Pigments—Arsenic-based yellows and reds

Abstract

This review offers an update on arsenic-bearing minerals and pigments with the aim of serving as a guide for the study of Cultural Heritage materials in which these materials can be found.The different As-bearing mineral phases (realgar, pararealgar, orpiment, anorpiment, alacranite, dimorphite, bonazziite, uzonite, wakabayashilite, duranusite, arsenolite and claudetite) and some of their light-induced products are examined. The occurrence of As-sulfides and their trade, use, alteration and degradation are also reviewed. Finally, the analytical techniques commonly used for the identification of arsenic-containing pigments are discussed. The manuscript concludes with a good-practice guide and a summary of key concepts for use by those working in the field of cultural heritage.

Mansfieldite (AlAsO4·2H2O): a new white pigment in Himalayan artwork

“…The air gap between instrument and the hanging thangka prevented the efficient detection of light elements like Al, Si, and S. The dominant As signal did not agree with any of the anticipated white colorants for thangka paintings: Jackson and Jackson list the common whites as kaolin (aluminosilicate), chalk (trigonal CaCO 3 ), gypsum (CaSO 4 •2H 2 O), bone ash (Ca 3 (PO 4 ) 2 ), and later lead white (2PbCO 3 •Pb(OH) 2 ), 1 while aragonite (orthorhombic CaCO 3 from mollusk shells) has been previously identified on one example, 7 and barytes (BaSO 4 ) and titanium dioxide (TiO 2 ) have been documented in modern examples. 8 Arsenic is, however, commonly found in brightly colored artists' pigments including natural yellow orpiment (As 2 S 3 ) and red realgar (α-As 4 S 4 ), 9 as well as synthetic pigments like cobalt violet (Co 3 (AsO 4 ) 2 ) and emerald green (Cu(CH 3 COO) 2 •3Cu(AsO 2 ) 2 ), 10 but not generally in white artists' pigments.…”

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

“…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 (Gliozzo and Burgio 2021); Pb-based whites, reds, yellows and oranges (this paper); 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…”

“…In the first case, the examples are very numerous between the 12 th and 19 th centuries. For example, priming layers constituted of lead white In this regard, the use of lead white for the coating of 17 th to 20 th century Lajian (wax-coated) paper has been investigated by Li et al (2020c); for its use in manuscripts, the reader is referred to Burgio (2021), in this TC.…”

Photoinduced effects of monochromatic visible light with different wavelengths on realgar

“…[ 1–3 ] Meanwhile, due to the degradation of realgar in cultural relics, the most common is a photoinduced reaction of realgar, it loses its original color. [ 4–8 ] In recent years, there have been many studies on the light‐induced transformation of realgar. [ 9–12 ]…”

“…[1][2][3] Meanwhile, due to the degradation of realgar in cultural relics, the most common is a photoinduced reaction of realgar, it loses its original color. [4][5][6][7][8] In recent years, there have been many studies on the light-induced transformation of realgar. [9][10][11][12] It is generally accepted that the light-induced alteration of realgar is from Equations 1-1 to 1-4.…”