Pigments—Lead-based whites, reds, yellows and oranges and their alteration phases

This review summarises the state-of-the-art of lead-based pigment studies, addressing their production, trade, use and possible alteration. Other issues, such as those related to the investigation and protection of artworks bearing lead-based pigments are also presented. The focus is mineralogical, as both raw materials and degradation products are mineral phases occurring in nature (except for very few cases). The minerals described are abellaite, anglesite, blixite, caledonite, challacolloite, cerussite, cotunnite, crocoite, galena, grootfonteinite, hydrocerussite, laurionite, leadhillite, litharge, macphersonite, massicot, mimetite, minium, palmierite, phosgenite, plattnerite, plumbonacrite, schulténite, scrutinyite, somersetite, susannite, vanadinite and an unnamed phase (PbMg(CO3)2). The pigments discussed are lead white, red lead, litharge, massicot, lead-tin yellow, lead-tin-antimony yellow, lead-chromate yellow and Naples yellow. An attempt is made to describe the history, technology and alteration of these pigments in the most complete manner possible, despite the topic's evident breadth. Finally, an insight into the analytical methods that can (and should) be used for accurate archaeometric investigations and a summary of key concepts conclude this review, along with a further list of references for use as a starting point for further research.

Restoration of the silhouette “Emperor Nicholas I and the Cadet Bubnov”

В статье представлено описание реставрации силуэта «Император Николай I и кадет Бубнов», переданного наряду с другими силуэтами в лабораторию научной реставрации графики из отдела истории русской культуры Государственного Эрмитажа. Композиция предмета состоит из бумажного силуэта в рамке золотого цвета, наклеенного на черный глянцевый фон, бумажную и картонную подложки. Данный силуэт передан в реставрацию из-за повреждений, имеющих тенденцию к развитию и неблагоприятных как для состояния сохранности бумаги-основы, так и для красочных слоев. Исследования бумаги позволили выявить визуально незаметный слой свинцовых белил на поверхности силуэта. В процессе реставрации была открыта исторически значимая надпись «Подарок Мейбаумъ 4. 28 августа 1835». Мы можем предположить, что надпись указывает на автора силуэта, воспитанника Первого кадетского корпуса Мейбаума, либо на его родственника, подарившего силуэт. С каждым элементом предмета проведены реставрационные мероприятия. Основная часть работ выполнена над бумажным силуэтом, имеющим не только пятна, но и разрывы вследствие деформации бумажной основы и картона. Особенностями оформления композиции после реставрации является инкапсулирование силуэта в полиэфирную пленку, предотвращающую взаимодействие свинцовых белил с воздухом, и крепление всех элементов конструкции по верхнему краю. После реставрации сохранен авторский замысел: инкапсулированный силуэт на черном глянцевом фоне, окаймленный рамкой золотого цвета, крепится к бумажной подложке. The article presents a description of the restoration of the silhouette “Emperor Nicholas I and the Cadet Bubnov” which was transferred along with other silhouettes to the Laboratory for Scientific Restoration of Graphics from the Department of the History of Russian Culture of the State Hermitage Museum. The composition of the subject consists of a paper silhouette in a gold frame, pasted on a glossy black background, paper and cardboard backings. This silhouette was handed over for restoration due to damages that tended to develop and were unfavorable both for the state of preservation of the base paper and for the paint layers. The paper studies made it possible to reveal a visually imperceptible layer of lead white on the silhouette surface. During the restoration process, the historically significant inscription “Gift of Meibaum 4. August 28, 1835” was discovered. We can assume that the inscription points to the author of the silhouette, a student Meibaum studied in the First Cadet Corps, or to his relative who donated the silhouette. Restoration procedures have been carried out with each element of the object. The main part of the work has been done on a paper silhouette, which had not only spots, but also tears due to the deformation of the paper support and cardboard. The features of the composition design after restoration are the encapsulation of the silhouette in a polyester film, which prevents the interaction of lead white with air, and the fastening all structural elements along the upper edge. After the restoration the author's idea has been kept: the encapsulated silhouette on a black glossy background, bordered by the golden frame, is attached to a paper backing.

Complex Relationships: A Materials Study of Édouard Vuillard’s Interior, Mother and Sister of the Artist

Édouard Vuillard (1868–1949) is well known for his small atmospheric paintings, often portraying his own home and family as the subject matter. Interior, Mother and Sister of the Artist (1893) underwent at least one restoration treatment before being acquired by the Museum of Modern Art (MoMA) in 1934. The painting was treated again in 1954, but no analysis was carried out to understand the artist’s methods and materials at that time. To better understand the choices of Vuillard in Interior, Mother and Sister of the Artist, a comprehensive suite of imaging and spectroscopic analyses was undertaken, including: XRR, UVF and IRR Photography, XRF, Raman spectroscopy and SERS, and µ-FTIR. Statistical analysis on the XRF data using MCR-ALS further revealed some of the intricacies of Vuillard’s technique and color choices, where a large number of pigments were used in designing this intimate composition, including lead white, zinc white, bone black, ochre, umber, vermilion, Geranium lake, red lead, ultramarine, Prussian blue, chrome yellow, chrome orange, zinc yellow, strontium yellow, cadmium yellow, and a chromium oxide green.

