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1.
《文物保护研究》2013,58(3):156-159
AbstractA blue pigment frequently found in Cuban colonial decorative wall paintings from about 1750 to 1860 has been identified with the aid of thin-layer chromatography, IR spectrometry, X-ray diffraction, thermal analysis, scanning electron microscopy and X-ray microanalysis as ‘Maya blue’. This is the first reported occurrence of Maya blue from a period after the conquest and in a non-Mayan cultural area. 相似文献
2.
AbstractVarious 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
3.
《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
4.
Unvarnished twentieth-century oil paintings are often sensitive to aqueous swabbing, a method routinely employed by conservators for surface cleaning. This study proposes a connection between sensitivity and the presence of magnesium sulphate heptahydrate which has been identified on the surface of some of water-sensitive paintings. The probable source of magnesium is magnesium carbonate, an additive in some twentieth-century oil paints, which has reacted with atmospheric sulphur dioxide (SO2). Films made using modern manufactured paints and formulations made in the laboratory were exposed to gaseous SO2 and raised relative humidity and examined using scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray diffraction to characterize the crystalline entities. Films containing magnesium carbonate formed magnesium sulphite and sulphate hydrates. Films containing zinc oxide were also investigated. These formed zinc and sulphur containing salts. Sensitivity to swabbing with water before and after exposure was evaluated. Films that developed salts, demonstrated increased sensitivity to aqueous swabbing after exposure to SO2. Findings suggest that increased water sensitivity may be due to a combination of the formation of hygroscopic degradation products and to weakening of the paint film due to salt-induced disruption of the surface. 相似文献
5.
Discoloured 18-carat gold decorations from Sweden have been analysed by scanning electron microscopy with energy dispersive X-ray spectroscopy and X-ray electron spectroscopy (XPS)/electron spectroscopy for chemical analysis (electron spectroscopy).The original gold composition was close to 75% gold, 13% silver, and 12% copper. After manufacture, many details were boiled in sulphuric acid. As a consequence of this, the surfaces are irregular and porous with a gold concentration around 90% and with less than 1% copper. With XPS the outermost 10–20 atomic layers could be examined. No copper was present here, and the silver concentration was significantly higher. Also carbon, sulphur, oxygen, and (in one case) chlorine were present. The valence numbers indicated that gold only occurred in its metallic state, while silver (as Ag+) was preferably associated with sulphur to form black silver sulphide (Ag2S). The grey discolorations are basically due to silver sulphide and organic dirt. Sometimes green, violet, and ‘copper-shining’ colours occur, presumably as a result of light refraction phenomena. 相似文献
6.
《文物保护研究》2013,58(3):148-152
AbstractMineralogical changes which occur during the reaction of copper(II) chloride with carbonate in aqueous solution have been investigated, and compared with those involving copper(I) chloride, nantokite, CuCI, and copper artifacts coated with malachite, CU2CO3(OH)2 The reactions observed and the products obtained are seen to have implications with respect to the use of aqueous sodium carbonate solutions to stabilize archaeological copper objects. The frequent observation of the mineralogically rare species chalconatronite, Na2Cu(CO3)2·3H2O, on the surface of treated objects is readily explained by known reaction chemistry. Its formation can be minimized by washing the object after treatment. 相似文献
7.
《文物保护研究》2013,58(4):231-254
AbstractAnalyses of pigments from palettes used by J.M.W. Turner (active c.1792–c.1850) by means of microscopy, microchemical analysis, thin-layer chromatography, energy-dispersive X-ray analysis, X-ray diffraction and Fourier transform infrared spectroscopy are given. The occurrence of pigments in Turner's dated oil paintings and watercolours is also given, arranged by five-year periods. These findings are discussed in the context of published analyses of pigments from the first half of the nineteenth century. Turner used cobalt blue, emerald green, viridian, orange vermilion, barium chromate, chrome yellow, chrome orange and chrome scarlet within a few years of their known dates of discovery. It has become clear that Turner was using, or at least experimenting with, practically all the pigments known to be available at that time. In a few cases, in the light of these results, ideas on the availability of pigments to English artists have been revised backwards to the first known date of manufacture. Turner also possessed and used a wide range of red and yellow organic pigments, but few organic greens. The dyestuff extracted from Rubia tinctorum L. madder on an aluminiumcontaining substrate can be distinguished from the same madder on different substrates by its strong pink fluorescence in both ultraviolet and green light. The other red organic pigments (a second madder, brasilwood and cochineal dyestuffs on a range of substrates containing aluminium, copper, iron, aluminium/copper and clays) show negligible fluorescence. The red organic pigments were used in oil medium as well as watercolour, the yellows only in watercolour medium. 相似文献
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9.
