Identification of Pigments in Colored Layers of a Painting by Raman Spectroscopy

Using the method of Raman spectroscopy the pigment composition is investigated of, and the brushwork technique used in, the original layer of a 19th century painting is established. It is an overdoor worked, presumably, by Antoine Jean-Etienne Faivre. It is established that the artist used the following pigments: cinnabar and dyes on the basis of goethite and hematite (for red, yellow–orange, and brown shades), ultramarine and Prussian blue (for blue shades), and Emerald green and a mixture of blue and yellow shades (to obtain a green color). It is determined that white lead was used a primer.     

西藏扎什伦布寺壁画的科学研究

壁画是寺院建筑的重要装饰元素,也是藏传佛教艺术的重要组成部分。扎什伦布寺始建于明正统12年（公元1447年）,作为后藏最大的寺院,寺内保存了大量精美壁画,这些壁画对研究藏传佛教及佛教艺术具有重要意义。扎什伦布寺自建寺起一直为传播佛教文化服务,经历了频繁的大规模修建。为了解扎什伦布寺壁画的制作材料与工艺,为今后壁画的保护及修复提供重要的参考及科学支撑,选取寺内强巴佛殿四层北壁、吉康扎仓南殿西侧的典型壁画,共采集8个样品。采用超景深三维视频显微镜观察壁画的制作结构,显微激光拉曼光谱仪对有机与无机颜料的成分信息进行表征,偏光显微镜根据晶体的光学信息鉴别拉曼光谱相似的颜料颗粒,X射线衍射仪用于测定地仗成分,扫描电镜/能谱仪则对微观数据进行确认和补充。通过分析研究,壁画由地仗层、准备层、颜料层构成。颜料包括矿物及人工合成颜料,其中红色颜料为朱砂与颜料红14,绿色颜料为块铜矾、酞菁绿,黑色颜料为碳黑,黄色颜料为雌黄,蓝色颜料为合成群青。颜料红14与酞菁绿为有机合成颜料,合成群青则为无机合成颜料。块铜矾作为矿物颜料,在欧洲曾用于架上画、壁画、手稿等艺术作品中,但在国内还未曾发现其使用历史,这一发现扩展了对绿色颜料的认识。壁画的地仗层依据藏式壁画制作传统使用了阿嘎土,准备层则由黄土制备。研究结果表明,壁画制作时以阿嘎土打底,刷一层黄土找平壁面,以胶调和颜料绘制于黄土层之上。壁画除了使用一些常见的传统藏式壁画材料,还发现了一些近代人工合成材料,说明扎什伦布寺强巴佛殿四层北壁及吉康扎仓南殿西侧壁画曾经历过重绘或补绘。该研究结果不仅弥补了扎什伦布寺壁画的研究空缺,也为扎什伦布寺修缮历史的补充及完善提供了重要证据。     

西藏拉萨大昭寺转经廊壁画颜料的拉曼光谱分析

利用显微激光拉曼光谱仪对大昭寺转经廊壁画颜料进行了分析。结果表明,壁画使用的红、黄、蓝、绿和白色颜料有朱砂、铅丹、甲苯胺红、雌黄、铅铬黄、铁黄、石青、群青、石绿、水胆矾、巴黎绿、菱镁矿、立德粉和方解石。首次发现壁画中使用了合成有机颜料甲苯胺红。检测分析结果提供了准确可靠的资料,有助于清晰认识不同时期壁画绘制和修复所使用颜料成分。     

Testing of Raman spectroscopy as a non‐invasive tool for the investigation of glass‐protected pastels

Five French pastels and a sanguine drawing dating from the 17th to the 20th century were studied by Raman spectroscopy. Different operative conditions were used: the pastels were investigated through their protective glass, and the results obtained were compared with those obtained after removing the glass and after sampling a micrometric particle of pigment. Different parameters (wavelengths, powers of excitation and objectives) were tested in order to assess the optimal procedure of analysis for this fragile work of art. The results obtained for black (carbons), yellow (chrome/cobalt yellow), red (lead oxide, vermillion, orpiment), brown (red lead and chrome yellow), blue (Prussian blue, lapis lazuli/ultramarine), green (mixture of above blue and yellow pigments) and white (calcite, lead white, anatase) pigments are presented and the consistency of the pigments' period of use with the dating proposed for each pastel is evaluated. In one of the pastels, the blackening of the carnation colour made of an unstable mixture of lead white, red lead and vermilion was studied. Copyright © 2010 John Wiley & Sons, Ltd.     

