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In this work, micro-Raman spectroscopy and micro-energy-dispersive X-ray fluorescence spectroscopy (µ-EDXRF) were applied on microsamples taken from the Plaiko Zubixe footbridge (1927) located in Ondarroa (Basque Country, Spain) in order to investigate the original paint coating and make an evaluation of the conservation state before its restoration. Elemental and molecular images were acquired for the study of the compounds distribution. Some modern pigments such as phthalocyanine blue and green pigments, minium, calcium carbonate, Prussian blue, and hematite were identified. Barium sulfate and titanium dioxide were recognized as opacifier agents. Thanks to the study of the stratigraphies, it has been possible to determine the original paint layer, which includes lead white, ultramarine blue, carbon black, and barium sulfate. In addition, colorimetric analyses made it possible to know the CIELab values of the original layer in order to reproduce the original colour during the planned restoration work. The massive presence of chlorine detected by µ-EDXRF and the corrosion products of the rust layer, in particular akaganeite and hematite, highlighted the atmospheric impact in the conservation of the bridge because they were due to the effect of both marine aerosol and to the presence of acidic components in the environment coming from anthropogenic activity. This work demonstrated the usefulness of a scientific approach for the study of industrial archaeology heritage with the aim to contribute to its conservation and restoration. [ABSTRACT FROM AUTHOR]

The Historical and Cultural Heritage of Punta Begoña Galleries in Getxo (Bizkaia, North of Spain) are currently in restoration after being abandoned for years. For that reason, many graffiti, which directly affect the wall paintings, appear on most of their walls. Moreover, several graffiti overlap each other, which makes their removal more difficult. For all these reasons, the chemical characterization of these pigments is a priority to optimize the cleaning and consolidation treatments of wall paintings. That being the case, an analysis based on Raman spectroscopy and X-ray fluorescence was carried out to obtain information to help conservators remove the graffiti without damaging the mural paintings and the support. Nevertheless, the first step, using X-ray fluorescence and Raman spectroscopy, involved the need for a database to compare the results and identify the compounds. Thus, different commercial inks were elementally and molecularly characterized to complete the existing databases. After this, an analysis of the inks was carried out that noted the presence of several organic pigments, such as phthalocyanines. Inorganic pigments such as titanium oxide were identified as well. After the analysis, the selection of the best removal process could be carried out to provide the most effective treatment, avoiding the "trial-and-error" classical practice. [ABSTRACT FROM AUTHOR]

This work reports the results of an extensive study carried out on the wall paintings preserved inside the Saint Stephen's chapel in Montani (Val Venosta, Bozen, Italy), by means of μ‐Raman spectroscopy, portable X‐ray fluorescence (XRF) spectrometry, and powder X‐ray diffraction, in order to characterize materials and their alteration products that cause the blackening of paintings. In situ XRF analysis allowed identifying the areas of interest where the blackening appeared. The complementary analytical techniques allowed reconstructing a chromatic palette used by the artists that includes expensive pigments, such as lapis lazuli and cinnabar, indicating a wealthy client. Raman spectra at very low power recorded on blackened degraded samples showed the presence of a mixture of the two polymorphs of lead (IV) dioxide, plattnerite (β‐PbO2), and scrutinyte (α‐PbO2), as degradation products of lead‐based pigments. On these samples, no evidence of white lead was found, although a white lead conversion treatment had been applied on the paintings. The degradation of red lead (Pb3O4) into a mixture of plattnerite, scrutinyte, and anglesite (PbSO4) was demonstrated in some darkened samples. Furthermore, the degradation of haematite (Fe2O3) with the formation of magnetite (Fe3O4) and coquimbite (Fe2(SO4)3·9H2O) was also identified as responsible for the blackening of the paintings. The influence of original materials and environmental and anthropogenic factors such as the valley's orography and the presence of contaminating agents (SOx) is discussed to explain the decay phenomena. [ABSTRACT FROM AUTHOR]

