Nobuko Shibayama

Van Gogh’s Irises and Roses : the contribution of chemical analyses and imaging to the assessment of color changes in the red lake pigments

Vincent van Gogh’s still lifes Irises and Roses were investigated to shed light onto the degree to which the paintings had changed, both individually and in relation to each other since they were painted, particularly in regard to the fading of the red lakes. Non-invasive techniques, including macroscopic X-ray fluorescence mapping, reflectance imaging spectroscopy, and X-radiography, were combined with microanalytical techniques in a select number of samples. The in-depth microchemical analysis was necessary to overcome the complications that arise when evaluating by non-invasive methods alone the compositions of passages with complex layering and mixing of paints. The results obtained by these two approaches were complemented by color measurements performed on paint cross-sections and on protected edges, and with historical information provided by the artist’s own descriptions, early reviews and reproductions, and the data was used to carry out digital color simulations that provided, to a certain extent, a visualization of how the paintings may have originally appeared.Graphical abstractIrises, 1890, Vincent van Gogh. The Metropolitan Museum of Art #58.187. Zn (upper right), Pb (bottom left), and Br (bottom right) distribution maps acquired by XRF imaging.

A multi-analytical approach for the identification of aloe as a colorant in oil–resin varnishes

Aloe plants have been widely documented in artists’ treatises dating from the sixteenth to the nineteenth century as a source of colorant to achieve lustrous golden glazes on tin- and silver-foiled objects and warm-toned finishes on musical instruments, such as violins. Aloe extracts contain characteristic anthraquinone and phenolic components which impart a distinctive orange tone and fluorescence to mixtures containing them. Because of the low concentration of colorant in the coatings and its probable degradation by high temperature during manufacture, the identification of aloe in heated oil–resin mixtures represents an analytical challenge. For this reason, the possible presence of aloe in glazes and coatings has been largely overlooked. This paper describes various analytical approaches to the identification of aloe in historic samples, from comparison with results obtained from reference standards and mock-up samples. Complementary analytical techniques including thermally assisted hydrolysis and methylation–gas chromatography–mass spectrometry, high-performance liquid chromatography, laser desorption–mass spectrometry, matrix-assisted laser desorption-ionization-mass spectrometry and surface-enhanced Raman scattering were used. Different chemical markers were identified by the individual methods and the advantages and limitations of each technique for the identification of aloe in oil–resin varnishes are discussed.

Analysis of natural dyes and metal threads used in 16 th -18 th century Persian/Safavid and Indian/Mughal velvets by HPLC-PDA and SEM-EDS to investigate the system to differentiate velvets of these two cultures

IntroductionAnalyses of natural dyes and the metal of the metal-wrapping threads used in 16th -18th century Persian/Safavid and Indian/Mughal period velvets were performed on these textiles in the collection of The Metropolitan Museum of Art. The purpose was to determine whether velvets from the two cultures, which have shown problems in the past with attribution based on historical and iconographical studies, could be more precisely differentiated with the additional evidence from identification of their natural dyes and metals along with information of weaving techniques.Dyes and metal of the metal-wrapped threads from fifteen Persian velvets and six Indian velvets were analyzed by high performance liquid chromatography with photo diode array detector and by scanning electron microscopy with energy dispersive X-ray spectrometry respectively.ResultsThere seem to be types of dyes which specifically characterize the velvets of each culture, as well as types of dyes commonly found in velvets of both cultures. Dyes typical of Persian velvets are cochineal and yellow larkspur, while lac and turmeric are characteristic of Indian velvets. The dyes commonly found are a combination of yellow larkspur and indigo dye in green, as well as safflower, indigo dye, soluble redwoods, and tannin dye. There were exceptions however. Because of those exceptions, examining the range of dyes used in the velvets would be important in differentiating the velvets. Metal used for wrapping the threads was in all cases found to be silver of fairly high purity, the majority of which had been gilded. The silver from Persia metal threads showed very slightly higher copper content, while Indian threads showed nearly pure silver. This is the first extensive comparative study of dyes and metal threads of Safavid and Mughal velvets: the first evidence of yellow larkspur being the most used yellow dye in Persia, and of the possible differences in the two cultures’ metal threads.ConclusionIn addition to knowledge gathered from investigation of weave structure and from historical and iconographic studies, analysis of dyes and metal threads will contribute to a clearer differentiation of those two cultural groups of textiles.

