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1.
PLoS One ; 19(6): e0303635, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38870129

RESUMO

Tefillin are Jewish ritual artifacts consisting of leather cases, containing inscribed slips, which are affixed with leather straps to the body of the tefillin practitioner. According to current Jewish ritual law, the tefillin cases and straps are to be colored black. The present study examines seventeen ancient tefillin cases discovered among the Dead Sea Scrolls in caves in the Judean Desert. All seventeen cases display grain surfaces with a very dark, nearly black appearance. We start with a hypothesis that the cases were intentionally colored black in antiquity using either a carbon-based or iron-gall-based paint or dye. The aim of this study is to test this hypothesis by subjecting these tefillin cases to a battery of examinations to assess the presence of carbon and iron used as pigments, and of organic materials which may have been used as binding agents in a paint. The tests deployed are: (1) macroscopic and microscopic analyses; (2) multispectral imaging using infrared wavelengths; (3) Raman spectroscopy; (4) Fourier transform infrared spectroscopy (FTIR); and (5) scanning electron microscope (SEM) and energy dispersive X-ray (EDX) spectroscopy. The results of these tests found no traces of carbon-based or iron-gall-based pigments, nor of organic compounds which may have served as binders in a paint. These results suggest that our posited hypothesis is unlikely. Instead, results of the SEM examination suggest it more likely that the black color on the surfaces of the tefillin cases is the result of natural degradation of the leather through gelatinization. The Judean Desert tefillin likely represent tefillin practices prior to when the rabbinic prescription on blackening tefillin was widely practiced. Our study suggests that the kind of non-blackened tefillin which the later rabbis rejected in their own times may well have been quite common in earlier times.


Assuntos
Análise Espectral Raman , Humanos , Espectroscopia de Infravermelho com Transformada de Fourier/métodos , Análise Espectral Raman/métodos , História Antiga , Pintura/análise , Pintura/história , Cavernas , Espectrometria por Raios X , Clima Desértico , Comportamento Ritualístico , Corantes/análise , Corantes/química
2.
Anal Methods ; 16(18): 2959-2971, 2024 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-38680024

RESUMO

Polysaccharide-based materials of plant origin are known to have been used as binding media in paint and ground layers of artifacts from ancient Egypt, including wall paintings, cartonnages and sarcophagi. The use of gums from Acacia, Astragalus and Prunus genera has been suggested in the literature on the basis of their qualitative or quantitative monosaccharide profile after complete chemical hydrolysis. The introduction of partial enzymatic digestion of the polysaccharide material, followed by analysis of the released oligosaccharides by matrix assisted laser desorption ionization-time-of-flight mass spectrometry, has proved effective in discriminating among gums from different genera, as well as among species within the Acacia genus. In this study, the previously built Acacia database was expanded, principal component analysis (PCA) was used to aid in grouping of the samples, and data interpretation was refined following a modified acacieae taxonomy. Application of the analytical strategy to investigate the paint binders in artworks from ancient Egypt allowed qualitative discrimination of gums at a species level, and provided new insights into the artists' material choices.


Assuntos
Pintura , Polissacarídeos , Análise de Componente Principal , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Pintura/análise , Pintura/história , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz/métodos , Polissacarídeos/química , Polissacarídeos/análise , Análise Multivariada , Egito , Antigo Egito , História Antiga
3.
Spectrochim Acta A Mol Biomol Spectrosc ; 279: 121414, 2022 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-35640470

RESUMO

Many issues in the conservation of paintings from the early modern period are still unresolved due to lack of information on paints from the late 19th and early 20th centuries, in particular their production, formulations, and later degradation processes. The inconsistency of the names that paint manufacturers chose for their products furthermore compounds the challenges faced by conservators and chemists wishing to study them. This paper addresses a number of these issues through investigations of commercial tube oil paints from a paint box owned by the Norwegian painter Harriet Backer (1845-1932). Samples were analyzed using a multi-instrumental approach. Micro-attenuated total reflection Fourier transform infrared spectroscopy and micro-Raman spectroscopy - supported by micro-X-ray powder diffraction - allowed the identification of binders, pigments, and extenders. The data highlight the use of materials that were new at the time and not reported in the manufacturer's catalog. Furthermore, zinc stearate has been detected for the first time. Its detection and the absence of any zinc-based pigments confirms that zinc stearate was already used as dispersing agent in paint formulations at that time.