Most of the wall paintings from Pompeii are decorated with red and yellow colors but the thermal impact of 79 AD Mount Vesuvius eruption promoted the partial transformation of some yellow-painted areas into red. The aim of this research is to develop a quantitative Raman imaging methodology to relate the transformation percentage of yellow ochre (goethite, α-FeOOH) into red color (hematite, α-Fe2O3) depending on the temperature, in order to apply it and estimate the temperature at which the pyroclastic flow impacted the walls of Pompeii. To model the thermal impact that took place in the year 79 AD, nine wall painting fragments recovered in the archeological site of Pompeii and which include yellow ochre pigment were subjected to thermal ageing experiments (exposition to temperatures from 200 to 400 °C every 25 °C). Before the experiments, elemental information of the fragments was obtained by micro-energy dispersive X-ray fluorescence (μ-ED-XRF). The fragments were characterized before and after the exposition using Raman microscopy to monitor the transformation degree from yellow to red. The quantitative Raman imaging methodology was developed and validated using synthetic pellets of goethite and hematite standards. The results showed almost no transformation (0.5% ± 0.4) at 200 °C. However, at 225 °C, some color transformation (26.9% ± 2.8) was observed. The most remarkable color change was detected at temperatures between 250 °C (transformation of 46.7% ± 1.7) and 275 °C (transformation of 101.1% ± 1.2). At this last temperature, the transformation is totally completed since from 275 to 400 °C the transformation percentage remained constant. [ABSTRACT FROM AUTHOR]

Raman microscopy is a molecular technique that is able to detect compounds that are present in the samples at minor/trace levels thanks to the precise focusing on particles of interest. The detection will also depend on the Raman scattering of the measured compound. Moreover, due to the nondestructive character of the measurements, this technique is one of the most used when samples under study belong to the arts and archaeological fields. Among the different archaeological sites in the world, Pompeii is one of the most important ancient cities. In this work, Raman microscopy—supported by X‐ray diffraction—has been used to detect traces of mineralogical phases of volcanic origin and contaminations in red and yellow ochre pigments. These samples were buried for thousands of years and recovered from the archaeological site of Pompeii in their original bowls. On the one hand, regarding the characteristic mineral phases of volcanic origin, the obtained results showed the presence of langite [Cu4 (SO4)(OH)6·2H2O], jarosite [KFe3 (SO4)2(OH)6], atacamite [Cu2Cl (OH)3], and anatase (β‐TiO2), a polymorph of titanium oxide found in igneous rocks. On the other hand, contamination compounds such as Egyptian or Pompeian blue (CaCuSi4O10) and huntite [Mg3Ca (CO3)4] were also identified. Some of the compounds identified by micro‐Raman spectroscopy could not be detected using X‐Ray diffraction and vice versa. Therefore, it was corroborated the necessity of using more than one unique technique in order to obtain a complete information about the molecular composition of the ochre pigments under study. Raman microscopy was used in order to detect contaminations and characteristic volcanic compounds.It was the first time that volcanic compounds such as langite, anatase, and atacamite were detected in Pompeian pigments.Egyptian blue and huntite were detected by Raman microscopy but not by XRD, pointing out that their concentration in the pigment composition was lower than 5%, which means that they are present due to a contamination. [ABSTRACT FROM AUTHOR]

A multianalytical methodology based on Raman spectroscopy was proposed to carry out the analysis of two wall paintings located in Saint Andrew Church (Biañez, Biscay) and Saint John the Baptist Church (Axpe, Biscay). On the one hand, Raman, assisted with energy-dispersive X-ray fluorescence and diffuse reflectance infrared portable spectrometers, was used in the in situ analysis of original support materials and pigments as well as in the identification of the degradation products. Such portable spectroscopic techniques allow identifying the areas to be sampled in order to perform deeper analyses by means of Raman chemical imaging and scanning electron microscope equipped with an energy dispersive spectrometer. Cross-sections were performed with the micro-samples taken in the areas of interest. Thereby, the colour palette, the mortar, the restoration processes and the degradation products were determined. The Raman analyses revealed that the transformation of gypsum into anhydrite in the intonaco layer was responsible for the detachment observed in the wall paintings from Axpe. Several hypotheses such as the harmful effect of previous restorations have been considered as precursor of the damage. Besides, decaying products, such as nitrates and oxalates, derived from physicochemical processes in the raw materials were also detected. Copyright © 2012 John Wiley & Sons, Ltd. [ABSTRACT FROM AUTHOR]

