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1.
《文物保护研究》2013,58(3):216-230
AbstractThe 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
2.
《文物保护研究》2013,58(2):143-144
AbstractOil paints dry by polymerization. This 'drying' process may be substantially complete and the surface of the paint film dry to the touch within weeks, but measurable changes continue for years. Other, slower processes also continue, primarily hydrolysis of glyceride esters. This produces carboxylic acid groups as either free fatty acids (in the case of acid groups that have not reacted otherwise) or acid groups bound to the crosslinked oil matrix (in the case of acid groups that have engaged in polymerization reactions). These may react with pigments to form carboxylate salts (called soaps in the case of a fatty acid). These changes affect the physical properties of the paint and the way that conservation treatments affect it. This paper examines the extent of hydrolysis and soap formation in some naturally aged drying oil and paint films, the extractability of these materials in organic solvents, and measured and predicted changes over time in the physical properties of naturally aged paint films. Long-term physical and mechanical changes due to aging are minor compared to those produced by overcleaning or excessive exposure to heat. 相似文献
3.
《文物保护研究》2013,58(3):183-186
AbstractA yellowish copper vanadate mineral has been found in Swedish mural paintings from the fifteenth century. Small patches occur in malachite-green paint. Thirteen samples from five churches have been analyzed by optical and scanning electron microscopy with energy–dispersive X-ray spectrometry, transmission electron microscopy, X-ray powder diffraction, and polarized light microscopy. The substance is evidently the rather uncommon mineral volborthite, with the chemical formula Cu3V2O7(OH)2.2H2O. Very small quantities have also been noted for another mineral, presumably calcio-volborthite, CaCu(VO4)(OH), also named tangeite. The results show that the conservator should always be observant for pigments not earlier noticed or reported. There are some old mines in Central Europe, e.g. in Germany, which contain malachite as well as copper vanadate minerals, and this is probably the origin of the yellow patches in the paintings. 相似文献
4.
《文物保护研究》2013,58(3):96-105
AbstractInfra-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.
《文物保护研究》2013,58(4):217-226
AbstractMany natural and synthetic products have been used for the consolidation of paint layers, but none have been thoroughly tested for this application. This is apparent for most of the synthetic and semi-synthetic adhesives for conservation, many of which are pure polymer resins and dispersions adapted from other industries. They were not specifically formulated with the appropriate properties for conservation, nor do they take advantage of some of the more recent developments in adhesive technology. BEVA® 371 is unique among adhesives used for consolidation treatments, as it is a multi-component mixture and was designed specifically for the conservation field using the best technology available at the time. However, the main focus of the research was its application as a lining adhesive. Thus, optical properties and stability, specifically color stability, were not thoroughly evaluated even though some lining applications that were first recommended could have benefited from this type of investigation. This paper will discuss the development of BEVA® 371, the chemistry, and roles of each component, and address a practical concern about the tack behavior of its replacement formulation, BEVA® 371b. 相似文献
6.
ABSTRACTThis 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
7.
《文物保护研究》2013,58(4):173-194
AbstractIn 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
8.
To date, a limited number of aqueous conditions have been tested experimentally as potential cleaning reagents on modern acrylic paint films. Those assessed have tended to extract measurable quantities of paint film components and distort the paint films physically. In this paper the results of a series of experiments designed to examine pH, conductivity, and specific ion effects of potential aqueous cleaning solutions on a series of commercial acrylic paints are reported. A three-dimensional microscopic technique was used to characterize the physical (volume and surface roughness) changes and liquid chromatography-tandem mass spectrometry was used to characterize the chemical (extracted surfactant) changes following paint film exposure to the aqueous solution. The tested paint films in this study clearly exhibit an isotonic point below which swelling and extraction is significant, and above which the swelling and extraction is diminished. Manipulation of conductivity and the ionic species in solution can reduce both the physical film changes and surfactant extraction from acrylic paint films; while pH appears to be of limited use in controlling aqueous cleaning effects. Moreover, there seems to be a specific ion effect for both swelling and de-swelling in acrylic paint films that can be rationalized through the Hofmeister Series. 相似文献
9.
ABSTRACTThe 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(3):134-142
AbstractNaturally 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
11.
