Study of two large-dimension Murillo's paintings by means of macro X-ray fluorescence imaging,point X-ray fluorescence analysis,and stratigraphic studies

During the recent restoration of two large-dimension paintings by Murillo, entitled “Miracle of the loaves and fishes” and “Moses and the water from the rock of Horeb,” several studies about the materials employed for their execution were carried out. Macro X-ray fluorescence scanning technique was performed on both works complemented by point X-ray fluorescence and stratigraphic analyses, in order to characterize the different components of the paintings (i.e., ground layer, pigments, and binders). The results allowed us to better elucidate Murillo painting technique and his creative process. Ground layer was prepared in the usual fashion of the artist, using earths, calcium carbonate, iron oxide pigments, and white lead. The polichromy is composed of lead white mixed with various pigments, depending on the colour tone to be obtained in the pictorial composition: Red and yellow ochres, vermilion, azurite, smalt, and lead-tin yellow were the main pigments identified during our study. Finally, the presence of previous conservation treatments was evidenced by detecting pigments (zinc white, Prussian blue, etc.) not coeval with the artist palette.     

Pigment study by Raman microscopy of 23 paintings by the Portuguese artist Henrique Pousão (1859–1884)

Twenty‐three paintings by Henrique Pousão—a 19th century Portuguese painter—belonging to the collection of Museu Nacional Soares dos Reis, Porto, Portugal, were analysed by Raman microscopy. The fine focus of a 100× objective allowed the visualisation and individual identification of small grains. As a result, thirty‐seven compounds, namely, anatase, barium white, basic lead sulfate, brochantite, cadmium red, cadmium yellow, calcium carbonate, carbon‐based black, celadonite, chrome green, chrome orange, chrome yellow, cobalt blue, cochineal lake, copper sulfide, emerald green, iron(III) oxyhydroxide, iron(III) oxide, kaolinite, lead antimonate yellow, lead carbonate, lead white, lead sulfate, madder lake, malachite, Prussian blue, quartz, realgar/pararealgar, red lead, rutile, Scheele's green, strontium yellow, ultramarine blue, vermilion, viridian, zinc white and zinc yellow, were identified. Not all these compounds are pigments; some are extenders, others trace components and others probably products of reactions between pigments. Special attention was given to the Raman characterisation of celadonite, chrome orange, basic lead sulfate and lead antimonate yellow. Complementary techniques were used to confirm the identities of certain pigments and to characterise reference samples. Pousão, whose work has not previously been studied spectroscopically, was found to have used a remarkably wide range of pigments over his painting periods, without showing significant preference for any particular set of pigments. Copyright © 2007 John Wiley & Sons, Ltd.     

Analysis of paintings from the nineteenth century Brazilian painter Rodolfo Amoedo using EDXRF portable system

The pigments used in four of the most representative paintings of the Brazilian artist Rodolfo Amoedo were characterized by means of the EDXRF technique. The analyzed paintings were ‘The Last Tamoyo’ (1883), ‘Study of a Woman’ (1884), ‘Bust of Mrs. Amoedo’ (1892) and ‘Bad News’ (1895). EDXRF measurements were carried out with a portable system developed by the Nuclear Instrumentation Laboratory, consisting of an x‐ray tube Oxford TF3005 with a W anode, operating at 25 kV and 100 µA, and a Si‐PIN XR‐100CR detector from Amptek. Several spectra were obtained in each color and distinct hue of the paint layer, with an acquisition time of 300 s and a beam collimation of 2 mm. Some pigments used by the artist were zinc white, lead white, ochre, umber, vermilion, Prussian blue, cobalt blue, cadmium yellow, black iron oxide and manganese violet. In the painting ‘The Last Tamoyo’, titanium white was identified in some alteration areas, which were restored during the twentieth century. These results—together with computed radiography analyses—will be used to create a database about the nineteenth‐century collection of the National Museum of Fine Arts, in order to assist restorers, conservators, art students and researchers in the field of archeometry. Copyright © 2009 John Wiley & Sons, Ltd.     