Assuntos
Pintura , Pinturas , Pintura/história , Pinturas/história , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman/métodos , Difração de Raios X
4.
PLoS One ; 17(1): e0263189, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35081173

RESUMO

Rock art originated some 46,000 years ago and can provide unique insights into the minds of our human ancestors. However, dating of these ancient images, especially of petroglyphs, remains a challenge. In this study, we explore the potential of deriving age estimates from measurements of the areal densities of manganese (DMn) and iron (DFe) in the rock varnish on petroglyphs, based on the concept that the amount of varnish that has regrown on a petroglyph since its creation, relative to the surrounding intact varnish, is a measure of its age. We measured DMn and DFe by portable X-ray fluorescence (pXRF) on dated Late Pleistocene and Holocene rock surfaces, from which we derived accumulation rates of Mn and Fe in the rock varnish. The observed rates were comparable to our previous findings on basalt surfaces in North America. We derived age estimates for the rock art at four sites in the northern Great Basin region of North America based on DMn measurements on the petroglyphs and intact varnish. They suggest that rock art creation in this region began around the Pleistocene/Holocene transition and continued into the Historic Period, encompassing a wide range of styles and motifs. Evidence of reworking of the rock art at various times by Indigenous people speaks of the continued agency of these images through the millennia. Our results are in good agreement with chronologies based on archeological and other archaeometric techniques. While our method remains subject to significant uncertainty with regard to the absolute ages of individual images, it provides the unique opportunity to obtain age estimates for large ensembles of images without the need for destructive sampling.


Assuntos
Arqueologia/métodos , Pintura/análise , Pintura/história , Pinturas/história , Espectrometria por Raios X/métodos , Clima , História Antiga , Humanos , Ferro/análise , Manganês/análise , América do Norte , Parques Recreativos
5.
Front Neurol Neurosci ; 43: 85-92, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30336482

RESUMO

The famous poet Arthur Rimbaud (1854-1891) stopped writing poetry at 21 years and subsequently had a rather adventurous life mainly in the Arabic peninsula and Ethiopia. He died at 37 years, only a few months after the amputation of his right lower limb due to a developing tumor in the knee, which probably was an osteosarcoma in the lower third of the femur. His letters to his sister Isabelle suggest that he suffered from severe stump pain rather than phantom limb, but since he lived only shortly after surgery (he developed extensive carcinomatosis), one does not know whether a full phantom would have developed and how this would have affected his subsequent life.


Assuntos
Cotos de Amputação , Osteossarcoma/complicações , Dor/fisiopatologia , Membro Fantasma/complicações , Amputação Cirúrgica/métodos , Cotos de Amputação/fisiopatologia , História do Século XIX , Humanos , Osteossarcoma/história , Pintura/história , Membro Fantasma/história
6.
Appl Spectrosc ; 70(1): 137-46, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26767639

RESUMO

This work presents a methodology that combines spectroscopic speciation, performed through portable Raman spectroscopy, diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), and energy dispersive X-ray fluorescence spectrometry (ED-XRF) working in situ, and thermodynamic speciation to diagnose the environmental impacts, induced by past and current events, on two wall painting panels (Nos. 9103 and 9255) extracted more than 150 years ago from the walls of a Pompeian house (Marcus Lucretius House, Regio IX, Insula 3, House 5/24) and deposited in the Naples National Archaeological Museum (MANN). The results show a severe chemical attack of the acid gases that can be explained only by the action of H2S during and just after the eruption of the Vesuvius volcano, that expelled a high concentration of sulfur gases. This fact can be considered as the most important process impacting the wall painting panels deposited in the museum, while the rain-wash processes and the colonization of microorganisms have not been observed in contrast to the impacts shown by the wall paintings left outside in the archaeological site of Pompeii. Moreover, the systematic presence of lead traces and strontium in both wall paintings suggests their presence as impurities of the calcite mortars (intonacco) or calcite binder of these particular fresco Pompeian murals.


