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Pigments & dyes in a collection of medieval illuminations (14th-16th century)
Abstract
The Marcadé Collection (Bordeaux Cathedral treasury) consists among other objects of 42 illuminations (14th to the 16th century) from 5 origins (France, Italy, Germany, the Netherlands, and Spain). For better knowledge of these miniatures, the pigments and dyes have been analyzed in ten illuminations chosen in order to represent the diversity of the collection. The aim of this study is to establish a panorama of the pigments and techniques used in medieval miniatures through the study of a set of manuscripts and to discuss the potentialities of the analytical techniques in order to reach this objective.
Hyperspectral imaging is a rapid, mobile and non-invasive technique. It gives reflectance spectra for each pixel of the image. The datacube obtained was treated in order to visualize images and reflectance spectra. The software allows the mapping of the pigments by comparing spectra with those of our database. As some interpretation difficulties can appear for dyes or mixtures, to confirm the identification, point techniques such as Raman, X-ray spectroscopy and Fiber Optic Reflectance Spectroscopy in the Near Infrared range were used.
Analyses allowed access to the palette for each illumination and showed the colours diversity and pigments treatment. They increase knowledge about the materials used and the evolution of them during the time period: the use of dyes and shell gold became more important at the end of the period. The analytical choice respects the fragility and preciousness of these artworks and helps the fast data acquisition for the materials identification.
Keywords: hyperspectral imaging; colours; pigments; dyes; miniatures.
... Elemental, molecular and imaging techniques are combined in order to yield as most complete information as possible concerning the materials and the techniques used by ancient artists. Considering only the last two years, good examples are the studies by Cucci et al. (2018), Fruhmann et al. (2018, Legrand et al. (2018), Mounier andDaniel (2017) andde Viguerie et al. (2018). In this study, a combination of molecular (UV-visible diffuse reflectance spectrophotometry with optic fibres and Spectrofluorimetry), elemental (X-Ray Fluorescence spectrometry) and visual (optical microscopy) techniques yielded a vast amount of information; in addition, the application of mass spectrometry using the eZooMS (electrostatic Zooarchaeology by Mass Spectrometry) method provided information on the preparation of parchment. ...
... Elemental, molecular and imaging techniques are combined in order to yield as most complete information as possible concerning the materials and the techniques used by ancient artists. Considering only the last two years, good examples are the studies by Cucci et al. (2018), Fruhmann et al. (2018, Legrand et al. (2018), Mounier andDaniel (2017) andde Viguerie et al. (2018). In this study, a combination of molecular (UV-visible diffuse reflectance spectrophotometry with optic fibres and Spectrofluorimetry), elemental (X-Ray Fluorescence spectrometry) and visual (optical microscopy) techniques yielded a vast amount of information; in addition, the application of mass spectrometry using the eZooMS (electrostatic Zooarchaeology by Mass Spectrometry) method provided information on the preparation of parchment. ...
The manuscript D.I.21 kept at Biblioteca Nazionale Universitaria in Torino, better known as Messale Rosselli, is one of the richest fully illustrated missals surviving from the mid-14th century. It was produced in Avignon for the Aragonese Cardinal Nicolas Rossell (1314–1362) but after the patron's death, it passed from hand to hand until it reached its final destination in Torino. The Messale Rosselli has recently been the object of a thorough interdisciplinary study, involving full characterisation of the colourants with non-invasive techniques (FORS, fluorimetry, XRF spectrometry, optical microscopy, IR photography). The full set of colourants was identified, highlighting the systematic use of precious pigments such as lapis lazuli, cinnabar and gold, a feature reinforcing the symbolic value of the manuscript; in addition, less valuable but interesting dyes such as brazilwood and folium were also identified, used either pure or in a mixture with pigments in order to obtain a wide range of hues. The palettes used by the various artists have been evaluated according to the availability of raw materials in the geographic area around Avignon, finding that most of the colourants could be at easy disposal of the artists. Information has also been obtained concerning the preparation of the parchment. The systematic measurement of the width of folios allowed hypothesising the number of the animals slaughtered to produce parchment, and the way of using skins. XRF analysis on the folios suggested that different preparations were used. Finally, eZooMS, a non-invasive technique able to provide information on the animal species from which parchment was produced, evidenced that calf and goat, but not sheep, were used to produce the parchment of the Messale Rosselli.
