共查询到20条相似文献，搜索用时 140 毫秒
1.
《文物保护研究》2013,58(4):176-188
AbstractThe non-saponifiable fractions of the principal drying oils have been examined by gas and thin-layer chromatography and found to be qualitatively similar though varying in the relative amounts of sterols present. In the case of aged paint films it has been found that these sterols have largely disappeared from unpigmented films and those containing light red and lead white as pigment, though they survive quite well in the presence of verdigris. Similarly cholesterol was not found to survive well in egg tempera films. Doubt is felt as to the value of such analyses as an approach to paint medium identification. 相似文献
2.
《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
3.
《文物保护研究》2012,57(1):14-27
ABSTRACTZinc (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
4.
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
5.
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
6.
《文物保护研究》2013,58(3):231-249
AbstractThis paper presents a comparative investigation of recovery procedures for the analysis of natural organic colorants, encompassing ten major natural organic dye chemical classes, several sample types (silk, wool, cotton, pigment, paint), prepared from the extracts of twelve biological sources, and nine different recovery protocols. These protocols are based on the traditional harsh hydrochloric acid method; on mild hydrolysis methods involving formic, oxalic or hydrofluoric acid; and on methods consecutively employing mild and harsh hydrolysis on the same sample. An evaluation system was developed by classifying analytical results in an upper, middle or lower grade with reference to the best result obtained. This classification was used to calculate scores for each hydrolysis method and for either textile (silk and wool or cotton) or pigment/paint. The best overall hydrolysis method for textile samples was a combination of mild oxalic acid with traditional hydrochloric acid hydrolysis. The best overall hydrolysis method for pigment/paint was a combination of a newly modified mild hydrofluoric acid treatment with traditional hydrochloric acid hydrolysis. The application of these methods to historical samples will not necessarily give the optimal result achievable for every biological source, but will definitely reduce the risk of missing essential information for the elucidation of ancient technology in a geographical and historical context. The reduced level of risk will avoid repetitive sampling and reduce the level of invasiveness, hence taking into account good conservation policies. The potential of these selected methods is illustrated with the analysis of some historical Chinese textile and paint samples. 相似文献
7.
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
8.
《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
9.
AbstractThe 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
10.
AbstractThe painting materials used by Lucio Fontana were investigated through the analysis of 28 Spatial Concept works created between the early 1950s and the artist's death in 1968. The pictorial media were analyzed by means of numerous techniques including Fourier transform infrared spectroscopy, pyrolysis-gas chromatography–mass spectrometry, scanning electron microscopy, and X-ray fluorescence. This study has provided a more complete understanding of the artist's technique, as it was found that Lucio Fontana had already begun experimenting with new synthetic pictorial and binding media such as alkyds and polyvinyl acetates at the beginning of the 1950s, and polyesters during the early 1960s. Although he never abandoned the use of commercial oil paints, Fontana's application of these new materials continued in an infinitely varied search for innovative expressive effects. The characterization results explain the physical and mechanical properties of the paint layers, and may be correlated with the conservation state of the works analyzed. All the results have been compiled and are discussed together with the artist's practices and their evolution over time. 相似文献
11.
《文物保护研究》2013,58(4):212-221
AbstractWood, particularly in the presence of excessive moisture, deteriorates due to action of biological agents and sunlight. Decay manifests itself not only in impairment of physical strength but also in discoloration. Protection of the paint during consolidation by impregnation and polymerization, albeit difficult, is possible. Details of a home-built 23 cm-diameter and 48 cm-long chamber for vacuum impregnation are given. The permeating methylmethacrylate monomer solution used with good results contained bis-4-t-butylcyclohexyl peroxidicarbonate as catalyst, and pyridine as activator in addition to methylmethacrylate polymer, which reduced the rate of heat generation by the reaction. Polymerization induced by gamma irradiation also yielded satisfactory results. Case histories of three artifacts are described. 相似文献
12.