Assuntos
Arqueologia/métodos , Pintura/análise , Pintura/história , Pinturas/história , Análise Espectral/métodos , História Antiga , Itália
7.
Anal Bioanal Chem ; 408(1): 203-15, 2016 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-26472321

RESUMO

A systematic study on the influence of pigments and sample aging on casein identification was performed on 30 reconstructed paints. The protein in all the paints was extracted into solution for analysis. The amount of protein that can be retrieved for solution-based analysis in each of the reconstructed paints was studied with a well-developed NanoOrange method before and after artificial aging. The results showed that in the paints with calcium phosphate (in bone black) and copper carbonate, hydroxide, or acetate (in verdigris and azurite), the amount of protein that can be retrieved for liquid-phase analysis is much smaller than the other paints, indicating that the protein degradation was accelerated significantly in those paints. Carbon (in vine black), calcium carbonate (in natural chalk), and calcium sulfate (terra alba gypsum and ground alabaster) did not affect much the amount of protein that can be retrieved in the paints compared to non-pigmented binder, meaning that the protein degradation rate was not affected much by those pigments. Artificial aging was observed to decrease the amount of retrievable protein in all the reconstructed paints that were studied. The enzyme-linked immunosorbent assay (ELISA) method was applied to the 28 reconstructed paints (except two verdigris paints) to assess the protein identification. The ELISA responses from the different paints were compared at fixed protein concentrations. Natural chalk, bone black, raw sienna, stack lead white, and cochineal red-violet lake had the lowest ELISA signal in this study, which indicated that the binding sites (epitopes) on the target protein in these paints are likely to deteriorate more than those in the other paints. Artificial aging did not influence the ELISA response as much as the pigments when the protein concentration was kept the same for the paints that were studied.


Assuntos
Caseínas/química , Corantes/análise , Ensaio de Imunoadsorção Enzimática/métodos , Pintura/análise , Caseínas/história , Corantes/história , História Antiga , Pintura/história
8.
PLoS One ; 10(6): e0131273, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26125562

RESUMO

Gas chromatography/mass spectrometry, proteomic and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS) analyses of residue on a stone flake from a 49,000 year-old layer of Sibudu (South Africa) indicate a mixture of ochre and casein from milk, likely obtained by killing a lactating wild bovid. Ochre powder production and use are documented in Middle Stone Age South African sites but until now there has been no evidence of the use of milk as a binder. Our analyses show that this ochre-based mixture was neither a hafting adhesive nor a residue left after treating animal skins, but a liquid mixture consisting of a powdered pigment mixed with milk; in other words, a paint medium that could have been applied to a surface or to human skin. The significance of our finds also lies in the fact that it establishes the antiquity of the use of milk as a binder well before the introduction of domestic cattle in South Africa in the first millennium AD.


Assuntos
Leite/história , Pintura/história , Animais , Animais Selvagens , Arqueologia , Bovinos , Feminino , Cromatografia Gasosa-Espectrometria de Massas , História Antiga , Humanos , Leite/química , Pintura/análise , Proteômica , África do Sul , Espectrometria por Raios X
9.
Artigo em Inglês | MEDLINE | ID: mdl-25965511