... Apart from copper being detected, other elements associated with the green are zinc in Fr 26692 and chlorine in the green of Fr 10156. Chlorine has been associated with a peculiar element of the salt used in the production process of the so-called 'salt verdigris', where copper is enclosed for a number of days coated with honey, salt, and vinegar 38 . It has been identified in the green colour of, for instance, a German illumination from the 16th century, and in some greens in the 12th century Bury Bible, from Bury St. Edmunds, England 10 . ...
The palette and constituting materials of several medieval parchment fragments coming from books thought to be locally produced in Sweden have, for the first time, been examined by non-invasive methods for chemical and physical characterization. These books were primarily used in medieval Swedish parish churches (including present-day Finland), and they could be said to represent everyday book culture of the time. Ten fragments from the collections of the National Archives of Sweden dated to the 12th to the 15th century were studied by microscopy, hyperspectral imaging in the visible and ultraviolet range, X-ray fluorescence spectrometry, reflectance spectroscopy in the UV, visible and near-infrared range, external reflectance in the mid- and near-infrared and Raman spectroscopy. Pigments, colourants, and inks have been characterized and identified. The aim was to enhance the understanding of these objects and to evaluate the value of technical analysis, the results of which, when combined with historical and palaeographic studies, will advance the comprehension of medieval Nordic book culture. The results reveal the presence of many of the materials commonly used in book production in Europe at the time, such as vermilion, red lead, azurite, orpiment, and copper-based greens, and also some more unusual substances. The colourant components evince significant variation, and it appears likely that they were largely received via trade routes and learned networks from various European locations. The documents from the 12th century differ from the others in their substances and practices, such as the use of ultramarine for calendar rubrics and the varied use of different reds and greens. There is an unusual use of an iron-based red with copper particles for initials, green earth for initials, organics for highlights, and a probable tannin writing ink with neither iron nor carbon.
... The latter allow to consolidate the identification of materials in case that doubts remain about the interpretation of the spectra acquired by the hyperspectral camera de Viguerie et al., 2018). The advantages of the hyperspectral imaging make it an essential device for the non-invasive study of various colored media such as wall paintings Cucci et al., 2020;Laclavetine et al., 2020), manuscripts and prints (Mounier and Daniel, 2017;Mulholland et al., 2017;Pérez-Arantegui et al., 2018;Biron et al., 2020), easel paintings (Delaney et al., 2010;Daniel et al., 2016;Delaney et al., 2016b;Delaney et al., 2020) but also textiles (Delaney et al., 2016a;de La Codre et al., 2021). On the contrary, the application of this analytical technique to decorated ceramics is relatively uncommon. ...
During the second half of the 19th century, the production of ceramic pieces decorated with relief polychrome glazes occupied a prominent place in French factories of white earthenware. It is through the example of the Vieillard and Co Manufactory (Bordeaux, France, 19th century) that we will approach the technical study of this ceramic decoration process. A corpus of seven fragments of glazed earthenware from archaeological excavations, that took place in the waste dumps of the Vieillard and Co manufactory, has been studied. A multianalytical study (SEM-EDS, PIXE-PIGE, and hyperspectral imaging) was carried out in order to characterize both the clay support and the colored glazes. A second part of this research concerns the development of optical techniques based on reflectance spectra and hyperspectral imaging. This non-invasive method is intended to characterize colored glazes and more specifically, to identify the type of pigments used. All the data obtained made it possible to better understand the nature of the decoration chromogens and thus, to establish the color palette of the artists who produced this type of decorative objects. Therefore, one of the aims is to build a preliminary database established on hyperspectral imaging, which will then be used when studying ceramic objects that can not be sampled.
... Spectral fingerprints can also be used to identify pigment recipes and map their distribution on painted surfaces (Cucci et al. 2020). HSI in the VIS-NIR range can detect pigments and dyes on fragile materials such as miniatures, engravings, tapestries, and paintings (Cucci, Delaney, and Picollo 2016;Gabrieli et al. 2019;Mounier and Daniel 2017;Mounier, Denoël, and Daniel 2016;Mounier et al. 2018) and has been used as an exploratory method for highlighting similarities or dissimilarities in the composition of materials and setting sampling strategies for further elemental analysis. ...