Micro‐Raman spectroscopy analysis of 16th century Portuguese Ferreirim Masters oil paintings

In the present work a set of eight altarpieces of the 16th century (1532–1534), attributed to the Ferreirim Masters (Gregório Lopes, Garcia Fernandes and Cristóvão de Figueiredo), from the Santo António de Ferreirim Monastery (North of Portugal), were analysed by micro‐Raman spectroscopy. For this purpose some samples were taken from the paintings to characterise its artist's ‘school’. It was found that the preparation was made with chalk and gypsum and the palette composed mainly of lamp black, azurite, lead white (mixed with other pigments), lead–tin yellow type I, goethite (the main constituent of yellow ochre), red lead (as under painting), haematite (the main constituent of red ochre) and vermilion. Indigo was detected in one sample. Some derivatives and degradation products were found mainly in the panels subjected to high temperatures during a fire occurred in 1954: a degradation product from massicot or red lead, lead carbonate (dehydrated derivative of lead white), bassanite and anhydrite (hemi‐ and dehydrated forms of gypsum). These results are compared with those of previous total reflection X‐ray fluorescence spectroscopy (TXRF) analyses. Copyright © 2009 John Wiley & Sons, Ltd.     

Synthetic organic pigments in contemporary Balinese painting: a Raman microscopy study

The colour palette from two 20th century and one 21st century Indonesian paintings from the island of Bali was determined by Raman microscopy. There is very little information concerning the artistic techniques from this region of the world and the influences in materials introduced by western artists. The most interesting finding of our study was the increasing substitution of natural pigments by modern synthetic organic pigments. The findings were also compared with samples of representative pigments commonly used by Bali artists, donated by a renowned Balinese painter. Raman microscopy, combined with Fourier transform infrared spectroscopy, high‐performance liquid chromatography and μ‐EDXRF, was able to separate the different components on several colours, and to identify both synthetic organic pigments and inorganic components. Three azo pigments from the diarylide subclass, PY 83, PY 55 and PO 16, were identified on the yellow, brown, red and orange colours. A copper phthalocyanine blue PB 15:x and a basic dye BB 26 were responsible for the blue colours, the former admixed with ultramarine blue. Goethite was sometimes introduced to create the green colour. Two other basic dyes, BY2 and PG 4, were the main chromophores of the yellow and green samples of local pigments. The inorganic pigments comprised bone white, bone black, carbon‐based black pigment, haematite, goethite, vermilion, ultramarine blue and anatase. Finally, the ground layer of all the paintings was identified as rice starch, with a double function of a white pigment. Copyright © 2012 John Wiley & Sons, Ltd.     

Pigment analysis of Portuguese portrait miniatures of 17th and 18th centuries by Raman Microscopy and SEM‐EDS

Seventeen Portuguese miniature portraits on copper support from the Évora Museum collection (Portugal) were analyzed in situ and nondestructively by Raman microscopy (RM), SEM‐EDS, and stereomicroscopy. This work constitutes a great breakthrough in the study of miniature paintings from the 17^th and 18^th centuries, since the chemical information known about this unique kind of paintings are still scarce, and in particular, this exclusive collection was never been subjected to any physicochemical study. In this work, each portrait was examined in detail in order to characterize the pigments palette used by the miniaturists. The μ‐Raman analysis, in particular, guaranteed an exceptional visualization and good individual identification of small grains of pigments and other constituents of the pictorial layer. Using this technique, 19 compounds were identified, including bluish black covellite, a pigment rarely found in oil paintings. SEM‐EDS was used as an important complementary technique to confirm the chemical nature of some pigments and to identify shell gold (gold dust) in some portraits. Overall, the pigments identified in this large set of old paintings are broadly consistent with those mentioned in the painting treatises of that time or reported in other more modern bibliographic sources. Copyright © 2014 John Wiley & Sons, Ltd.     

Application of field portable EDXRF spectrometry to analysis of pigments of Levantine rock art

The results of the analyses of elemental composition of red and black pigments of Levantine rock art from La Saltadora rock shelters (Valltorta gorge, Castellón, Spain) are presented in this paper. Nondestructive analyses were carried out using a portable energy dispersive X‐ray fluorescence (EDXRF) spectrometer developed for in situ analysis. The results revealed the strong presence of calcium in all the analyzed locations due to the contribution of the underlying calcareous bedrock and the overlying crust. Iron is the main element detected in red pigments and manganese in black pigments. Iron and calcium ratios have been found indicative of the degree of preservation of the pictorial layer. Trace elements detected in the pigment composition confirm the use of different raw materials. Therefore, this work illustrates the potential of the portable EDXRF spectrometers for in situ analysis of rock art paintings. Copyright © 2010 John Wiley & Sons, Ltd.     

