Unusual pigments found in a painting by Giotto (c. 1266-1337) reveal diversity of materials used by medieval artists

Abstract

Background:The important trecento Florentine artist Giotto (c. 1266Giotto (c. -1337 is renowned for his naturalistic and realistic works in tempera and fresco. His innovative paintng style involved painting expressive, emotive faces and use of pictorial devices for depicting space. This report focuses on the analysis of the materials and methods used in a panel in the collection of the National Gallery of Art, Madonna and Child (1310/1315).Results: Giotto used inky washes under thin layers of egg tempera paint. Yellow iron earth and lead tin yellow are present in the paint used to depict the lining of the Virgin's mantle. SEM-EDX of one of the yellow pigments confirmed it is lead tin yellow type II, PbSn 1-x Si x O 3 . The ratio of colorant to the glassy phase indicates this material was produced for use as a pigment rather than as a glass. Ultramarine was not used in this painting, azurite is the blue pigment. The azurite used here does not contain elemental impurities, however malachite and the rare green-blue mineral mixite, BiCu 6 (OH) 6 (AsO 4 ) 3 (H 2 O) 3 , are found in the blue paint.

European ceramic technology in the Far East: enamels and pigments in Japanese art from the 16th to the 20th century and their reverse influence on China

“…9) [4]: the composition of the green enamel analyzed on the shard perfectly matches the green pigment detected on the early-seventieth-century screen Western Kings on horseback [55]. In terms of technological implications, an early use of a Cu-As-Zn based green pigment has been clearly detected on the works by the sixteenth-century Italian painter Stefano Sparano [56]. Once again, the practice of using the same materials for paintings and ceramics is of European origin and does not belong to Japanese tradition.…”

Characterisation of the different hands in the composition of a 14th century breviary by means of portable XRF analysis and complementary techniques

“…There is, however, an interesting additional feature in the analysis of blue initials: the systematic presence of bismuth at trace level amounts (<0.1%). This element has been recently highlighted in the analysis of a painting by Giotto in which the blue areas resulted to be composed by azurite with impurities of malachite and mixite , a rare green‐blue mineral with formula BiCu 6 (OH) 6 (AsO 4 ) 3 ·3H 2 O. Despite in situ XRF analysis could not give an absolutely reliable identification of this mineral phase, the contextual presence of Cu and Bi strongly suggests that mixite is accompanying azurite in the blue initials of the Breviario ; in fact, a linear correlation between the two elements can be demonstrated on the base of XRF data (Fig.…”

Paint Relics on Middle Age Building Stones as Proxies of Commercial Routes and Artistic Exchanges: A Multi-Analytical Investigation

“…Antique treatises report that copper carbonate was extracted mainly in Hungary and Germany, and in Chessy (near Lyon, France), Sardinia, and Tuscany (near Siena, Italy) [5,[26][27][28]. The occurrence of accessory monazite and clinoatacamite, malachite, barite, and mixite, associated with azurite in the addressed paint layers were used to infer a plausible pigment provenance [29,30]. The associated atacamite and clinoatacamite can be interpreted as intentional additions to the mixture, accessory minerals proxies of the ore deposit, or weathering product [31].…”

“…Also, the rare grains of malachite associated with azurite in natural outcrops and originating as its natural decay product in wet environments, could be naturally associated to calcite or intentionally added to obtain a desired color. Mixite has already been found in Italian artworks as impurity associated with azurite [28,30] and hypothesized as a provenance indicator [30]. By joining the historical data of the coeval technical essays, and its occurrence with azurite, the possible provenance for the pigment was restricted to Germany, Hungary, and, probably, the Czech Republic [30,32].…”

“…Mixite has already been found in Italian artworks as impurity associated with azurite [28,30] and hypothesized as a provenance indicator [30]. By joining the historical data of the coeval technical essays, and its occurrence with azurite, the possible provenance for the pigment was restricted to Germany, Hungary, and, probably, the Czech Republic [30,32]. Moreover, the presence of monazite grains, a ubiquitous mineral phase, and pyromorphite could provide provenance indications, although no literature is reported.…”