This paper discusses the use of a small ultraportable hyperspectral camera in the VIS-NIR (Visible-Near Infrared) range for archaeological fieldwork and its hardware, data processing workflows, and spectral information that can be used for in situ screening. Hyperspectral imaging is a widespread, non-destructive analytical technique used in various disciplines for highlighting invisible patterns and mapping the spectral signatures of selected targets. In archaeology, it has mostly been applied for remote sensing satellite imagery to uncover information about features that are hidden underground. Targeted applications of hyperspectral imaging have been developed in the last few years, opening new perspectives for material analysis based on spectral mapping. Recent advances in portable instrumentation have led to the development of small and rugged cameras that can be used directly in the field for investigating different materials.
... The additional maximum at 630 nm for the purple areas is attributed to the blue colourant in this pigment mixture and can also be determined for the blue areas of the illuminations, which is characteristic of two pigments, azurite and ultramarine (Mounier & Daniel, 2017). Since the XRF spectra from both colourants show no signal for copper (Cu), we can exclude azurite (Cu 3 (CO 3 ) 2 (OH) 2 ) beyond any doubt and thus identify the blue pigment as a type of ultramarine. ...
The illuminations in two Italian manuscripts are still a mystery today. Both manuscripts were based fully or partly on the Florentine Squarcialupi Codex (Florence, Biblioteca Medicea Laurenziana, Med. Pal. 87) dating from around 1410/15. With the help of a multi-analytical, non-destructive approach employing mobile instrumentation (XRF spectroscopy, visible reflectance spectroscopy and infrared reflectography), we examined the manuscripts Toronto, Thomas Fisher Rare Book Library, MSS 09700 and Düsseldorf, Kunstpalast, Inv. K 1925-67 for the first time with regard to their production processes. The identification of modern pigments allows them to be contextualized in illumination practices of the 19th century. Manuals of that time provide a wealth of information on specific illumination practices and the availability of writing and painting materials, which correlates with the actual artefacts.
... The recognition of material culture in paintings through a non-destructive test (NDT) is highly desirable. In general, spectroscopic analysis has a wide range of applications for the investigation of manuscripts and miniatures (Grim and Allison 2004;Mounier and Daniel 2017;Mastrotheodoros et al. 2020). For example, visible spectrophotometry, as a non-destructive analysis, is used to characterize different colorants in artworks and the recognition of painters' palettes (Hahn et al. 2004;Paradisi et al. 2012). ...
The color red has been widely used in Miniatures as one of Persian art's most well‐known aspects, remarkable for its stability. This research investigates the preparation of vermilion as one of the most suitable colorants that produces red. So, eight vermilion samples were reproduced based on three recipes from the Safavid era (AD 1501‐1736) and colorimetrically compared with those vermilion targets selected from six Safavid illustrated manuscripts using the ΔE*ab color difference formula. Results showed that the reproduced vermilions colorimetrically match the targets while adding some Ocher amounts improves their tonality for color matching purposes.
... With Raman spectrometry the pigment applied could be confirmed as indigo (Fig. 6b). In the green areas of this codex (Fig. 5a, saint MP5 and lion MP8) copper (Cu), sometimes associated with chlorine (Cl), was detected, but no clear identification of the paint material could be achieved [39][40][41]. Similar difficulties occur in the case of the brown pigments, where by XRF just iron (Fe) was registered as the main element, but no evidence for the used pigment was found (Fig. 5a, lion MP4 and MP5). ...
