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1.
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   

2.
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   

3.
《文物保护研究》2013,58(4):269-277
Abstract

simple mathematical model is presented that predicts the decay time of the internal relative humidity (RH) of backboard-protected canvas paintings when subjected to external RH fluctuations. The model takes into account the permeance of the canvas and the hygroscopicity of the enclosed materials. Predictions from the model are tested experimentally. The wooden stretcher releases moisture more slowly than expected, providing less buffering than predicted by the model. The practical implications of these findings are discussed.  相似文献   

4.
《文物保护研究》2013,58(1):76-80
Abstract

The reasons for the often poor condition of Viceregal paintings and sculptures are examined. The conservation of four works is described, chosen largely because they had typical problems and would benefit from recently developed techniques. The treatments were: the preliminary lining of very cupped paintings, before using moisture to stretch the original canvas and allow the paint layer to lie flat again; lining badly torn paintings on a thin, semi-rigid, transparent support and using the old stretcher, in order to preserve the structure and aesthetic impression of the painting as much as possible; masking to protect susceptible fine lines against solvent action during cleaning; blending disturbing passages of the paint layer like blanching, irreducible stains, singeing and pentimenti into the colour scheme without overpainting; repairing broken pieces of sculpture with bamboo dowels. The study is accompanied by an iconographical discussion of colonial works of art.  相似文献   

5.
ABSTRACT

Panel paintings are essentially wooden boards painted on one side. Due to the vapor resistance of the paint layer, changing ambient conditions lead to exchange of moisture on only one surface. Subsequently, a non-uniform moisture content profile is formed across the thickness of the board. As a result, differential expansion causes the board to bend in case of no mechanical restriction, or it leads to a build-up of stresses inside the material if restrained. Experiments with oak boards sealed on one side and exposed to a change in the ambient relative humidity (RH) were performed. By scaling, the response of any board with different thickness can be predicted. Since the bending of the board can be described as a linear system behavior, the frequency response can be predicted based on the step response. In combination with critical strains for wood and gesso from the literature, this gives insight into allowable RH fluctuations in terms of frequency and amplitude for different board thicknesses.  相似文献   

6.
《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   

7.
《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   

8.
《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   

9.
Mark Rothko's Harvard Murals are a series of paintings on canvas commissioned by Harvard University and created in the early 1960s. The present study investigates Rothko's creative process, materials, and technique with ultraviolet and infrared imaging, analytical chemistry, cross-sectional analysis, and comparisons with the literature. Infrared and Raman spectroscopy imaging of cross sections help with the chemical mapping of the paint stratifications. A comparison of paper studies, studies on canvas, and the final five works installed give a detailed insight into Rothko's editing process. The intimate relationship between works on paper and canvas is traced by uncovering a back and forth between the two media, and the mixing of dry pigment with binder is a common theme for works on both supports. Motif developments, changes, and distinct painting campaigns become apparent with ultraviolet induced visible fluorescence imaging and infrared reflected infrared digital photography. Color measurements and microfading experiments give insight into the stability and light sensitivity of the materials used by Rothko in the Harvard Murals.  相似文献   

10.
Funori is a polysaccharide-based adhesive extracted from seaweeds and is generally used in the conservation of easel paintings for the consolidation of matte paint. It is appreciated since it does not change the optical properties of the consolidated materials and its mechanical properties do not change with ageing. Because of these characteristics, this research focused on the evaluation of Funori as a suitable material for the consolidation of powdering paint layers in wall paintings. Tests were carried out where Funori was applied onto painted plaster replicas, which were then artificially aged and investigated in order to evaluate the material's behaviour according to the specific properties and conditions of wall paintings. The effectiveness of the consolidation was evaluated from the point of view of adhesive power, as well as the interactions of Funori with some physical properties of the consolidated painting, such as colour and water vapour permeability and, therefore, its resistance to accelerated ageing and biological colonization. In addition, the behaviour of Funori applied on plasters contaminated with soluble salts, a frequent condition in wall paintings, was also evaluated.  相似文献   

11.
《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   

12.
《文物保护研究》2013,58(4):237-253
Abstract

The requirements for, and assessment of, suitable fabrics for artist canvas and for the structural reinforcement of easel paintings on canvas are presented. Crucially, the aesthetic and kinaesthetic, as well as physical properties of the canvas fabrics have been taken into account. To evaluate the fabrics the following properties were measured: stiffness, ultimate tensile strength, moisture response, crimp, drape, and lustre. Fabrics investigated include cotton, linen, polyester, polyamides, and carbonized fibres. Although polyester is yet to match linen or cotton kinaesthetically or aesthetically, overall it exhibits the best combination of properties. However, the results have shown that even when raw fibre material has suitable properties the finished woven fabric may not. This is because of the strong influence of the woven geometry on the final behaviour. It has been found that drape and lustre are very good properties to quantify some aspects of the feel and look of fabrics, in the context of conservation, and to provide a common language to ensure that the specification incorporates these aspects.  相似文献   

13.
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   

14.
《文物保护研究》2013,58(2):85-94
Abstract

The role of colourmen’s canvas stamps in dating paintings is discussed. A series of 16 Winsor and Newton canvas stamps is illustrated in conjunction with a dating table, the resulting system being of practical use for dating paintings bearing Winsor and Newton canvas stamps.  相似文献   

15.
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   

16.
《文物保护研究》2013,58(4):167-171
Abstract

A miniature low-pressure apparatus for localized treatment of paintings is described. Alternative working surfaces are available which allow heat and moisture treatment on canvas paintings without removal from their stretchers. Other applications of the apparatus are discussed.  相似文献   

17.
ABSTRACT

This article describes how to build, in-house, a new type of ultrasonic nebulizer and presents the results of tests to determine its rate of aqueous flow and its performance during the transport of a collagen-based adhesive (ratio of adhesive actually delivered to adhesive misted). It also reports on a consolidation treatment case study carried out with the new ultrasonic misting prototype: the NebulA-MG 14. This case study was applied to powdery paint layers of a medium-sized oil painting on canvas, 111.5?×?86.5?cm. The new device is shown to be both reliable and effective, particularly for consolidating medium and large-sized works.  相似文献   

18.
《文物保护研究》2013,58(4):209-214
Abstract

Well-cleaned canvas fibres from two oil paintings have been dated by radiocarbon. Although the dates agree with the expected ages of the paintings to a first approximation, uncertainties in the date arise from ambiguities (or ‘wiggles’) in the calibration curve. Only by introducing additional information about the paintings into the calculations can more precise results be obtained. Two paintings have been dated in this way, using the radiocarbon dating technique in conjunction with dendrochronological and art historical information.  相似文献   

19.
《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   

20.
《文物保护研究》2013,58(2):76-91
Abstract

The study focuses on the range of pigments and media that the Italian artist Lucio Fontana (1899–1968) employed for selected works dating between 1949 and 1968. Samples were taken from ten groups of works, all on canvas support, as well as from painting equipment that survived in the artist's former two studios. Techniques of analysis used were pyrolysis-gas chromatography–mass spectrometry for media identification, and laser desorption ionization time-of-flight mass spectrometry and Raman microspectroscopy for pigment identification. Fontana's reputation as a daring and experimental artist, best known for his group of slashed paintings called tagli, is seen to correspond with certain unusual material choices he made. The study also points to several links that exist between seemingly unrelated cycles. These links are, among others, based on experiences with in part novel media such as oil, alkyd, polyvinyl acetate, acrylic, acrylic–vinyl, and mixtures of them. With regard to pigments, the selection of samples showed that they were mostly of a synthetic organic nature.  相似文献   

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