Marine Cotte Emilie Checroun Wout De Nolf Yoko Taniguchi Laurence De Viguerie Manfred Burghammer 《文物保护研究》2017,62(1):2-23
The origin(s) and role(s) of metal soaps in paints are a worldwide concern today. These hybrid compounds, containing both fatty acid chains and metals associated with a carboxylate function, are increasingly identified in paints. As reviewed in the first part of this work, the presence of metal soaps in paints is differently interpreted in scientific publications: metal soaps are sometimes considered to play a positive role as anchor points, during paint drying processes; they can also be considered as responsible for many degradation processes (protrusions, efflorescences, darkening, etc.). Their origins are also interpreted in various ways. In some paintings (in particular from the twentieth century), they have sometimes introduced on purpose, as additives, to modify the physical properties of the painting materials. In older paintings, metal soaps are usually thought to result from an uncontrolled reaction of oil with lead-based pigments, in particular lead white, red lead, and lead tin yellow. In the second part of this work, the review of historical recipes of lead-based paint shows an important number of recipes based on controlled mixing of oil with lead driers. In the third part, the experimental reproduction of such traditional recipes using walnut oil and litharge (PbO) shows that lead soaps can be formed, both in about one hour at ～100°C, or in about one month at room temperature. It shows as well that after a few years, litharge is no longer detected in the paint medium, while different lead carbonates are. Finally, the micro-infrared spectroscopy and micro-X-ray diffraction re-analysis of protrusions from a nine-year model painting shows together with lead soaps, the presence of Pb5(CO3)3(OH)2O (‘synthetic plumbonacrite’), an unusual phase recently observed in a protrusion from a painting by Vincent Van Gogh. This work highlights (i) the multiple origins and roles of metal soaps in paints and (ii) the importance of combining the analysis of fragments from historical paintings with the analysis and reproduction of historical recipes. In particular, we show that the components detected today in historical paintings may severely differ from those originally used or prepared by the painter, complicating the assessment of the painter's intentions. More than the presence of metal soaps, the key questions to be tackled should be about their origins and (re)mobilization. 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.
Ann Marlene Gagnon 《文物保护研究》2013,58(8):435-447
ABSTRACTThis 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
15.
《文物保护研究》2013,58(1):9-20
AbstractDeterioration 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
16.
《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
17.
《文物保护研究》2013,58(3):186-203
AbstractSafflower red was prepared by extracting safflower petals (carthamus tinctorius L.) at alkaline pH, after the preliminary removal of water-soluble safflower yellow. Alkaline extracts were used to prepare dyed silk, wool, cotton and paper, to precipitate the pigment, to prepare paint and to produce the antique Chinese cosmetic rouge. All reference samples were analyzed with high-performance liquid chromatography–photodiode array–mass spectrometric detection (HPLC-PDA-MS) after colorant was removed from its substrate by both a harsh and mild acid hydrolysis method. In addition to the red colorant carthamin, four colorless components are markers for safflower. These components were characterized by their retention times, ultraviolet–visible (UV-Vis) spectra and mass spectra and were given the codes Ct1, Ct2, Ct3 and Ct4. Experiments on references clearly indicated that these Ct components, unlike carthamin, withstood harsh acid hydrolysis as well as light-induced accelerated ageing, and that they could be found even in a completely faded wool sample. This made them excellent markers to identify safflower red, even in discolored historical samples or in samples that must be treated in a way that destroys carthamin. These findings may contribute to a better understanding of the manufacturing technology and to better conservation of objects that have already undergone considerable light-induced ageing. 相似文献
18.
《文物保护研究》2013,58(3):195-208
AbstractPyrolysis–gas chromatography was applied to the characterization of synthetic organic pigments. On pyrolysis, azo pigments and phthalocyanine blue yield characteristic fragments. These pyrolysis products were identified, and the mechanism of decomposition was studied. In the case of paint samples, the main pyrolysis products derive from the medium, although the presence of additional peaks enables azo pigments and phthalocyanine blue to be characterized. Some examples of the analysis of artists' paints are given and the peaks are identified. The main limitation of this technique is that it is impossible to detect chemically and thermally stable pigments, or inorganic components. 相似文献
19.
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
20.
《文物保护研究》2013,58(3):199-210
AbstractDescente des vaches (1836) by Théodore Rousseau in the Mesdag Collection in The Hague is barely readable and its paint layers are in poor condition. The surface of the painting is strongly deformed and cracked, the whole painting has darkened and especially the greens have lost all or most of their colour resulting in brown passages. Large passages of the painting that were painted with multiple thick and medium-rich layers have darkened dramatically. This paper proposes that the degradation of Emerald green (Cu(C2H3O2)2·3Cu(AsO2)2, copperacetoarsenite) – the main green pigment used in this painting – is a significant factor in the cause of the darkening. Electron backscatter images reveal that the Emerald green particles are shown different degrees of degradation: from partially to completely disintegrated. Elemental maps show that arsenic is distributed throughout the paint cross section, with relatively higher concentrations around iron- and aluminium-containing particles, and in the varnish layer. Imaging-Fourier-transform infrared microscopy detects copper soaps in the degraded Emerald green-containing layers. Analytical data from four paint cross sections strongly suggest that Emerald green reacts with free fatty acids derived from the binding medium forming copper soaps and mobile arsenic-based species. Chemical laboratory experiments fully support this hypothesis. Emerald green and palmitic acid in chloroform form copper palmitate and arsenic trioxide (arsenolite, cubic) under room temperature and normal light conditions. The degradation of Emerald green particles in Descente des vaches has resulted in a loss of light-reflecting surfaces and in newly formed compounds in the paint, both contribute to the colour change from green to brown. 相似文献