RESUMO

Sherds representative of the three Portuguese faience production centers of the 17th century - Lisbon, Coimbra and Vila Nova were studied with the use of mostly non-invasive spectroscopies, namely: ground state diffuse reflectance absorption (GSDR), micro-Raman, Fourier-transform infrared (FT-IR) and proton induced X-ray (PIXE) or X-ray fluorescence emission (XRF). X-ray diffraction (XRD) experiments were also performed. The obtained results evidence a clear similarity in the pastes of the pottery produced Vila Nova and some of the ceramic pastes from Lisbon, in accordance with documental sources that described the use of Lisbon clays by Vila Nova potters, at least since mid 17th century. Quartz and Gehlenite are the main components of the Lisbon's pastes, but differences between the ceramic pastes were detected pointing out to the use of several clay sources. The spectroscopic trend exhibited Coimbra's pottery is remarkably different, Quartz and Diopside being the major components of these pastes, enabling one to well define a pattern for these ceramic bodies. The blue pigment from the Lisbon samples is a cobalt oxide that exists in the silicate glassy matrix, which enables the formation of detectable cobalt silicate microcrystals in most productions of the second half of the 17th century. No micro-Raman cobalt blue signature could be detected in the Vila Nova and Coimbra blue glazes. This is in accordance with the lower kiln temperatures in these two production centers and with Co(2+) ions dispersed in the silicate matrix. In all cases the white glaze is obtained with the use of tin oxide. Hausmannite was detected as the manganese oxide mineral used to produce the purple glaze (wine color "vinoso") in Lisbon.


Assuntos
Cerâmica/química , Cerâmica/história , Estanho/análise , Corantes/análise , Corantes/história , História do Século XVII , Pintura/análise , Pintura/história , Portugal , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Estanho/história , Difração de Raios X
10.
New Solut ; 25(2): 172-88, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25910492

RESUMO

This paper examines the use of lawsuits against three industries that were eventually found to be selling products damaging to human heath and the environment: lead paint, asbestos, and fossil fuels. These industries are similar in that some companies tried to hide or distort information showing their products were harmful. Common law claims were eventually filed to hold the corporations accountable and compensate the injured. This paper considers the important role the lawsuits played in helping establish some accountability for the industries while also noting the limitations of the lawsuits. It will be argued that the lawsuits helped create pressure for government regulation of the industries' products but were less successful at securing compensation for the injured. Thus, the common law claims strengthened and supported administrative regulation and the adoption of industry alternatives more than they provided a means of legal redress.


Assuntos
Asbestose/prevenção & controle , Combustíveis Fósseis/efeitos adversos , Aquecimento Global/legislação & jurisprudência , Intoxicação por Chumbo/prevenção & controle , Pintura/normas , Responsabilidade Social , Amianto/história , Amianto/intoxicação , Asbestose/etiologia , Asbestose/história , Qualidade de Produtos para o Consumidor/legislação & jurisprudência , Exposição Ambiental/efeitos adversos , Exposição Ambiental/legislação & jurisprudência , Exposição Ambiental/prevenção & controle , Combustíveis Fósseis/história , Aquecimento Global/história , Aquecimento Global/prevenção & controle , Regulamentação Governamental , História do Século XX , História do Século XXI , Humanos , Indústrias/história , Indústrias/legislação & jurisprudência , Indústrias/normas , Conhecimento , Intoxicação por Chumbo/etiologia , Intoxicação por Chumbo/história , Fibras Minerais/efeitos adversos , Fibras Minerais/história , Pintura/história , Pintura/intoxicação , Vigilância de Produtos Comercializados , Má Conduta Científica/história , Má Conduta Científica/legislação & jurisprudência , Estados Unidos , Indenização aos Trabalhadores/história , Indenização aos Trabalhadores/legislação & jurisprudência
12.
Spectrochim Acta A Mol Biomol Spectrosc ; 140: 101-10, 2015 Apr 05.
Artigo em Inglês | MEDLINE | ID: mdl-25589392