Identification of Colourants and Varnishes in a 14th Century Decorated Wood-Carved Door of the Dionysiou Monastery in Mount Athos

A decorated and carved wooden door of the late Byzantine period (14th Century), which belongs to the Dionysiou Monastery in Mount Athos, Greece, constitutes an important relic of valuable technological information due to its construction technology and history. Seventeen (17) samples detached from the door are studied using optical microscopy, scanning electron microscopy (SEM) with energy dispersive X-ray analysis (SEM-EDX), and micro-Raman and FTIR spectroscopy. The following materials are identified in the cross sections of the door samples using micro-Raman spectroscopy: orpiment, lead white, red lead, red ochre, cinnabar, carbon black, gypsum, anhydrite, and calcite, and an organic colourant of the indigoid family. SEM-EDX studies supported to the aforementioned Raman results. Interestingly, a combination of inorganic and organic colourants was detected. The main goals of this particular study were to: (a) reveal the colour palette and materials, (b) identify the type of varnish and its condition, and (c) contribute to future restoration processes and aid conservators in selecting compatible restoration materials.

“If You Don’t Speak English, I Can’t Understand You!”: Exposure to Various Foreign Languages as a Threat

The number of non-English speaking and bilingual immigrants continues to grow in the U.S. Previous research suggests that about one third of White Americans feel threatened upon hearing a language other than English. The current research examines how exposure to a foreign language affects White Americans’ perceptions of immigrants and group-based threats. In Study 1, White Americans were randomly assigned to read one of four fictional transcripts of a conversation of an immigrant family at a restaurant, where the type of language being spoken was manipulated to be either Korean, Spanish, German, or English. In Study 2, White Americans read the same fictional transcript—minus the Spanish; however, there was an addition of two subtitles conditions in which the subtitles were provided next to the Korean and German texts. The two studies suggest that exposure to a foreign language—regardless of whether they are consistent with Anglocentric constructions of American identity—lead White Americans to form less positive impressions of the immigrant targets and their conversation, experience an uptick in group-based threats, and display greater anti-immigrant attitudes. Moreover, there is evidence that the (in)ability to understand the conversation (i.e., epistemic threat) influences participants’ perceptions of immigrants and group-based threats.

Revealing Artists’ Collaboration in a 14th Century Manuscript by Non-Invasive Analyses

In the last decades, the working methods of late medieval illuminators have been widely discussed by art historians and codicologists. Non-invasive analyses are able to characterise the painting methods of illuminators as well as investigate artistic collaborations among them. The aim of this study was to characterise the painting palettes and techniques of different artists who illuminated two leaves from an early fourteenth century manuscript. The analyses were carried out with non-invasive and portable techniques such as Energy Dispersive X-ray Fluorescence (ED-XRF) spectrometry, Fiber Optics Reflectance Spectroscopy (FORS) and Raman spectroscopy. The paper highlights the differences among three rich and varied palettes and examines the pigments ultramarine, azurite, verdigris, earths, orpiment, red lead, vermillion, lead white, yellow lake, indigo, brazilwood and lac, used independently or in mixtures. We have demonstrated the effectiveness of non-invasive analyses as a tool to differentiate hands of artists who have worked on the same page. Furthermore, the comparison with analyses carried out on leaves attributed to the workshop of Pacino di Bonaguida allows to investigate in-depth the production of the main illuminators active in Florence at the dawn of the Renaissance.

Radiocarbon dating of lead white: novel application in the study of polychrome sculpture

Recently, radiocarbon dating underwent considerable technological advances allowing unprecedented sample size downscaling. These achievements introduced novel opportunities in dating cultural heritage objects. Within this pioneering research, the possibility of a direct 14C dating of lead white pigment and organic binder in paint samples was investigated on polychrome sculptures, a foremost artistic expression in human history. The polychromy, an indivisible part of polychrome sculpture, holds a key role in the interpretation and understanding of these artworks. Unlike in other painted artworks, the study of polychromies is repeatedly hampered by repaints and degradation. The omnipresence of lead white within the original polychromy was thus pursued as dating proxy. Thermal decomposition allowed bypassing geologic carbonate interferences caused by the object's support material, while an added solvent extraction successfully removed conservation products. This radiocarbon dating survey of the polychromy from 16 Portuguese medieval limestone sculptures confirmed that some were produced within the proposed chronologies while others were revised. Within this multidisciplinary study, the potential of radiocarbon dating as a complementary source of information about these complex paint systems guiding their interpretation is demonstrated. The challenges of this innovative approach are highlighted and improvements on sampling and sample preparation are discussed.

Exploring Liu Kang’s Paris Practice (1929–1932): Insight into Painting Materials and Technique

This paper presents the results of an extensive study of 14 paintings by the pioneering Singapore artist Liu Kang (1911–2004). The paintings are from the National Gallery Singapore and Liu family collections. The aim of the study is to elucidate the painting technique and materials from the artist’s early oeuvre, Paris, spanning the period from 1929 to 1932. The artworks were studied with a wide array of non- and micro-invasive analytical techniques, supplemented with the historical information derived from the Liu family archives and contemporary colourmen catalogues. The results showed that the artist was able to create compositions with a limited colour palette and had a preferential use of commercially available ultramarine, viridian, chrome yellow, iron oxides, organic reds, lead white, and bone black bound in oil that was highlighted. This study identified other minor pigments that appeared as hue modifications or were used sporadically, such as cobalt blue, Prussian blue, emerald green, cadmium yellow, cobalt yellow, and zinc white. With regard to the painting technique, the artist explored different styles and demonstrated a continuous development of his brushwork and was undoubtedly influenced by Modernists’ artworks. This comprehensive technical study of Liu Kang’s paintings from the Paris phase may assist art historians and conservators in the evaluation of the artist’s early career and aid conservation diagnostics and treatment of his artworks. Furthermore, the identified painting materials can be compared with those used by other artists active in Paris during the same period.