Pigments in a Paint Box Belonging to Whistler in the Library of Congress

Abstract A paint box and palette that belonged to the American painter James McNeill Whistler(1834-1903) are in the Library of Congress, Washington, DC. There are 37 tubes of paint in the box, including 6 in a separate cardboard box labeled Spectrum Colors. There are also painting and etching tools. The tubes were supplied by five British colormen except for the Spectrum Colors, which came from the American firm of Devoe & Raynolds Inc. Some of the tube labels are missing or illegible. The pigments were identified using polarized light microscopy, X-ray powder diffraction, high performance liquid chromatography, and Raman spectroscopy. Information from Devoe & Raynolds catalogs suggests that the Spectrum Colors were not available before 1909; toluidine red, found in one Spectrum Color, was first synthesized in1904. Thus, the Spectrum Colors must have been put in the paint box after Whistlers death. Of the other pigments in the box, three – graphite, emerald green and synthetic malachite – are not known to have been used by him, but it may be that they are yet to be identified. The paint box was given to the Library of Congress by Joseph and Elizabeth Pennell in 1917, 14 years after the artists death, and it is not known whether the paint box was used during that time.

Redeeming Pieter Coecke van Aelst’s Gluttony Tapestry: Learning from Scientific Analysis

Pieter Coecke van Aelst (1502 – 1550) was one of the most celebrated Netherlandish artists of his generation.1 An important panel painter and printer of influential architectural treatises, Coecke was above all a master draftsman-designer, and the primary medium for his artistic expression was tapestry design. Tapestry series based on his cartoons were woven up by the celebrated Brussels-based workshops directed by Willem de Pannemaker and Willem de Kempeneer, as well as lesser-known weavers like Jan van der Vijst and Paulus van Oppenem, and were acquired by the great Renaissance collectors, from Henry VIII to Francis I, Mary of Hungary, Charles V, and Cosimo I de’ Medici. The three securely documented tapestry series that form the core of Pieter Coecke van Aelst’s stylistically attributed body of works are the Life of Saint Paul, the Seven Deadly Sins, and the Story of Joshua.2 These were all phenomenally successful and woven in multiple high-quality editions. The Seven Deadly Sins, in particular, is one of the most appealing and inventive series of Renaissance tapestries known, presenting a subversive triumphal procession of the vices across seven tapestries, each devoted to a different sin. Uniquely for tapestries of this period, a written program survives in a manuscript in Madrid, describing the “significance of the seven tapestries of the seven deadly sins by Willem de Pannemaker of which master Pieter of Aelst, painter of Antwerp, made the designs and compositions.”3 Coecke probably began designing the Sins in late 1532, pausing during 1533, when he traveled to Constantinople (in part on a tapestry-selling expedition to Süleyman the Magnificent), completing the design of the series after his return in early 1534. Of the earliest documented edition, woven before 1536, which belonged to Henry VIII, only Avarice survives; it is now in the Morgan Library and Museum in New York.4 Of the three best-preserved Seven Deadly Sins editions, one (Figure 1) originally belonged to Mary of Hungary (1505 – 1558), governor of the Habsburg Netherlands (1531 – 55). Made before 1544, it is now in the Spanish Patrimonio Nacional. Another (Figure 2), made about 1545, was first acquired by the unfortunate Count Lamoraal van Egmont, prince of Gavere (1522 – 1568). Follow ing Egmont’s execution, it passed to Philip II and is now also in the Patrimonio Nacional. The third, woven about 1548 – 49 and probably originally in the collection of the dukes of Lorraine, is now in the Kunsthistorisches Museum in Vienna.5 Since 1957, The Metropolitan Museum of Art has owned one piece of the Seven Deadly Sins that Coecke designed; it represents Gluttony and is the only known survival from this, the fifth known edition (Figure 3).6 In a breathtakingly colorful sweep of twisting figures, fantastical beasts, and patterned cloth and trappings, the figures unfurl across the tapestry’s surface.7 The textile’s well-preserved, vivid palette enlivens the full subtleties of Coecke’s design. Owing to the Redeeming Pieter Coecke van Aelst’s Gluttony Tapestry: Learning from Scientific Analysis