Experimental design of the Cu-As-Sn ternary colour diagram. (February 2018)

• Record Type: Journal Article
• Authors: Radivojević, M.; Pendić, J.; Srejić, A.; Korać, M.; Davey, C.; Benzonelli, A.; Martinón-Torres, M.; Jovanović, N.; Kamberović, Ž.
• Is Part Of: Journal of archaeological science. Volume 90(2018)
• Page Start: 106
• Page End: 119
• Publication Date: 2018-02
• Subjects: Colour -- Copper alloys -- Ternary diagram -- Cu-As-Sn alloys -- Colorimetry -- Archaeometallurgy -- Composition -- Voronoi cells -- Tin bronze; Archaeology -- Periodicals; Archéologie -- Périodiques; 930.1
• DOI: 10.1016/j.jas.2017.12.001
• Languages: English
• ISSNs: 0305-4403

Abstract

Abstract: The aesthetic appearance of metals has long been recognised in archaeometric studies as an important factor driving inventions and innovations in the evolution of metal production. Nevertheless, while studies of ancient gold metallurgy are well supported by modern research in colour characteristics of gold alloys, the colour properties of major prehistoric copper alloys, such as arsenical copper and tin bronzes, remain either largely understudied or not easily accessible to the western scholarship. A few published studies have already indicated that alloying and heat treatment change the colours of copper alloys, although they are mainly based on examples of prehistoric tin bronze objects and experimental casts. Here we present a procedure for building the Cu-As-Sn ternary colour diagram, starting with experimental casting of 64 binary and ternary alloys in this system. We used two types of information to produce two different ternary colour diagrams: one based on photographs of the samples, and the other based on the colorimetric measurements. Furthermore, we developed a procedure for creating a graphic representation of colours in the Cu-As-Sn ternary diagram using QGIS. As an initial case study, we plotted the composition of the world's earliest tin bronze artefacts; the graphic representation further supports claims about the importance of a golden hue for their invention and demand, c. 6500 years ago. We argue that the presented colour diagrams will find wide use in future investigations of aesthetics of prehistoric copper alloys. Highlights: Experimentally produced Cu-As-Sn colour diagram to support aesthetics research in archaeometallurgy. Two types of Cu-As-Sn colour diagrams built with high resolution imaging and colorimetry. Case study: early tin bronzes from the Balkans had a distinctive golden hue.