Two precious Carolingian manuscripts kept in the library of Kremsmuenster Abbey in Upper Austria were subject of investigation. The well-known Codices Millenarius Maior (Inv. No. CC Cim 1, Fig. 1a) and Millenarius Minor (Inv. No. CC Cim 2, Fig. 1b) were studied within the framework of the Centre of Image and Material Analysis in Cultural Heritage (CIMA) in Vienna. The manuscripts are especially famous for their precious and colorful miniatures of a very early medieval period. The aim of the work was the material identification (colors and inks) used for the make-up of the two codices in order to gain a better understanding of their evolution and their provenance. The instrumentation available in the CIMA laboratories allowed performing in situ measurements using non-destructive and non-invasive analytical methods. The investigations comprised a combination of three complementary methods: X-ray fluorescence analysis (XRF), Fourier transform infrared spectrometry in the reflection mode (rFTIR) and Raman spectrometry. In addition to the identification of the pigments and inks also a detailed characterization of the parchment concerning its manufacturing process was achieved by that combination. The identification of calcium carbonates on the surface of the parchment is an indicator for the liming or whitening of the animal skin, whereas the polishing process of the parchment surface with pumice stone, left traces of silicates, detected by rFTIR. The combination of XRF and Raman spectrometry enabled the characterization of black/brown inks in the text revealing the usage of iron gall inks. For the red inks applied for text and initials vermilion and red lead were applied in both codices. Furthermore, the pigment palette used for the illumination included: lead white, orpiment/realgar, red lead, vermilion and red iron oxides as well as azurite and indigo, together with the rather rare copper chloride hydroxide. Furthermore, in both gospels the application of metal leaves as well as powders made of silver–copper and gold–copper alloys could be determined by XRF on several folios.
In Ancient Greece, architecture and sculpture were painted. Nevertheless, the appearance of the colors used to decorate buildings remains largely unknown due to lack of evidence. The Temple of Apollo at Delphi, is no exception to this situation. Since its discovery in 1894, the question of polychromy has been partially studied. This situation can be explained by the difficulty of detecting pigments directly on the ancient blocks by simple visual observation. The majority of them are imperceptible to the naked eye. This paper aims to put a exploratory methodology based on archaeometric, photogrammetric and computer analyses in order to the locate, characterize traces of polychromy that are invisible to the naked eye and to provide new data that can be used to reconstruct the architectural polychromy of the Temple of Apollo at Delphi in the late classical period.
A hemispherical stone has been discovered in a 19th century ruined barn at the village of Lacapelle Livron (Tarnand Garonne, France). Its morphology and its mirror polished flat surface showing numerous picketing marks allow to propose a grinding function. Optical microscopic observation shows that numerous striations and de
pressions present on the main flattened surface are resulting from a grinding action on a hard material. Further investigation with SEM-EDS analysis revealed high quantity of cinnabar pigment spreaded on the whole working flat surface and minor traces on other sides, indicating that the stone have been used as a muller to process pigment. Minor incidental traces of orpiment and calcite and an undetermined black organic residue analysed on a smaller flattened side are probably in relation with a second step of pigment processing. Additionally, many
vegetal micro-fragments and micro-fibres have been observed in relation with the main working surface and red pigment. Identification of cotton among this fibre material is suggesting a late medieval or renaissance dating. Other observations and analysis put also in evidence iron striated and lined residues on the stone surfaces which could have resulted from the contact metal tool (i.e., knife) used to pick pigment, and from a handle or from the storage in a box. At last, comparison of the artefact can be done with historical pigment mullers from 18th–19th century and representation of painting workshop between the 15th and 17th century can help to propose different possible contexts of usage of this tool.
The study of organic materials used on fragile artworks (manuscripts, tapestries…) needs fluorimetric studies for their identification. Especially when the sampling is prohibited and when the artworks cannot be brought to the laboratory. However, laboratory systems have a limited analysis chamber making it very difficult to make measurements on artworks. A portable spectrofluorimeter using LED sources (LEDμSF) was therefore designed, patented, and its performances have been proven for the characterization of materials of artworks of Cultural Heritage. The development of the LEDμSF demonstrates to be a good solution to record quickly in situ fluorescence emission spectra and a good complementary method beside hyperspectral imaging.To facilitate the interpretation of the results, a database including reference fluorescence emission spectra was built. The work was done on a large selection of pigments and dyes deposited on various supports such as quartz slides, parchment, and fibres. The samples were often made according to recipes described in old treatises. The ageing of materials is also considered while taking into account the advantages and limitations of the method.The efforts of development of this handheld fluorimeter, its applications and the complementarity with other portable spectroscopic techniques are summarized here through some examples of applications on case studies (mediaeval miniatures, Japanese engravings, tapestries, and Siberian clothes).KeywordsArtwoksDyeFluorescence emissionPigmentPortable fluorimeter
Purpose
This paper aims to present the components' characterization and condition assessment of an important deteriorated Mamluk-illuminated paper manuscript housed in Al-Azhar Library, Egypt.