A study on red lead degradation in a medieval manuscript Lorvão Apocalypse (1189)

The mechanisms of red lead degradation were studied in a medieval Portuguese codex, Lorvão Apocalypse (1189), by Raman microscopy (µ‐Raman) and micro‐X‐ray diffraction (µ‐XRD). The range of pigments found for the illuminations is mainly limited to vermilion, orpiment and red lead. Micro‐Fourier transform infrared spectroscopy (µ‐FTIR) determined that the pigments were applied in a proteinaceous binding medium. In the red and orange colours, arsenic (As) was determined, by micro‐energy dispersive X‐ray fluorescence (µ‐EDXRF), to be ranging 1–4% (wt %). For those colours, lead white and calcium carbonate were found as fillers whereas orpiment was applied as a pure pigment. Raman microscopy identified, unequivocally, the degradation product of red lead as galena [lead (II) sulphide, PbS]. To determine the main factors affecting red lead degradation, a set of accelerating ageing experiments was designed to assess the influence of extenders and of the two other pigments, vermilion and orpiment. The experiments were followed by µ‐Raman, µ‐EDXRF and XRD. Raman microscopy results for the simulation of degradation of red lead, in the presence of orpiment, are in agreement to what was found in the Lorvão Apocalypse, galena being the main degradation product; also in common is a Raman band at ca. 810 cm⁻¹, which was attributed to a lead arsenate compound. It was concluded that in Lorvão Apocalypse, the degradation of red lead was a result of its reaction with orpiment. Copyright © 2009 John Wiley & Sons, Ltd.     

In situ Raman microscopy applied to large Central Asian paintings

Procedures and versatile Raman instruments are described for the non‐destructive in situ analysis of pigments in large paintings. A commercial Raman microscope is mounted on a gantry for scanning paintings with dimensions exceeding 1 m². Design principles and the physical implementation of the set‐up are outlined. Advantages/disadvantages and performance of the gantry‐based instrument are compared with those of a mobile Raman probe, attached to the same Raman microscope. The two set‐ups are applied to Central Asian thangka paintings. The utility of the gantry‐mounted Raman microscope is demonstrated on a 19th century Buddhist painting from Buriatia, South Siberia. Surprisingly, three arsenic‐based pigments, i.e. orpiment, realgar, and pararealgar, are found all in the same painting. Pararealgar is used for painting the numerous yellow areas. Realgar is admixed with red lead for adjusting its orange tint. Finally, orpiment is blended with Prussian blue for producing green. Traditional malachite is used in addition as a non‐adulterated green pigment. The mobile Raman probe was employed for examining a Tibetan painting of the 18th century from Derge monastery in the Kham area of Sichuan. The highly unique painting could be dated well and its origin accurately located. In fact, the painter's workshop, where the thangka has been executed, is shown in great detail on the painting itself. The painter's palette of this thangka matches the canonical set of pigments used in Tibet for more than 10 centuries. Copyright © 2009 John Wiley & Sons, Ltd.     

Giotto in the Chapel of the Scrovegni: EDXRF analysis of the golden haloes with portable equipment

Energy‐dispersive x‐ray fluorescence (EDXRF) analysis is particularly suited to analyse paintings, because it does not significantly damage the sample and allows the measurement of several elements in a single measurement. The use of portable equipment allows a completely non‐destructive analysis, although the interpretation of the measured spectra requires a more accurate approach. EDXRF analysis of paintings generally gives the following information: identification of the elements, and therefore pigments, employed by the artist; possible presence of elements on the surface (sulphur, chlorine) due to pollution effects; identification of previous restoration areas, through the presence of ‘modern’ elements, such as titanium, zinc, cadmium and others. Recently, the famous Chapel of the Scrovegni, painted by Giotto in Padua in 1303–05, was analysed in detail to obtain the above information and, more specifically, to analyse the golden haloes. In this paper the measurement of sulphur on the surface of the frescoes is described, together with the composition of the golden haloes. Copyright © 2004 John Wiley & Sons, Ltd.     

An authentication case study: Antonio Palomino versus Vicente Guillo paintings in the vaulted ceiling of the Sant Joan del Mercat church (Valencia,Spain)

In 1695, the Valencian artist Vicente Guillo was engaged in painting the vault of the Sant Joan del Mercat church in Valencia, Spain. After preliminary work was carried out, his contract was cancelled. In 1697, Antonio Palomino, renowned for the publication of his technical treatise entitled El Museo Pictorio y Escala Optica, was finally selected as the painter in charge of decorating the vaulted ceiling of Sant Joan del Mercat. This paper reports an analytical study focused on the characterisation and discrimination of the palette and painting procedures used by Palomino and Guillo in the frescoes of Sant Joan del Mercat. For this purpose, Raman spectroscopy combined with light microscopy, scanning electron microscopy–X‐ray microanalysis, voltammetry of microparticles, X‐ray diffraction, Fourier transform infrared spectroscopy and gas chromatography–mass spectrometry has been employed. The use of gypsum as stucco material for the ground layers contrasts with the recommendations made by Palomino in his treatise about the convenience of using slaked lime‐sand mortars according to traditional fresco recipes. Although lead‐based pigments were not traditionally recommended for frescoes because of their empirically known alterations when subjected to strong alkaline fresco medium, both Guillo and Palomino used them. Palomino, probably supported by his personal experience as a painter, recommended and used Naples yellow, which has been found in a good state of preservation. In contrast, white lead areas found on Guillo's paintings have transformed into lead oxides. Other pigments found in the vaulted ceiling such as smalt, goethite, haematite, azurite and malachite have also undergone substantial changes because of the extreme temperature conditions to which they were subjected in the church. Copyright © 2012 John Wiley & Sons, Ltd.     