RESUMO

Temperature-related degradation of pure synthetic as well as partly oxidised natural vivianite has been studied by high-temperature X-ray diffraction (HT-XRD) covering the whole extent of the temperature-related stability of its structure. While temperatures around 70°C are already damaging to vivianite, exposition to 160°C results in complete amorphisation of both the vivianite and its oxidation products. As indicated by Mössbauer spectroscopy, temperature-induced oxidation of vivianite starts at 90°C. To study the occurring structural as well as accompanying colour changes in more detail, model vivianite paint layer samples with different historic binders were prepared and subjected to increased temperatures. Exposition to 80°C caused pronounced colour changes of all the samples: ground natural blue vivianite became grey--a colour change which has been described in actual works of art. Regarding the binders, the oil seemed to facilitate the transfer of heat to vivianite's grains. To simulate conditions of conservation treatment under which the painting is exposed to increased temperatures, oil-on-canvas mock-ups with vivianite were prepared and relined in a traditional way using iron. The treatment affected preferentially larger grains of vivianite; the micro-samples documented their change to grey, and their Raman spectra showed the change from vivianite to metavivianite.


Assuntos
Corantes/análise , Compostos Ferrosos/análise , Pintura/análise , Pinturas , Fosfatos/análise , História do Século XVI , História do Século XVII , Temperatura Alta , Oxirredução , Pintura/história , Pinturas/história , Espectroscopia de Mossbauer , Análise Espectral Raman , Difração de Raios X
13.
Spectrochim Acta A Mol Biomol Spectrosc ; 136 Pt B: 594-600, 2015 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-25448959

RESUMO

Samples were obtained from two world-famous 17th century panel paintings of the Gdansk school of panting: 'Seven Acts of Charity' (1607, in St. Mary's Church in Gdansk, Poland) by Anton Möller and 'Angelic Concert' (1611, in Diocesan Museum in Pelplin, Poland) by Hermann Han. Micro-Raman spectroscopy (MRS), optical microscopy (OM), and X-ray fluorescence (XRF) spectroscopy studies of the samples were performed to characterize the pigments present in the individual painting layers (a rich palette of white, black, blue, red, and yellow pigments) and the pictorial techniques used by the artists.


Assuntos
Corantes/análise , Pintura/análise , Pinturas/história , Corantes/história , História do Século XVII , Microscopia , Pintura/história , Polônia , Espectrometria por Raios X , Análise Espectral Raman
14.
Spectrochim Acta A Mol Biomol Spectrosc ; 136 Pt B: 793-801, 2015 Feb 05.
Artigo em Inglês | MEDLINE | ID: mdl-25448977

RESUMO

The Raman and complementary spectroscopic analyses were performed using the exceptional possibility of research on the XIX c. original paint materials of the artist palette of J. Matejko stored in the National Museum in Cracow. The yellow and ochre-based paints characteristic for Matejko's workshop and selected from the ensemble of 273 labelled tubes (brand of R. Ainé/Paris) supplied during the period of 1880-1893 were investigated. Highly specific Raman spectra were obtained for paints containing mixtures of the Zn- and Sn-modified Pb-Sb pigment, and also for the ochre-based ones. A clear pigment discrimination of the mixture of cadmium yellow (CdS), cinnabar (HgS) and lead white (2PbCO3⋅Pb(OH)2) was possible by means of Raman data collected under different excitations at 514 nm and 785 nm. It was shown that the Raman spectra complemented by the XRF, SEM-EDX and in some cases also by the LIPS and FTIR data ensure reliable pigment identification in multi-component paints containing secondary species and impurities. The reported spectral signatures will be used for non-destructive investigation of the collection of about 300 oil paintings of J. Matejko. In view of the comparative research on polish painting which point out that richness of modified Naples yellows clearly distinguish Matejko's artworks from other ones painted in the period of 1850-1883, the Raman data of these paints can provide support in the authentication studies.


Assuntos
Corantes/análise , Pintura/análise , Pinturas/história , Análise Espectral Raman , Corantes/química , História do Século XIX , Pintura/história , Análise Espectral Raman/métodos
15.
Artigo em Inglês | MEDLINE | ID: mdl-25194320

RESUMO

Raman spectroscopic analysis of the pigments on an Italian painting described as a "Full Length Portrait of a Gentleman", known also as the "Malatesta", and attributed to the Renaissance period has established that these are consistent with the historical research provenance undertaken earlier. Evidence is found for the early 19th Century addition of chrome yellow to highlighted yellow ochre areas in comparison with a similar painting executed in 1801 by Sir Thomas Lawrence of John Kemble in the role of Hamlet, Prince of Denmark. The Raman data are novel in that no analytical studies have previously been made on this painting and reinforces the procedure whereby scientific analyses are accompanied by parallel historical research.