ABSTRACTConservation of an oil painting on a zinc support is a complex challenge that has not been covered in the literature. Oil paint and zinc support rarely form a working combination because of their chemical properties. This article discusses the conservation of an oil painting on a zinc support that was found in extremely bad condition due to harsh environmental conditions it had been exposed to. The object had to be consolidated due to flaking paint and cleaned of surface dirt and support corrosion products. Finally, the object had to be physically strengthened due to the weakness of the support. This process required conservators to combine methods from several different fields of the conservation discipline. Methods employed in the conservation process came less from the literature, due to the lack thereof, and more from the everyday experience of the department and vernacular working practices. The overall methodology of the process has been reconstructed and critically evaluated in the broader field of conservation ethics and the discipline as a whole. 相似文献
12.
《文物保护研究》2013,58(3):185-193
AbstractThe two Stangengläser, tall cylindrical vessels from the beginning of the seventeenth century, are described in detail. The severely damaged Stangengläser, decorated with diamond-point engraving and cold-painting, were challenging to treat. Research preceding the conservation revealed differences in decorating techniques. Samples of the paint layers were analyzed using micro-Fourier transform infrared spectroscopy. Two layers of resinous varnish with a middle layer of paint containing a plant gum were found on the Stangenglas with Allegory of Caritas and Zierotin coat of arms. In the plain paint layer of the Stangenglas with dancing couples, egg white was identified as the binder. The glasses, analyzed using scanning electron microscopy with energy dispersive X-ray spectrometry, had similar potash–lime–silica compositions, which seems to be characteristic for glass from Bohemian lands. Results of analysis contributed to the discussion about the possible provenance of the Stangengläser, the glassworks at Wilhelmberg, South Bohemia. 相似文献
13.
《文物保护研究》2013,58(1):22-26
AbstractVery small paint samples from Cosimo Tura's ‘The Annunciation with Saint Francis and Saint Louis of Toulouse’ were submitted to amino acid analysis in order to determine the nature of the binding media. The four panels appeared to have been painted with egg tempera, and showed extensive localized deterioration in the blue areas but not in the other coloured areas. Following the Picotag method, the samples were hydrolyzed in an acid vapor, derivatized with iso-thiocyanatobenzene, and analyzed using reversed phase high pressure liquid chromatography (HPLC). Amino acid analysis demonstrated that the red and brown areas were painted using egg yolk as the binding medium, while the blue areas were painted with animal-skin glue (distemper). Analysis of the green paint indicated a mixture of egg yolk and glue. The use of these techniques makes it possible to identify proteinaceous materials in art objects from samples in the microgram range. 相似文献
14.
《文物保护研究》2013,58(4):207-217
AbstractMaterials 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
15.
《文物保护研究》2013,58(4):195-206
AbstractThe 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
16.
17.
《文物保护研究》2013,58(1):46-53
AbstractThe 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
18.
It has often been observed anecdotally and implied through experimentation that acrylic emulsion paintings accumulate and entrain soils over time due to the inherent mechanical softness in artist's acrylic paint films, through the presence of hydrophilic film components, and by virtue of the ubiquitous presence of surfactant moieties on these film surfaces once they dry. In the present study, it has been this last effect that we have sought to describe more fully in terms of surfactant responsiveness to both temperature and relative humidity (RH). Surfactant hydration and dehydration under varying temperature and RH conditions affects the ultimate partitioning of the surfactant at the paint–air interface, as well as the inherent size, aggregation tendencies, and solubility of surfactant in the bulk paint materials which contain components that are highly responsive to changes in temperature and RH (e.g. polyacrylic or polymaleic anhydride-type dispersal materials). In this work, analytical techniques including three-dimensional microscopy and quartz crystal microbalance with dissipation were used to add to and reinforce current understanding of the physical and mechanical changes to acrylic paint films with temperature and RH. The migration of surfactant at the film surface was studied using desorption electrospray ionization-mass spectrometry and attenuated total reflectance Fourier transform infrared microscopy. 相似文献
19.
《文物保护研究》2013,58(3):151-154
AbstractUsing the Kubelka and Munk formula (and in the absence of adequate experimentally determined data, hypothetical values), the effect of age-induced increase in the transparency of oil paint IS shown to produce distortions in the rendering of forms when the thickness of the paint and dark grounds or underpainting are the basis of the artist's technique. 相似文献
20.
《图书馆管理杂志》2012,52(3-4):304-312
ABSTRACT During the past decade we have noted a marked increase in the use of special collections materials in the university classroom. This presents the library with an opportunity to assert its role as a unique and irreplaceable contributor to the University's core mission. Asserting this is predicated on the assumption that an instructor's goals will be met, that students will become successful researchers, and that library staff will survive the encounter. This is not easy to accomplish and this article is an attempt to describe those elements that we have found to be central to a successful instructional outcome. 相似文献