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

Abstract

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.

Pigments—Arsenic-based yellows and reds

“…Three archaeological reviews on prehistoric (Domingo Sanz and Chieli 2021), Roman (Salvadori and Sbrolli 2021) and Medieval (Murat 2021) wall paintings clarify the archaeological and historical/cultural framework. A series of archaeometric reviews illustrate the state of the art of the studies carried out on Fe-based red, yellow and brown ochres (Mastrotheodoros et al 2021), Cu-based greens and blues (Švarcová et al 2021), As-based yellows and reds (this paper), Pb-based whites, reds, yellows and oranges (Gliozzo and Ionescu 2021), Hg-based red and white (Gliozzo 2021) and organic pigments (Aceto 2021). An overview of the use of inks, pigments and dyes in manuscripts, their scientific examination and analysis protocol (Burgio 2021) as well as an overview of glass-based pigments (Cavallo and Riccardi 2021) are also presented.…”

“…Their studies-chiefly performed by means of synchrotron radiation X-ray micro-analyses (As-K edge micro-X-ray absorption near edge structure)-also helped hypothesizing a 5-step process for arsenic trioxide: (1) formation; (2) dissolution in water, (3) oxidation to arsenic pentaoxide, (4) the reaction with other ions (e.g., Pb and Ca) and, finally, (5) deposition as insoluble arsenate. Vanmeert et al (2019) found mimetite and schulténite as decay products of realgar and orpiment (for lead-based pigments see Gliozzo and Ionescu 2021). Similarly, Hradil et al (2014) found mimetite as the alteration product of orpiment and minium.…”

Ancient Restoration in Roman Polychromy: Detecting Aesthetic Changes?

“…However, the detection of lead, lead colocalised with iron, an White is used as a preparation layer for the final chromatic application on the altar of Apollo, on the Lycian Apollo (Figure 19a), and on the warrior leg. In the first two cases, it appears yellowish: the lead signal suggests the use of lead white, commonly attested in wall painting and in statuary during the Roman period [27]. On the warrior leg, the presence of sulphur and calcium suggest the use of stucco as a preparatory layer [18].…”

“…The significant amount of lead and iron is observed in the yellow, and the brown of the most superficial layer is visible in the altar of Apollo and the two torsos. The association of these two elements suggests the use of lead mixed with ochres, or the use of sandyx (Pliny, Naturalis Historia, 35, 30, 40) [27,29]. The colocalization of iron and lead is observed by mapping: the distribution of these elements corresponds to the areas where colour was applied (Figure 19b).…”

Multi-technique analysis of pigments on sandstone sculptures: Renaissance re-painting of a Roman relief

“…The presence of lead sulphate as a ground layer is reported as rare and is usually thought to be due to degradation of other pigments and a comprehensive review has found it to be present in a number of works crossing the prehistoric to Medieval periods [27]. It was identified in a study of the Room of the Beds in the Royal Bath of Comares of the Alhambra monument in the Iberian peninsula redecorated during the Renaissance period and the intentional presence of lead sulphate cannot be fully disregarded [28].…”