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1.
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   

2.
《文物保护研究》2013,58(2):54-61
Abstract

Samples of pigments from excavated wall paintings of Vergina’s second tomb were analyzed by the non-destructive methods of X-ray fluorescence, X-ray diffraction and mineralogical microscopic examinations. The results showed that one type of blue pigment was used, the well-known Egyptian blue. The red pigments, except one which is haematite, are cinnabar (HgS), and the grey pigments are carbon. None of the black pigments contained manganese compounds.  相似文献   

3.
《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   

4.
《文物保护研究》2013,58(3):183-186
Abstract

A 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   

5.
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   

6.
《文物保护研究》2013,58(2):62-72
Abstract

Although smalt, a glass, might be expected to behave as a stable pigment, discolouration of smalt-containing paint layers has been observed. Early references from the literature are cited which mention the discolouration of smalt in oil media. Originally blue layers on paintings have changed into dull grey or greyish-green. Experiments suggest the following factors for this discolouration: low refractive index of the pigment compared with that of oil media; interaction of alkali content or cobalt content with oil and oleo-resinous media; the possibility of similar reactions with resin- or oil-resin varnishes in certain conditions. Discolouration may also occur if smalt is mixed with other pigments, or added as a drier or as an adulterant.

A proper understanding of the mechanism of the deterioration would require further research by more sophisticated methods.  相似文献   

7.
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   

8.
《文物保护研究》2013,58(3):181-188
Abstract

The red iron oxide pigment known as burnt yellow earth has been used as a substitute for naturally occurring red earth since earliest times. Documentary evidence indicates that this pigment was often produced by heating yellow earth for anywhere from a few minutes up to several hours at temperatures below 8000 C. When yellow earth is burnt under these conditions, its constituent goethite is transformed to red iron oxide with an anomalous diffraction pattern corresponding to a disordered haematite crystal structure. Using pigments of known origin and processing, it is shown that X-ray microdiffractometry can be used to classify very small samples of red iron oxide pigments and that, in some cases, the diffraction pattern can provide evidence to support or refute the use of burnt yellow earth.  相似文献   

9.
《文物保护研究》2013,58(4):239-258
Abstract

Study by X-ray microanalysis of 155 coloured grounds from French paintings of the seventeenth and eighteenth centuries allowed us to establish the nature of their constituents. The colour was introduced by three varieties of pigment, brown earths, ochres and iron oxides which were used in combination with calcium carbonate, lead white and minium. This confirms the recipes mentioned in the old treatises. The presence of barium sulphate, unexpected in this period, is connected with the nature of the coloured pigments and the place of execution of the works.  相似文献   

10.
Pigments on a figurative wall painting in Poudeh village, central Iran, were analysed by micro X-ray fluorescence spectrometry, micro Raman spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray spectrometry, micro Fourier transform infrared spectroscopy, X-ray diffractometry, and polarised light microscopy. Red lead, ultramarine blue, chrome yellow, brass powder, white huntite, and lammerite (Cu3(AsO4)2) were identified as red, blue, yellow, golden, white, and green pigments, respectively, while gypsum and barite were used as extender. In addition, glushinskite (MgC2O4·2H2O) was identified as a deterioration product of white huntite. Moreover, several analytical studies suggested that lammerite was a degradation product of emerald green (Cu(CH3COO)2·3Cu(AsO2)2) originally used as green pigment in the painting. The formation of lammerite is suggested to be due to the migration of arsenic throughout the paint layer. Based on the pigments identified, the wall painting is dated from the mid-nineteenth century to the mid-twentieth century.  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.
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   

13.
《文物保护研究》2013,58(3):186-203
Abstract

Safflower 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   

14.
《文物保护研究》2013,58(4):265-273
Abstract

This paper reports on the results of experiments to test for visual changes to paint systems after biocidal treatments, using a statistical binary procedure. Four biocides were selected, two of which are fungicides—a quaternary ammoniumorganotin mixture (BioMet 66®)in distilled water and an orthophenylphenol (Lysol®) in a spray— and two of which are fumigants—sulfuryl fluoride (SO2F6), a gas (Vikane®), and nitrogen gas (N2) (as an anoxant). The procedure used to assess the effect of the biocidal treatments was a random field visual scoring regimen by two paintings conservators. The tests were conducted on 30 combinations of linen, rabbitskin glue size, lead white oil ground and oil-based paints. The visual assessment procedure provided information on color change, gloss change, blanching, topography change and precipitation. The results indicated that Vikane adversely affected 10 of 11 pigment systems; Lysol adversely affected six of 11 pigment systems; BioMet 66 had a minor effect on four of 11 pigment systems; and nitrogen had no visible effect on any sample. The visual technique provided a quick and broad method for assessment of non-subtile visual changes.  相似文献   

15.
《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   

16.
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   

17.
《文物保护研究》2013,58(4):231-254
Abstract

Analyses 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   

18.
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   

19.
《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   

20.
《文物保护研究》2013,58(3):231-249
Abstract

This 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   

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