Anabelle Križnar 《文物保护研究》2014,59(5):289-299
One of the most important artistic circles in the first half of the fifteenth-century in Austria was the so-called ‘Older Villach's workshop’, founded by Frederic of Villach, a painter who was considered a master of fresco technique. A technical study was made of a number of wall painting cycles by the workshop of Frederic of Villach, first, to gain a broader knowledge of the painting techniques employed, and second, to allow comparison with a further group of wall paintings in Slovenia, which are stylistically related to this workshop and have been studied previously. Of special interest were artworks attributed to Frederic's son Johannes of Ljubljana and a number of other anonymous painters that show important similarities to Frederic's works. Samples of plasters and pigments were analysed by optical microscopy, scanning electron microscopy with energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and X-ray diffraction. An important difference in the composition of plasters was discovered between the selected artistic groups. The palette used comprised predominantly earth and other mineral pigments. The construction of the paintings from incisions and preparatory drawings to the final modelling is basically similar and shows workshop connections. The principal painting technique was a fresco. The results contribute to a wider knowledge concerning the materials and techniques employed in gothic wall paintings in the Alpine region and offer new information that can be used to inform the future conservation of these selected wall paintings. 相似文献
10.
《文物保护研究》2013,58(3):204-215
AbstractThree paintings from a group of thirty-two attributed to Jackson Pollock (1912–1956) were examined at the Harvard Art Museums. Paint samples were examined using Raman spectroscopy, scanning electron microscopy–energy dispersive X-ray spectrometry (SEM-EDX), laser desorption ionization time-of-flight mass spectroscopy (LDI-MS), Fourier transform infrared spectroscopy (FTIR), pyrolysis–gas chromatography–mass spectrometry (py-GCMS) and carbon-14 (C-14) dating. Carbon-14 dating detected no 'bomb' carbon from atmospheric atomic testing. All three paintings contained pigments and media available only after Pollock's death, including PR 254, PY151, and an emulsion copolymer of n-butyl methacrylate and iso-butyl methacrylate. 相似文献
11.
《文物保护研究》2013,58(2):82-83
Abstractsystematic study of the whole thickness of the ground was carried out on about 50 paintings. The originality of the work consisted in first revealing by back -scattered scanning electron microscopy where two types of coating had been used. The components of each layer were then analyzed by X-ray diffraction and found to be principally anhydrite for the gesso grosso and gypsum for the gesso sottile. According to these results, Tuscan painters used a double white ground until the end of the fifteenth century. The use of a single layer of gypsum was widespread in other Italian schools in the fifteenth century. 相似文献
12.
《文物保护研究》2013,58(3):127-130
AbstractSamples from the external facade, internal pillars, wall and floor mosaics of the Cathedral of Salerno and mosaic samples from the Cathedral Museum were examined by X-ray diffraction, thermo-differential analysis and by thermo-gravimetric analysis. They were shown to be lime mortars containing varying amounts of an inert fraction such as dolomite, quartz, microcline, sanidine, diopside, analcime and augite. The predominant binder was calcite deriving from Ca(OH)2 The existence of relicts of Ca(OH)2 and Mg(OH)2 of low crystallinity in some samples is discussed. 相似文献
13.
Copper trihydroxychloride [Cu2Cl(OH)3] exists with four polymorphs: atacamite, paratacamite, clinoatacamite, and botallackite. They have all been used as green pigments, usually under the name atacamite. For many years, atacamite was regarded as a pigment mainly used in ancient South America, China, and Egypt. However, the last decades have shown that atacamite has been found in European medieval paintings, and quite often in Sweden. This paper gives a brief overview of the history of atacamite and its polymorphs. Green pigments from medieval murals in 56 Swedish churches were analyzed. The results show that atacamite and malachite are common, while green earth is less frequent and green vivianite rare. In particular, atacamite often occurs in medieval wall paintings on the island of Gotland in the Baltic Sea. The atacamite minerals are rare in Europe and are not found in the Swedish bedrock. Their occurrence in Swedish murals and their origin is discussed. Atacamite may be synthesized by various methods and is in fact often observed on corroded outdoor bronze statues in marine surroundings. 相似文献
14.
A technical study was conducted on a group of copper alloy artifacts excavated from the burial tumulus of Lofkënd (fourteenth–ninth century BCE) to identify the alloy compositions and methods of manufacture. The surface corrosion was also examined in order to understand the diagenetic processes affecting the preservation of the finds and their condition. Portable X-ray fluorescence spectroscopy, metallographic examination, and X-ray powder diffraction (XRD) analysis were used to characterize the alloy composition and identify the corrosion products present. XRD analysis showed the presence of brochantite (Cu4SO4(OH)6) on five of the metallic artifacts. Brochantite is not commonly reported on archaeological bronzes from terrestrial sites, but is more readily found on copper alloy objects exposed to sulfur pollutants in the air or soil. The possible conditions that could have led to the formation of this corrosion on the bronzes from Lofkënd are discussed in the context of the particular burial environment found at the tumulus. 相似文献
15.