清代工笔云龙水波纹绘画颜料及技法研究

利用超景深三维视频显微镜、激光显微共聚焦拉曼光谱仪、能量色散型X射线荧光分析显微镜,对一幅清代工笔画中云龙纹、水波纹所用颜料及技法进行研究。实验结果表明,画作中人物衣服首先以人工合成颜料巴黎绿（Paris green,Cu(CH₃COO)₂·3Cu(AsO₂)₂）整体填色,再用铁红（Hematite,α-Fe₂O₃）描绘出云龙纹、水波纹,绿色、红色颜料共同呈现纹饰内区的暗黄色,此后再以Cu-Zn-Pb合金黄铜粉末勾描出“金边”。此外在画作中还发现了人工合成的群青（Ultramarine,(Na, Ca)_7-8(Al, Si)₁₂(O, S)₂₄[SO₄, Cl₂(OH)₂]）,结合巴黎绿、群青合成成功的年份,确定了画作完成的时间上限。     

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.     

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.     

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.     

唐代苏同家族墓天王俑彩绘的光谱分析

天王俑是中原地区的达官贵人墓葬的镇墓俑,是唐墓葬冥器中重要的一种神煞俑。为探究天王俑彩绘颜料的组成元素以及彩绘工艺,使用X射线荧光光谱分析了陕西省咸阳市渭城区苏同家族墓KTJ-2019-019M2、 KTJ-2019-019M3坑出土的天王俑彩绘区域的元素组成。分析结果表明陶俑表面金色贴片主要为金箔(Au);红色颜料的组成元素则是Hg、 S以及少量的Pb、 P;蓝色颜料和绿色颜料的组成元素均为Cu,白色颜料的组成元素为P、 S、 Pb。使用拉曼光谱对彩绘颜料层的鉴定物相,使用拉曼光谱分析技术对彩绘层分析结果确定了红色颜料的主要组成物相为朱砂(HgS)和铅丹(Pb₃O₄)的混合颜料;蓝色颜料的主要组成物相为石青;绿色颜料的主要组成物相为石绿;白色颜料的组成物相可能为铅白。进一步使用XRF面扫描技术分析了天王俑的彩绘工艺,解析金、红、蓝、绿色区域的组成元素位置,发现陶块样品中的M₂-1金色陶块、 M₃-1白色陶块、 M₃-2红色陶块、 M₃-3蓝色陶块、 M<...     

MA-XRF study of 15th–17th century icons from the collection of the National Museum in Krakow,Poland

In 2015, the National Museum in Krakow, Poland, started a grant from the National Programme for the Development of Humanities, its goal to investigate an important collection of old Orthodox painting, including more than 50 15th to 17th century icons originating from the territory of the historical Orthodox Diocese of Przemyśl within the borders of the Polish Kingdom. The aim of researching the iconography, provenance, and technology of the artworks was to describe their specific features and destination, in detail, and to characterise their artistic milieu. Many different techniques were used during research, such as X-ray fluorescence (XRF), X-ray diffraction, reflectography, radiography, ultraviolet–visible imaging, Fourier-transform infrared spectroscopy, scanning electron microscopy with energy-dispersive X-ray spectroscopy of prepared paint layer cross sections, and dendro-chronological analysis. This paper focuses on highlighting the advantages and disadvantages of the spatially resolved macro-XRF scanning (MA-XRF) technique. Most interesting results concluded from elemental distribution maps obtained through the use of Bruker, M6 Jetstream MA-XRF scanner include the following: characterisation of the type of gold and silver foil used in the icons; determination of main pigments, including the use of lead tin yellow unusual in iconography; and the noting of an interesting distribution of blue pigments as well as the presence of orpiment. Surprisingly, a considerable amount of zinc with azurite addition was observed in brown layers. The results obtained primarily highlight all the typical features of local Carpathian icon craft.     

