oil, are known to cause deterioration in the paint layers of modern and contemporary oil paintings. This study investigates zinc carboxylates that developed in an oil painting test panel designed to mimic the aging and degradation encountered in actual works of art. Following accelerated and natural aging, protrusions were noted on the surface of the test panel. A large protrusion with erupted gel features was extracted from the test panel, mounted in top view, and then cut to reveal the sample's cross section. The gel features, which resulted from the unreacted oil binder's separation from the paint matrix, facilitated zinc carboxylate formation. Using reflectance µ-FTIR and SEM-EDX analysis, the morphologies and spatial distributions of zinc carboxylates within the gel regions of the protrusion were studied. A concentration gradient of zinc within the gel material was observed in the cross-sectional view, indicating patterns of zinc carboxylate formation and migration.  相似文献   

17.
none 《文物保护研究》2013,58(3):157-184
Abstract

The treatment of flaking pigment on two paintings, one on ceramic and the other on glass, is described; a brief history of painting on glass and ceramics places these works in context. The treatments are discussed in relation to other types of treatment for paintings on similar rigid supports. The longevity of the conservation methods used is discussed, as are the results of re-examination of the objects some years after the completion of the treatments.  相似文献   

18.
《文物保护研究》2013,58(4):207-217
Abstract

Materials from 38 paintings by Francis Bacon (1909–1992), including 21 complete works and 17 partially destroyed canvases are investigated. Observations are made of the artist's technique and details are compiled of the supports used. Samples of paint and priming were taken for analysis using polarized light microscopy, Fourier transform infrared spectroscopy (FTIR), gas chromatography–mass spectrometry (GC–MS), pyrolysis–GC–MS (Py–GC–MS), and scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM–EDX). Analysis of priming layers appears to show that the priming composition correlates well with particular ranges of dates. A fairly limited range of materials are found, with many of the same pigments found in works spanning Bacon's career, though other pigments were introduced at different stages in his career. Oil paints were used consistently for the painting of figures, but household paints were increasingly used in backgrounds from the 1960s onwards. A variety of different synthetic media are found in later works, including household acrylic paints and spray paints. Increased knowledge of Bacon’s materials is expected to be of great value to conservators caring for the work of this highly significant artist, and is already helping in the authentication of works attributed to him.  相似文献   

19.
An assemblage of Buddhist wall paintings and sculptures dating to the twelfth/early thirteenth century are found distributed over the interiors of the temple complex at Sumda Chun, Ladakh. Detailed investigations carried out as part of a conservation project shed light on their antiquity and production technology. The sculptures are constructed with fine mud mortar applied over a wooden armature and affixed to the walls without any support from the ground. In both the sculptures and wall paintings, the paint layer is applied over a thin gypsum ground that functions as a white colourant where unpainted. For the paint layer, azurite, vermilion, and orpiment are the dominant mineral pigments utilized. Minium (red lead) has been used for preparatory drawings and as paint. Highlighting of special areas was achieved using a laminate of tin–lead alloy and gold on relief. Overall the material and techniques employed in the execution of the wall paintings and sculptures are consistent with those reported for other early sites in the region.  相似文献   

20.
none 《文物保护研究》2013,58(4):277-283
Abstract

Various copper compounds which were used as pigments have been identified in a study of the layer structure of paintings. These pigments were either obtained from natural minerals or were synthesized. The results of attempts to synthesize copper-based pigments by following old recipes are also presented; the man-made pigments are compared with those found in paintings and with natural copper minerals of identical composition. The historical use of synthetic copper-based pigments is discussed.  相似文献   

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