In this work, decorative wallpapers (19th century) from an historical palace located in Oiartzun (Basque Country, Spain) were analyzed before their restoration. Micro-energy dispersive X-ray fluorescence spectroscopy, Raman spectroscopy, and attenuated total reflectance infrared spectroscopy were used to investigate the elemental and molecular composition of pigments, the presence of binders, and the state of conservation of the paper support. The aim of the investigation was trying to understand the possible degradation pathways and identify the raw materials in order to choose the best restoration protocol according to the original aspect of wallpapers. As stated from both the elemental distribution and the identification of mineral phases by Raman spectroscopy, the most used pigment was lead chromate. It was mixed with other pigments such as ultramarine blue, zinc chromate, hematite, and atacamite among others to obtain different shades and they were applied mixed with an animal glue. Brass, identified thanks to elemental micro-EDXRF maps, was employed as a shiny decorative element. In addition, a partial degradation of cellulose was detected due to its natural ageing, the acidic nature of lignin, and to a phenomenon of humidity of the walls. Probably the deposition of black particulate matter was the cause of the darkening of the painting surfaces. [ABSTRACT FROM AUTHOR]

Pigments are one of the most important archaeological records recovered from the burial of Pompeii. Therefore, their analysis and characterization is an important task from the historical, archaeological and chemical point of view. In this work, a unique collection of various coloured raw pigments conserved in their original bowls recovered from the archaeological excavations of Pompeii was characterized. Nowadays, these pigments are stored both in the Naples National Archaeological Museum (MANN) and in the Applied Research Laboratory from the archaeological site of Pompeii (ARLP) due to its high archaeological value. For the molecular analysis, in situ micro-Raman spectroscopy was used and the elemental characterization was conducted by means of hand-held energy dispersive X-ray fluorescence (HH-ED-XRF). Mercury sulphide (HgS) and red ochre (hematite, Fe 2 O 3 ) were identified in different red pigments and yellow ochre (goethite, FeOOH) in the analyzed yellow colours. The analyzed blue pigments were Pompeian blue (CaCuSi 4 O 10 ) in all cases, green pigments were composed mainly by malachite (Cu 2 CO 3 (OH) 2 ) and the white one resulted to be dolomite CaMg(CO 3 ) 2 . Pink powders appeared to be lake pigments, using madder lake (alizarin and purpurin) as organic colorant in order to dye the inorganic mordant (local clays). In the case of blue and pink pigments Principal Component Analysis (PCA) was performed in order to see similarities/differences in the elemental composition among samples of the same colour. Groups within samples of the same colour were identified pointing out different sources of the raw material or enrichments in leachable metals present in soils during the burial. [ABSTRACT FROM AUTHOR]

This paper presents the results of a multidisciplinary research based on the use of different diagnostic techniques for the study of wall paintings that belong to the late Gothic period and are preserved in the church of Saint Stephen in Ribera de Valderejo (Álava, Basque Country). Portable Raman and X-ray fluorescence spectroscopy measurements carried out in-situ allowed to characterize the plaster composition, the colour palette used by the artists and the materials employed during the restoration works in recent times. The analyses were focused especially on some areas that appear unusually grey. Apparently, the results obtained by both techniques seem to be contradictory and it was necessary to perform a selective sampling in some areas of interest which were analyzed in the laboratory. Raman spectroscopy and scanning electron microscope, coupled with energy dispersive X spectroscopy, applied on the cross-section of micro samples, made possible to clarify some important issues, showing the inadequacy of the restoration works carried out in previous years and the presence of a potentially dangerous material too (magnesium arsenate), whose use was not documented. The results demonstrated the importance of using diagnostic tools for the identification of the materials belonging to Cultural Heritage, especially before restoration works in order to choose the most appropriate methodology and to respect the original appearance of the paintings. [ABSTRACT FROM AUTHOR]

Highlights: [•] Determination of the pigments present in a wallpaper of nineteenth century. [•] Applicability of the combination of DRIFT and FIR. [•] Validated by Raman spectroscopy and Electron Dispersive X-Ray Fluorescence (EDXRF). [ABSTRACT FROM AUTHOR]

Abstract: Several Finish wallpapers from the 18th and 19th century were analysed by using Raman spectroscopy assisted with EDXRF instrumentation, in an attempt of determine the pigments used in their manufacture process as well as of trying to date some of the samples through pigment composition. All pigments present in samples were determined and surprisingly the unusual and strange iron (III) chromate yellow pigment was found. Besides, unusual mixtures were found to obtain fashionable colours, especially in blue and green areas, where more than one blue pigments were mixed with green and yellow pigments. Blue verditer, ultramarine blue, Prussian blue, chrome yellow, calcite, lead white, red and yellow iron oxide, gypsum and carbon black were identified. The presence of the risky and poisonous emerald green must be highlighted. The results were compared with those found in other wallpapers from Spain and France. [Copyright &y& Elsevier]