Design/methodology/approach
Different analytical techniques used in this study were the portable digital optical microscope, stereomicroscope, scanning electron microscope with EDX (SEM.EDX), portable X-ray fluorescence (pXRF), X-ray diffraction (XRD), pH measurement and Fourier transform infrared spectroscopy (FTIR).
Findings
The results obtained by different microscopes showed that the gilding in the surface of illuminated paper sheets was performed with gold leaves. Additionally, these microscopes revealed that the illuminated paper manuscript has different aspects of deterioration such as adhered dirt, staining, some micro-cracks, cracks and detachment of some parts in some illuminated areas. The results of elemental analysis by EDX, portable XRF and XRD analysis showed that the orange red pigment is red lead (Pb 3 O 4 ), blue pigment is azurite (2CuCo 3 .Cu (OH) 2 ), and the gold layer is has consisted of brass alloy (Cu-Zn) with a small amount of gold element (Au). The pH measurement stated that the historical paper in the acidity level. The ATR-FTIR analysis also revealed the oxidation of cellulose. Moreover, it was found from ATR-FTIR that Arabic gum was used as a binder for the pigments.
Originality/value
This study presents the important results of analytical methods used for condition assessment and identification of the components of an important Mamluk-illuminated paper manuscript, where these results referred that the studied paper manuscript had different aspects of deterioration. The conservation steps either conservation treatment or preventive conservation are urgently needed in future studies.
Polychrome alabaster carvings, representing religious scenes, constitute England's major contribution to European mediaeval sculpture. During the period between 1350 and 1550, large number of alabaster carvings were produced in the Midlands. Despite their massive destruction during the English Reformation (ca.1534), more than 2500 of them still survive, either legally exported or sold clandestinely to the Continent. With more than 100 panels still existing, the Bordeaux region holds one of the largest concentrations of these reliefs. Most of them have unfortunately lost their medieval polychromy, but 20 can still provide valuable information. They are currently studied in our multidisciplinary research program “ALBATRES” (Polychromie, pigments, perception: les albâtres anglais de la fin du Moyen Âge conservés sur le territoire aquitain. Labex LaScArBx project [2018‐2020]). Focused on the panels' polychromy, the project links art history, archaeometry, optical and 3D engineering, and experimental archeology. The first aim is to obtain complete information on the materials and techniques used by medieval painters. The second consists in studying the functions of polychromy and its perception, by determining and interpreting the selection criteria and aesthetic uses of colors and gilding. The polychrome remains of the Aquitaine corpus are studied by means of visual examination, macrophotographic documentation, and noninvasive portable spectroscopic analyses (reflectance spectroscopy by fiber optics in visible and infrared ranges, fluorimetry, etc.). They reveal, among others, the presence of cinnabar, red lead, red ochre, copper green pigments, yellow ochre, gold, lead white, and others. The results allow the production of model samples to help understand the medieval color organization before proposing the coloring of a real copy of one of the studied panels (Virgin's Assumption, Musée d'Aquitaine, Bordeaux). The shape and the appearance of the color rendering could be improved thanks to a special device built at the IOGS to develop a shader that approximates as closely as possible the appearance of the panels. Finally, all information will be integrated on 3D model panels for better appreciation of the carvings and the artistic taste of medieval spectators.
Background
Illuminated manuscripts are complex multi-layer and multi-material objects. To this difficulty, from the analytical point of view, is added the impossibility of removing samples from these paintings for the study of their materials and techniques. There are relatively few analytical methods that satisfy these constraints as the availability of non-invasive techniques adapted to painted manuscripts is limited and mainly focused on the characterization of inorganic compounds. In the context of a research project on the analytical study of the forty miniatures in the Marcadé collection (Treasury of the Saint-André Cathedral of Bordeaux, XIII to XVI century), the potential of two non-invasive methods, hyperspectral imaging (HSI) and spectrofluorimetry is explored.