Assuntos
Corantes/análise , Pintura/análise , Pinturas/história , Análise Espectral Raman , Corantes/história , Dinamarca , História do Século XV , História do Século XIX , História Medieval , Pintura/história , Análise Espectral Raman/métodos
16.
Spectrochim Acta A Mol Biomol Spectrosc ; 131: 373-83, 2014 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-24835941

RESUMO

Samples containing red pigment have been collected from two different archaeological sites dating to the Neolithic (Çatalhöyük in Turkey and Sheikh-e Abad in Iran) and have been analysed by a range of techniques. Sub-samples were examined by IR spectroscopy and X-ray diffraction, whilst thin sections were studied using optical polarising microscopy, synchrotron based IR microscopy and environmental scanning electron microscopy with energy dispersive X-ray analysis. Thin layers of red paint in a wall painting from Çatalhöyük were found to contain ochre (hematite and clay) as well as an unexpected component, grains of red and colourless obsidian, which have not been identified in any previous studies of the wall paintings at Çatalhöyük. These small grains of obsidian may have improved the reflective properties of the paint and made the artwork more vivid in the darkness of the buildings. Analysis of a roughly shaped ball of red sediment found on a possible working surface at Sheikh-e Abad revealed that the cause of the red colouring was the mineral hematite, which was probably from a source of terra rossa sediment in the local area. The results of this work suggest it is unlikely that this had been altered by the Neolithic people through mixing with other minerals.


Assuntos
Corantes/análise , Pintura/análise , Pinturas/história , Silicatos de Alumínio/análise , Arqueologia , Argila , Corantes/história , Compostos Férricos/análise , História Antiga , Irã (Geográfico) , Microscopia de Polarização , Pintura/história , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Síncrotrons , Turquia , Difração de Raios X
17.
Appl Spectrosc ; 68(4): 434-43, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24694700

RESUMO

In this work, microspectrofluorimetry was for the first time applied to the identification of the red organic lakes that are characteristic of the lavish illuminations found in 15(th) century books of hours. Microspectrofluorimetry identified those red paints, ranging from opaque pink to dark red glazes, as brazilwood lakes. An unequivocal characterization was achieved by comparison with reference paints produced following recipes from the medieval treatise The Book on How to Make Colours, and was further confirmed by fiber optic reflectance spectroscopy (FORS). For these treasured cultural objects, microspectrofluorimetry and FORS proved to be the only techniques that could identify, in situ or in microsamples, the chromophore responsible for the pinkish hues: a brazilein-Al(3+) complex. Additionally, a multi-analytical approach provided a full characterization of the color paints, including pigments, additives, and binders. Microspectroscopic techniques, based on infrared and X-ray radiation, enabled us to disclose the full palette of these medieval manuscripts, including the elusive greens, for which, besides malachite, basic copper sulfates were found; Raman microscopy suggested a mixture of brochantite and langite. Infrared analysis proved invaluable for a full characterization of the additives that were applied as fillers or whites (chalk, gypsum, and white lead) as well as the proteinaceous and polysaccharide binders that were found pure or in mixture.