An example of the complementarity of laser‐induced breakdown spectroscopy and Raman microscopy for wall painting pigments analysis

Laser‐induced breakdown spectroscopy (LIBS) and Raman microscopy were used for the identification of pigments in wall painting. Raman spectroscopy, which provides the molecular ‘fingerprint’ of the compound, is nowadays widely used by the archaeometry community, especially for pigment analysis. LIBS, which provides the elementary composition of samples, is a rapid noncontact method, enabling layer‐by‐layer analysis through a precise laser ablation of the sample. This work deals with the behavior of pigments after a LIBS analysis, by trying to identify the compounds before and after the laser shot. Six commercial pigments prepared with the fresco technique were investigated: ultramarine blue, red lead, charcoal, a yellow and a red ochre, and a green earth. Raman spectra, acquired on the sample surface and in the crater induced by LIBS analysis, were compared. The results show that these pigments are well recognized after a LIBS measurement. The analysis of green earth illustrates that the combination of these two techniques gives complete information from a sample. Copyright © 2007 John Wiley & Sons, Ltd.     

Analysis on Mural Structures and Components of the Tombs in Liao Dynasty (A.D. 907–A.D. 1125)

The compositions of plaster, pigments, and binding medium were identified using micro-Raman spectroscopy, scanning electron microscopy coupled with energy-dispersive X-ray, and gas chromatograph-mass spectrometer. The results show that the plaster was calcium carbonate; the red color was ascribed to hematite; the blue pigment was ultramarine; the black pigment was carbon; and the yellow pigment was litharge. Animal glue as the binding medium was mixed in the pigments. Dissolved salt (mirabilite) was confirmed on the tomb passage. The mural detachment was detected with portable infrared thermal imager, and this damage resulted from the soil layer. This will serve as the basis for repairing the murals and reliable methods for identifying ancient murals.     

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.     

A scientific approach to the characterization of the painting materials of Fra Mattia della Robbia polychrome terracotta altarpiece

During the last restoration (2008–2011) of the polychrome terracotta altarpiece called Coronation of Virgin between Saints Rocco, Sebastian, Peter martyr and Antonio abbot, located in the collegiate church of S. Maria Assunta in Montecassiano (Macerata, Italy), scientific investigations were carried out to acquire detailed information about the painting technique. The identification of materials allowed a correct restoration. The altarpiece is almost entirely realized by Marco della Robbia (Fra Mattia), dates back to the first half of the XVI century and represents an interesting example of painted terracotta produced by using two different techniques: glazed polychrome terracotta and the “cold painting” technique. The characterization of the samples’ material constituents was obtained by analysing the cross-sections and the fragments by different techniques (optical, SEM-EDS and ATR-FTIR microscopy as well as GC-MS), as the real nature of a component is often difficult to assess with one single technique. The optical microscope examination of paint cross-sections shows the presence of many layers, indicating the complexity of the paint stratigraphic morphologies. The original polychromy of della Robbia’s masterpiece is constituted of cinnabar, red lake, red lead, orpiment, red ochre, lead white, lead tin yellow, green earth and raw umber. Two different types of gilding technique have been distinguished. The first one presents a glue mordant, and the second one shows an oil mordant composed by a mixture of red lead, red ochre, cinnabar and orpiment. The GC-MS analysis allowed the characterisation of linseed oil and a mixture of animal glue and egg as binding media stratigraphically located by the use of ATR-FTIR mapping microscopy. The analytical results of the painted terracotta integrated investigations show that original technique adopted is characterised by the application of pigments in an oil-binding medium directly applied on the substrates, probably treated with oil and animal glue. A large number of overpaintings above the original scheme of polychromy was found, which could be ascribed to almost three different interventions; the absence of modern pigments suggests that they could be realized long ago.     