Results
The methodological development of these techniques as well as preliminary tests on miniatures recreated according to medieval recipes and materials, allowed the validation of the analytical parameters and the creation of a database of reference spectra (parchments, pigments, binders). Hyperspectral imaging associates reflectance spectra with each pixel of the image and treats the signal received in various wavelengths. The characteristics of the spectral signal in VIS range or NIR are used to get an identification and a localization of the components. It allows the study of the entire image and offers lots of ways to work: comparison of spectra, mapping, principal component analyses and false color images. Spectrofluorimetry is a sensitive method which gives information on fluorescent organic compounds under UV or visible light. Emission and excitation spectra of five red pigments in binding media have been collected. These methods were compared with X-ray fluorescence spectrometry for the qualitative analysis and mapping of the inorganic elements in a facsimile which had been purposely reproduced by an illumination painter who worked with original medieval recipes for the sake of developing the present study.
Conclusions
The combination of all these techniques allows good identification of all the materials used on an illuminated manuscript. The pertinent selection of the wavelengths used with the HSI system and a preliminary database and study of materials under UV and white light is described in this paper
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.
The use of ultraviolet and visible diffuse reflectance spectrophotometry as a preliminary technique in the investigation of illuminated manuscripts is discussed. Because ancient manuscripts are amongst the most fragile and precious artworks, characterisation of the materials used in their decoration should be performed using non-invasive analytical methods. Ultraviolet and visible reflectance spectrophotometry with optical fibres (FORS) allows non-invasive identification of several colourants used by ancient illuminators, causing no damage or mechanical stress to the artworks subjected to analysis. Identification is usually based on the comparison of analytical data with a spectral database built from painted areas on parchment, created by preparing paints according to ancient recipes as described in medieval technical treatises. Such database and the spectral features of the colourants analysed are discussed, along with the benefits of extending the spectral range of analysis into the shortwave infrared (to 2500 nm). FORS can be best appreciated as a rapid preliminary tool that offers an overview on the main colourants employed and guides the selection of painted areas of manuscripts on which more selective techniques, such as X-ray fluorescence or Raman spectroscopy, can be employed for a more complete and accurate identification.
Multispectral imaging has been applied to the field of art conservation and art history since the early 1990s. It is attractive as a non-invasive imaging technique because it is fast and hence capable of imaging large areas of an object giving both spatial and spectral information. This paper gives an overview of the different instrumental designs, image processing techniques and various applications of multispectral and hyperspectral imaging to art conservation, art history and archaeology. Recent advances in the development of remote and versatile multispectral and hyperspectral imaging as well as techniques in pigment identification will be presented. Future prospects including combination of spectral imaging with other non-invasive imaging and analytical techniques will be discussed.
A paradigm using multispectral visible and near-infrared imaging spectroscopy is presented to semiautomatically create unbiased spectral maps that guide the site selection for in situ analytical methods (e.g. fiber optic reflectance spectroscopy and X-ray fluorescence) in order to identify and map pigments in illuminated manuscripts. This approach uses low spectral resolution imaging spectroscopy to create maps of areas having the same spectral characteristics. This paradigm is demonstrated by analysis of the illuminated manuscript leaf Christ in Majesty with Twelve Apostles (workshop of Pacino di Buonaguida, c. 1320). Using this approach the primary pigments are mapped and identified as azurite, lead-tin yellow, red lead, a red lake (likely insect-derived), a copper-containing green, brown iron oxide, and lead white. Moreover, small amounts of natural ultramarine were found to be used to enhance the blue fields around Christ, and a red lake was used to highlight different colors. These results suggest that the proposed paradigm offers an improved approach to the comprehensive study of illuminated manuscripts by comparison with site-specific analytical methods alone. The choice of broad spectral bands proves successful, given the limited palette in illuminated manuscripts, and permits operation at the low light intensity required for examination of manuscripts.