Assuntos
Livros/história , Pintura/análise , Pintura/história , Análise Espectral/métodos , Corantes/química , História do Século XV , Pigmentos Biológicos/química , Portugal
18.
Spectrochim Acta A Mol Biomol Spectrosc ; 124: 638-45, 2014 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-24513711

RESUMO

Painted metal knight shields of the Order of the Elephant produced during the last part of the 20th century are characterized by a striking variety in their conservation state. Three different coat systems were identified and investigated by Fourier transform infrared microscopy (µ-FTIR), micro-Raman spectroscopy (MRS), scanning electron microscopy-Energy dispersive X-ray spectroscopy (SEM-EDX) and Thermally assisted hydrolysis and methylation-gas chromatography-mass Spectrometry (THM-GC-MS). Chalking of the white paint layer on the first group of knight shields displayed in the window niches was found to be related to the use of titanium white of the anatase type. A pristine condition of the second group could be attributed to priming of the lead rich metal support with a zinc potassium chromate based primer and the use of mainly stable white pigments in the top coat. Severe delamination of the paint layer of the third group was caused by the formation of lead corrosion products between the paint layer and the metal support. The results are discussed in relation to the climatic conditions as well as the historical context of contemporary paint production and availability in Denmark.


Assuntos
Metais/análise , Pintura/análise , Equipamentos de Proteção , Titânio/química , Cromatografia Gasosa-Espectrometria de Massas , História do Século XX , Metilação , Pintura/história , Espectrometria por Raios X , Espectroscopia de Infravermelho com Transformada de Fourier , Análise Espectral Raman , Temperatura
19.
Spectrochim Acta A Mol Biomol Spectrosc ; 124: 308-14, 2014 Apr 24.
Artigo em Inglês | MEDLINE | ID: mdl-24503152

RESUMO

In this work the determination of the pigments present in a decorative wallpaper of the middle nineteenth century from the Santa Isabel factory (Vitoria-Gasteiz, Basque Country, Spain) has been performed by a combination of mid-Diffuse Reflectance Infrared Spectroscopy (DRIFT) and Far Infrared Spectroscopy (FIR) in transmission mode. The DRIFT is a powerful infrared technique that is not widely used in the analyses of artworks in spite of being especially adequate for powdered samples. In this mode, sample pretreatment is not required and the obtained spectra are easier to solve than those obtained in transmittance mode. Those pigments which are not active in the mid-infrared region may be determined easily by FIR. In the last decade, in the field of painted materials very few studies performed by far infrared spectroscopy and mid infrared spectroscopy in diffuse reflectance mode can be found. In most of them the researchers have used one of these techniques, but in no case the combination of both. As we demonstrate in this work, combining these two techniques a complete characterization of the wallpaper can be carried out. Small samples were collected from the wallpaper for the analysis of the rose, brown, yellow and blue colours. In this way, minium (Pb3O4), calcite (CaCO3), barium sulphate (BaSO4), prussian blue (Fe7C18N18), iron oxide yellow (α-FeOOH), vermillion (HgS) and carbon black pigment from organic origen were detected. Finally, the validation was carried out by XRF and Raman spectroscopy getting the same results as with the combination of diffuse reflectance infrared spectroscopy and far infrared spectroscopy.


Assuntos
Pintura/análise , Pintura/história , Espectrofotometria Infravermelho/métodos , Cor , História do Século XIX , Reprodutibilidade dos Testes , Espectrometria por Raios X , Análise Espectral Raman
20.
Spectrochim Acta A Mol Biomol Spectrosc ; 118: 598-602, 2014 Jan 24.
Artigo em Inglês | MEDLINE | ID: mdl-24095770

RESUMO

An opportunity was afforded to analyse pigment specimens from an unrestored oil painting in the style of the English School of the mid-18th Century prior to conservation being undertaken. Raman spectroscopy was adopted to characterise the pigments and indicated the presence of a novel red pigment which was assigned to the complex chromium mineral, hemihedrite, in addition to other interesting materials found in combination. This is the first recorded identification of hemihedrite spectral signals in an art context in a range of mineral pigments that are otherwise typical of this period and some hypotheses are presented to explain its presence based on its occurrence with associated mineral pigments. It is suggested that the presence of powdered glass identified in certain areas of the painting enhanced the reflectivity of the pigment matrix.


Assuntos
Corantes/análise , Pintura/análise , Pintura/história , Pinturas/história , Análise Espectral Raman/métodos , Cromo/análise , Cromo/história , Corantes/história , Inglaterra , História do Século XVIII , Minerais/análise , Minerais/história
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