《文物保护研究》2013,58(4):264-272
AbstractThe removal of calcareous accretions from archaeological bronzes can be a difficult step in their conservation. Chemical cleaning with chelating agents might be an alternative to mechanical methods. In this study the use of the chelating agent sodium tripolyphosphate (STPP) was examined to determine whether it is effective in discriminating between calcium carbonate and copper patina, and non-corrosive to copper alloys in the presence of air. Comparative experiments with STPP and disodium ethylenediamine-tetraacetate (Na2-EDTA) were carried out on synthetic malachite, cuprite, calcium carbonate, naturally polished malachite surfaces and sheets of bronze and brass. In addition to the properties of the chelating agent, the solubility of the salts and the pH values of the solutions are crucial factors in the removal of compounds of low solubility. The quantity of metal ions dissolved, estimated by atomic absorption spectral analysis and scanning electron microscopy, showed that the calcareous accretions could be removed satisfactorily, but STPP also dissolved constituent parts of the patina, such as malachite and cuprite, and may harm bronze or brass. Compared to Na2-EDTA, STPP is less effective in dissolving calcium carbonate. It is less harmful to the patina and base metal, but may lead to patination of the underlying metal. 相似文献
16.
A sodium copper formate, first described in 2002, can also form on copper alloys with sodium originating from soda glass hydrolysis. The frequent occurrence (50% of 250 cases of glass-induced metal corrosion) is due to the presence of formaldehyde emissions in storage and its direct reaction to formate in the alkaline surface films. The compound can be produced without the presence of acetate when chalconatronite or metal coupons immersed in soda solution are exposed to formaldehyde vapours. The crystal structure, derived from X-ray powder diffraction, yielded the sum formula Cu4Na4O(HCOO)8(OH)2·4H2O. Except for the absence of acetate in the structure, this is in good agreement with the 2002 publication. To assess which kind of combined glass/metal objects are affected, a number of large museum collections were surveyed. Sodium copper formate was detected as a corrosion product using mainly micro-Raman spectroscopy, for instance, on 18 painted Limoges enamels, eight glass vessels with metal mountings, glass beads on metal wire from 11 bridal crowns, nine Christmas tree balls with wire decoration, 40 pieces of jewellery with glass gems, three daguerreotypes, and one miniature with cover glasses. 相似文献
17.
《文物保护研究》2013,58(4):209-214
AbstractWell-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
18.
《文物保护研究》2013,58(2):112-115
AbstractThe present work demonstrates by means of two practical examples the extreme importance of examination of cross sections of metal threads to obtain an overview of their structure and of the different materials employed in their manufacture. Problems that might be caused by disturbance of surface features during polishing were prevented by covering the sample before embedding with a layer of nickel, using electroless deposition. Results from scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy (SEM-EDX) showed that, although the mean chemical composition of both metal wires is the same, their metallurgical structure is completely different: one consisting of pure silver with inclusions of copper particles and the other a silver–copper alloy. 相似文献
19.
《文物保护研究》2013,58(2):125-134
AbstractA small but significant proportion of the archaeological iron objects in the British Museum collection have been problematic in that some of them have required repeated treatment. The deterioration of iron objects during storage was studied using microscopy, Raman spectroscopy, X-ray diffraction, scanning electron microscopy/energy dispersive X-ray analysis, X-ray fluorescence spectroscopy and ion chromatography. A total of 125 iron objects, including 56 from two British Roman sites and 69 from three Anglo-Saxon sites, were studied. Both surface corrosion and corrosion layers on polished cross-sections were investigated. The study revealed that the present condition of the iron objects varies; some are in a stable condition and others have been deteriorating, with pitting and weeping present on the surface. No treatment method had stopped corrosion for every object, although the alkaline sulphite treatment seemed to be more effective than the other methods. The results also showed that chloride ions can be present at the interface of the metal and inner corrosion layers. It is recommended that iron objects which have been mechanically cleaned without desalination treatments are kept in a dry environment to prevent further deterioration. 相似文献
20.
《文物保护研究》2013,58(1):25-37
AbstractMarble specimens were impregnated with epoxy resins by first soaking the specimens in a solvent and then treating them, in steps, with increasing concentrations of the resin in the resin-solvent mixture. This resulted in impregnation to several centimeters’ depth into the specimen. Both impregnated and non-impregnated specimens were subjected to 3000 ppm SO2 atmospheres in a dynamic system. X-ray diffraction and fluorescence studies to determine the deterioration quantitatively, revealed that transformation of the outer layer of non-impregnated marble into primarily calcium sulfite stopped after a maximum of 15 mole percent conversion under normal conditions of humidity. While certain impregnated marble specimens showed significant protection from SO2 attack, other impregnated specimens revealed more reactivity than the controls. A partial explanation of this has been obtained by scanning electron microscopy which showed that the resin films on the surface were perforated. Coatings of certain acrylics provided some additional protection to impregnated specimens. 相似文献