A global approach to the authentication of ancient bronzes based on the characterization of the alloy–patina–environment system

The aim of this paper is to propose a general framework for improving authentication practice of ancient bronze artefacts. In a first part, the article comprehensively reviews the different approaches usually performed to authenticate bronzes, but also evidences their limitations. It is shown that even if numerous technical and fundamental scientific improvements have overcome some of the limitations encountered in the characterization of materials, properties, metal and patina are always considered as independent systems. It is evidenced that authentication requires a global approach based on the investigation of the metallic materials–patina–close environment system. On this basis the complex relationships between alloys, alteration (patinas) and environment (soil…) are successively pointed out, and investigation of the consequence of decuprification (as a global phenomenon of bronze corrosion), taking into account the coupled interactions, is discussed. An application from an example of a fake Chinese ding artefact is then given. A methodological approach is finally proposed, in which many improvements requiring further research could be integrated.