Raman spectroscopic study of medieval Indian art of 17th century

We report the first Raman spectroscopic investigations of medieval Indian art of 17th century. Three miniature paintings, belonging to Mogul and Rajput schools from the collections of the Madras Museum, were investigated by micro‐Raman spectroscopy using different excitation wavelengths. Many areas in the paintings exhibited rich spectra containing several intense Raman bands. The Raman bands were assigned on the basis of the reported reference spectra of the pigments. Evidences for the presence of massicot, red‐lead, lead‐white, vermilion, litharge, Indian yellow and anatase are found. In addition, tentative assignments of some of the Raman bands to atacamite and orpiment are also made. The present studies suggest that several mineral‐based unique pigments were popular among the Indian artists of this period. Copyright © 2010 John Wiley & Sons, Ltd.     

Portable XRF study of pigments applied in Juan Hispalense’s 15th century panel painting

Several medieval paintings and polychrome sculptures have been analysed in the frame of a collaboration between the Fine Arts Museum of Seville and the National Centre of Accelerators, dedicated to a non‐destructive study of artworks that belong to the wide museum’s collection. Among the oldest artworks in the collection is the panel painting Archangel St. Michael attributed to Juan Hispalense, one of the first painters in the 15th‐century Seville known by name. The panel was analysed by a portable X‐ray fluorescence (XRF) to get more information about the pigments applied and to identify possible later interventions. The results showed that the pigments were those commonly used in that period. Lead white was found in the preparation of the painting and in colour layers. For yellow colour, yellow ochre was used, while for the red one, the painter usually mixed red earth and vermillion. Blue pigment is azurite, while the copper‐based green one could not be determined more specifically by XRF. Brown colour is made with yellow ochre and organic black or, in some cases, umbra. Black pigment is probably bone or ivory black. Many decorative parts of the panel are gilded, which were confirmed by Au peaks. Later interventions were carried out on the base of Ti–Zn white mixed with earth pigments, while for green areas such as Archangel's wings also chrome green was applied. The research is part of a larger study which is still going on, whose aim is to gain more knowledge about the 15th‐ and 16th‐century Spanish painting and polychromy. Copyright © 2011 John Wiley & Sons, Ltd.     

Micro‐Raman and stratigraphic studies of the paintings on the ‘Cembalo’ model musical instrument (A.D. 1650) and laser‐induced degradation of the detected pigments

Micro‐fragments of the painted part of the ‘Cembalo’ model by Michele Todini (1625–1689) are investigated. The technique used for painting the terracotta base was studied via the stratigraphic analyses. No background layer of inorganic materials, e.g. gypsum, was found. To prevent absorption effects due to the terracotta porosity, a very thin layer of proteinaceous material was probably used. The micro‐Raman analyses have revealed the use of pigments currently used in the post‐Renaissance period (lead white, indigo, yellow of iron hydroxide, gypsum, hematite and carbon black) mixed with a pigment, the Prussian blue, discovered in A.D . 1704. This raises the authenticity problem of the work of art, a problem analysed and discussed in presenting the history of the work of art, and after the pigment study. The presence of degraded lead white is recognized via the laser‐induced degradation of the irradiated material. The possibility of a restoring action of the painted parts, as opposite to the non‐originality of the work, is considered and discussed. Since most part of the investigated pigments shows laser‐induced effects, a careful study of this phenomenon is performed by using the modern counterparts of the ancient pigments. For different laser powers, the temperatures of the investigated zones have been obtained via the detailed balance principle and connected to the laser‐induced degradation effects. Copyright © 2007 John Wiley & Sons, Ltd.     