This study explores the use of green pigments and mixtures in manuscript illumination, drawing upon experimental evidence derived from a non-invasive spectroscopic survey of green pigments used in 34 bound manuscripts and 23 manuscript cuttings or single folios in the collections of the Fitzwilliam Museum in Cambridge, UK. Analytical investigations were carried out on green-coloured areas by visible and near-infrared fibre optic reflectance spectroscopy (FORS), at times supplemented by x-ray fluorescence (XRF). FORS spectra can easily be acquired in great numbers and without subjecting the manuscripts to any physical strain, making this technique especially suitable for analytical surveys of valuable and fragile objects. Despite some drawbacks, its use in combination with XRF often provides a relatively complete characterisation of pigments and mixtures, particularly when FORS analysis is extended into the shortwave-infrared range (to 2500 nm). The experimental results are examined in light of the recipes for green pigments found in medieval technical treatises. The outcome is a contextualized study with a focus on French illumination between the 13th and the 16th century, but allowing for comparisons with contemporary materials of different geographic origin.
The implementation of some number of observation and analysis techniques (UV imaging, MEB/EDXS, Raman spectrometry, IRTF, spectrofluorimetry) allowed to show that gold leaf gildings, silver leaf and tin leaf were very present in the medieval mural paintings of the Southwest of France. Often these gildings localized on the characters haloes, in particular that of the Christ or the Virgin, are going to extend in numerous motives, forms and objects during the centuries. Indeed if, between the 12th and the 14th century, the leaf gilding remains discreet, for 15th and 16th centuries, the applications techniques diversify and multiply.An archaeometric study was led more exactly on three metallic decorations types: the sgraffito, the zwischgold and the applied brocade, from the point of view of the used materials, the application techniques, their organization and their location within paintings.Analyses showed that the zwischgold (gold on tin or silver on tin) was preferred for reliefs motives (stars, brooches, suns). The wax was used to model them and give them relief. The sgraffito and the applied brocade allowed to feign rich materials by imitating the motives for fabrics by means of gold leaves applied or not on tin foils, sometimes covered with glaze or with pigments.The use of these metals and techniques explains by technical, economic, symbolic reasons or by realism concern. The gold leaf, deposited according to various techniques, enriched the iconographic scenes.
The Marcadé Collection (treasury of Bordeaux Cathedral) includes 42 illuminations dating from the XIIIth to the XVIth century. Among them are three French medieval illuminations, dated about 1520–1530, never studied before. Beyond their iconographic, stylistic, and conservation study, the analysis of their materials is discussed here. Hyperspectral imaging technique is applied to characterize the pigments. The palette is composed of inorganic pigments such as azurite, red lead, cinnabar, yellow ochre, lead tin yellow, lead white, malachite, salt green and salts of copper, and also of organic pigments such as brazilwood lake, buckthorn, bucktooth and indigo. A shell gold technique is employed for the gildings. © 2016 Wiley Periodicals, Inc. Col Res Appl, 2016
Our cultural heritage is constituted by irreplaceable artworks that must be known and preserved. Their study and documentation should be in principle carried out using non-invasive approaches. The technological advances in spectroscopic imaging acquisition devices made it possible to apply this methodology to such purpose. In this context, the present paper discusses a particularly challenging task within the conservation field, which is the identification of red lake pigments in artworks, applying Vis-NIR hyper-spectral imaging spectroscopy. The latter was used to characterize and discriminate between historically accurate paint reconstructions of brazilwood (vegetal) and cochineal (animal) lake pigments. The same paints were also analyzed with Fiber Optic Reflectance Spectroscopy to validate the data obtained with the imaging method. The requirements for a successful identification of these pigments are addressed, and future research is suggested in order to increase the usefulness of the technique’s application.
(Full-text available at: https://institutodehistoriadaarte.wordpress.com/publications/rhaw/)
The fragility and small dimensions of illuminated manuscripts prohibit the use of chemical methods that rely on small samples being taken from the artwork as is typically done for paintings. Instead site-specific in situ techniques such as X-ray fluorescence (XRF) and Raman spectroscopy are commonly used to identify pigments. While the number of non-invasive analytical techniques is growing, all are site-specific and thus cannot be used to survey the entire work of art. Recently we have found that by combining results from multispectral visible/infrared reflectance and luminescence imaging spectroscopy with those from site-specific methods such as fiber optics reflectance spectroscopy (FORS) and XRF, it is possible to successfully identify and map the primary pigments on medieval illuminated leaves, as well as visualize the underlying preparatory sketches and compositional changes. Examples of the experimental workflow and results obtained by using it to study several illuminated leaves are presented.