青海热贡地区传统建筑彩画颜料光谱特征分析研究

青海省热贡地区是安多藏区藏式建筑彩画艺术的重要产地,作为热贡艺术的重要组成部分影响甚广。热贡地方建筑彩画不仅是附着建筑栋梁之上的艺术瑰宝,更是一项延续至今的传统技艺,至今仍有大批传统匠人画师从事相关行业。热贡地方建筑彩画有独立的用色方法和颜料制作工艺,对其所用传统颜料进行科学检测是系统研究该地区建筑彩画的基础性工作,在进一步研究热贡地区建筑彩画的制作工艺和艺术特色,传承地方建筑彩画技艺和完善保护政策等方面具有积极意义。通过对同仁市隆务寺夏日仓行宫火供殿所用当地传统建筑彩画颜料的采样,运用X射线荧光光谱、X射线衍射分析、激光显微拉曼光谱分析等多种实验分析方法,对颜料样品进行分析,测定其主要显色物质和成分占比。结果表明,热贡地方建筑彩画所用颜料多为无机颜料;蓝色颜料主要是人造群青;绿色颜料的主要矿物组成为绿土,显色物质为蒙脱石,存在将植物色染料加入当地所产的富镁蒙脱石中混合使用的可能性;红色颜料的主要矿物组成为铁红（赭石类红土）,通过焙烧富铁矿土来人工合成,材料来自于当地吾屯村所产红色赭石类粘土;黄色颜料主要矿物组成为密陀僧、硫磺及其他植物色染料制备而成;黑色颜料为碳黑,符合木炭黑的性状特征;白色颜料主要为生石灰及氧化镁粉,并在其他颜料中广泛使用石灰及氧化镁粉作为调色颜料;推测部分样品中含有包金土及植物色素染料、其他人工合成颜料的可能性。整体来看,热贡地区建筑彩画所用颜料成本价格较低,制取难度不大,来源大多是当地常见的矿土料和动植物染料,传统的制料工艺较简单,颜料多呈现为组分复杂的混合物状态;密陀僧、包金土和群青等颜料多来自于内地及国外,颜料人工合成的历史较早,反映出热贡地区建筑彩画在颜料使用上不仅使用本土材料制备,也广泛使用外来颜料的历史传统,为进一步研究热贡地区建筑彩画领域内汉、藏等多民族文化交往、交流、交融历史提供了良好实证材料。     

Non‐destructive identification of pigments printed on six Imperial China Engraved Coiling Dragon stamps

Raman spectroscopy was employed to investigate six Imperial China Engraved Coiling Dragon stamps non‐destructively. The results have shown that (1) the main colors (yellow, green, scarlet, brown, vermilion, and blue) on the six stamps were all prepared from inorganic pigments, including chrome yellow, chrome orange, Prussian blue, red lead, magnesium sulfate hydrate, and ultramarine blue. (2) Raman spectrometer has been allowed for successfully identifying the molecular structure of the pigments printed on the six examined stamps, suggesting that such a dual analytical approach could satisfy the need for pigment identification on stamps. (3) The finding that certain pigments were intentionally mixed to produce a whole different hue or color, the mechanism of which could be explained by theories of chromatology and metamerism, also provides new insight into the future conservation, authentication, and restoration of the early printings. Copyright © 2015 John Wiley & Sons, Ltd.     

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.     

Analysis of mural paintings using in situ non‐invasive XRF,FTIR spectroscopy and optical microscopy

An analytical protocol consisting of X‐ray fluorescence spectroscopy, optical microscopy and Fourier transform infrared spectroscopy was used to study the origin and the nature of the materials (pigments, binders and coating preparation) of the Fundenii Doamnei church mural paint from Bucharest. The main interest of the present study consisted in the original votive paint from narthex, painted in 1757 in a secco technique. During analysis, an unexpected pigment in the votive paint could be detected by the combined analytical techniques: ultramarine blue. Along with this pigment, the presence of gypsum binder based on egg and flax seed oil could also be evidenced. These results demonstrated a secco execution technique of the votive paint and also the presence of a restoration treatment. Moreover, during the present study, the components of the preparation layer and the constitutive pigments from both 1699 and 1757 years mural paints have been analyzed. Hence, the following pigments could be identified: vermilion, azurite, cinnabar, lead white, ochre, natural umber and gold, by using the combination of the analytical techniques. The novelty of our results consists in detecting the composition of the materials used in this church painting (fresco and a secco) during these 254 years since its first restoration. The results of these investigations pointed to the suitability of the non‐destructive and semi‐destructive analytical techniques in the complex characterization of the paints realized in different techniques, at different periods. Copyright © 2013 John Wiley & Sons, Ltd.     

Spectroscopic investigation of modern pigments on purportedly medieval miniatures by the ‘Spanish Forger’

Five miniatures by the so‐called ‘Spanish Forger’ were acquired by the Victoria and Albert Museum in 2008. Believed to be authentic medieval miniatures until the mid‐twentieth century, they are now considered to have been painted around the end of the nineteenth and the beginning of the twentieth century. To investigate this attribution and to gather detailed knowledge about the materials used by the artist, a comprehensive pigment analysis by Raman microscopy and X‐ray fluorescence was carried out. Although traditional materials such as vermilion, carbon black, red lead, lead white and indigo were identified, many others (chrome yellow, Scheele's green, emerald green and ultramarine blue) are modern and synthetic pigments, a result which provides a firm scientific basis for stating that the miniatures are forgeries. Copyright © 2009 John Wiley & Sons, Ltd.