Re-interpretation of the Old Masters' practices through optical and rheological investigation: The presence of calcite

Lead white, composed of a mixture of cerussite and hydrocerussite (respectively PbCO₃ and Pb₃(CO₃)₂(OH)₂), is often associated in paintings with other white pigments, especially calcite. By combining in-situ analyses with paint reconstructions, we attempt to get a better understanding of the role of this addition of calcite and to investigate how artists may have used it to modify the properties of their paints. Lead-based white pigments of a Dutch 17th-century nuancier have been analysed as well as historical paintings. Two examples are given: one from a painting by Roger van der Weyden, in the 15th century, and one by Nicolas Poussin, in the 17th century, from specific zones that indicate the addition of calcite. The presence of calcite and pigments enhances both the optical and the rheological properties. Visible reflectance spectroscopy was carried out on pure paints as well as mixtures and indicated an increase in the transparency of the paint mixture in comparison to pure lead white. Rheological measurements also indicated an increase in the elastic and viscous moduli, as well as of the yield stress again in comparison to pure lead white. Calcite could thus have been used to assist in the creation of impasto effects in lead white paints.     

Degradation of synthetic restoration materials in heterogenous systems

By the method of the optical spectrsocopy of diffuse reflection in the region 0.5–5.0 eV, accelerated aging of pigment compositions with synthetic materials used in restoration of paint layers of paintings is investigated. Composition containing pigments zinc and titanium oxides (white pigments), chromium oxide and copper carbonate (green pigments), and iron oxide (brown pigment) and reinforcing materials vinyl acetate-ethylene copolymer, fluorolon F-42L, and polyvinyl alcohol are investigated. It is established that the appearance of color in pigment impregnation and subsequent heating is observed only in the compositions of reinforcing materials with white pigments and occurs as a result of heterogeneous reactions that lead to the formation in the pigment of color centers bonded by oxygen vacancies. Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 64, No. 4, pp. 518–522, July–August, 1997.     

A multi-analytical study of the fifteenth century mural paintings of the Batalha Monastery (Portugal) in view of their conservation

The systematic characterization of the painting’s palette and technique applied on the execution of the mural paintings of the Batalha Monastery (Batalha, Leiria, Portugal) is presented. These are the oldest mural paintings known in Portugal (apart from Roman frescoes) and represent the beginning of an artistic Portuguese tradition that continues until the nineteenth century. The aim of the study was to identify for the first time by adopting a multi-analytical physico-chemical approach of the pigments, binder, and alteration products (white veils, crusts, and pigment alteration) of these unique works of arts in order not only to better understand the painting technique, but also to support a conservation-restoration intervention that took place from April to August 2010. Micro-sampling of paint layers was performed on representative areas of the paintings. The characterization of the pigments and binders was carried out by microscopy and microanalysis of cross sections using optical microscopy, scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM-EDS), micro-FTIR, and micro X-ray diffraction. The combined analysis of the paintings allowed the identification of the painting’s palette: Vermillion (HgS) and red ochre for the reds, yellow ochres for the yellows, green earths and malachite for the greens, azurite for the blues, and carbon for the blacks. The use of the pigment is dependent of the motive painted while the most expensive materials were used in the most important iconographic motives. Alteration of malachite was identified in darkened layers in green areas of the paintings. White veil areas on the surface of the paintings were identified as calcite from precipitation/dissolution processes due to water run-off on the sacristy dome ceiling and walls.     

故宫奉先殿清初彩画颜料成分分析

故宫奉先殿是明清两代皇帝祭祀祖先的家庙,地位仅次于太庙。奉先殿始建于明成祖时期,现存建筑主要建于康熙时期,其上保留了为数不多的清初彩画,是研究清初彩画的珍贵实物。利用显微观察、扫描电子显微镜能谱和激光拉曼光谱分析,对取自奉先殿的彩画颜料进行分析鉴定。结果表明,奉先殿彩画中部分红色和蓝色颜料层存在分层现象,表层颜色鲜艳明亮,中层和下层颜色偏浅,每层所用颜料配方不同。红色颜料有朱砂、铅丹和铁红,绿色颜料均为氯铜矿,蓝色颜料均为石青,用铅白打底。浅色颜料由主显色矿物颜料加入以铅白为主的白色颜料混合调制而成。其中浅红色由铅丹与铅白调和而成,浅绿色由氯铜矿与铅白调和而成。浅蓝色颜料中未发现铅白,但含有大量Al元素和Si元素,推测含有高岭土。浅蓝色颜料有可能是由石青与高岭土调制而成。奉先殿彩画中未发现清晚彩画常用的合成群青、巴黎绿等颜料,反映出奉先殿彩画的绘制年代很有可能就是档案记载的康熙年间,之后未有大修。高岭土作为白色颜料调配浅色颜料在彩画制作中比较少见,奉先殿彩画中高岭土的发现丰富了清代早期彩画颜料制作的资料,具有一定的学术意义。