In this work, a novel combination of portable micro-Raman spectroscopy and semi-automatic methods of data treatment are proposed for the classification and mapping of visible multispectral imaging data for the analysis of a painting on paper by Vincent Van Gogh. Analysis of multispectral imaging data with the sequential maximum-angle convex cone (SMACC) and spectral angle mapper (SAM) algorithms differentiated the surface into areas on the basis of the presence of pigment mixtures. Complementary analytical information was obtained through portable Raman spectroscopy was performed on a few selected points of the painting, allowing for the determination of Van Gogh's palette and the mapping of pigment mixtures on the painting's surface; the number of mixtures employed is varied and at least two different blues are present. The results obtained were integrated with the information from prior ultraviolet (UV)-induced luminescence analysis performed on the same painting to better understand the materials used by the artist. The mathematical treatment of multispectral data using the proposed methods could be extended to the analysis of other painted surfaces.
This is primarily concemed with the identification of red pigments by cutting thin sections of imbedded paint samples and plotting the spectral transmission curve in the visible part of the spectrum. Details are given of the imbedding procedure and the cutting of a section by a glass-knife microtome. The curves were plotted by means of a comparison microscope fitted with a variable interference filter and photomultiplier. Included is a brief outline of the chemistry of some of the main components found in various insect and plant red dyestuffs. The author presents a table of results for samples from a selection of paintings, at the end of the article.
From the results reported, the FORS device can be considered a useful and non-invasive tool for acquiring spectral information
from paintings and wall-paintings in order to identify pigments, to analyze color changes, to monitor the status-of-health,
and to detect the presence of alteration products.
Due to its dimension and weight, the FORS apparatus can be easily transported and used for collecting spectra in situ thus giving us the possibility to follow restoration work even in somewhat uncomfortable and difficult situations. Moreover,
since a large number of spectra can be recorded, it offers the possibility of a statistical treatment of the data in order
to discriminate among different compounds.
The recent advent of Mid-IR optical fibers might profitably extend in the following years the FORS domain to this spectral
region (2.5-10μm) which should provide more exhaustive information.
Water extract from rhamnus berries (Rhamnus catharticus) is the base of Stil de grain lake (also called Buckthorn lake), an ancient dye used in textiles and in paintings. In this work, the main colored component of the lake was separated and its chemical structure determined by advanced NMR techniques. The results show that quercitrin, a glucoside derivative of quercetine (3,5,7,3′,4′-pentahydroxy-flavone) is the principal colored form. This result does not agree with previous literature assignments. In this work a characterization of quercitrin in methanol and in water as a function of pH was carried out by absorption and emission UV–visible spectroscopy.
To assist in the greatly increasing number of applications of Raman microscopy as a tool for non-intrusive, in situ archaeometric analysis, the Raman spectra of over 60 pigments, both natural and synthetic, known to have been in use before approximately 1850 AD, have been studied by Raman microscopy. Fifty-six pigments have yielded high quality spectra which have been arranged, by colour, into a spectroscopic library for reference purposes. The spectroscopic files may be downloaded from http:/(/)www.ucl.ac.uk/chem/resources/raman/speclib .html.
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Non-invasive XRF and UV-VIS-NIR reflectance spectroscopic analysis of materials used by Beato Angelico in the manuscript graduate N8558
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Creation of hyper‐spectral imaging reference database of red lake pigments
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LEDmSF: a new portable device for fragile artworks analyses Applications on medieval pigments An NMR and UV–visible spectroscopic study of the principal colored component of stilde-grain lake
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Daniel F. LEDmSF: a new portable device for fragile artworks
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Non‐invasive XRF and UV‐VIS‐NIR reflectance spectroscopic analysis of materials used by Beato Angelico in the manuscript graduate N°558
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