Chemical characterization and origin of dyes used in the manufacture of Beninese cultural heritage objects

• Published in: Color research and application Vol. 44; no. 2; pp. 234 - 242
• Main Authors: Fagbohoun, Louis, Mathe, Carole, Gbaguidi, Fernand A., Ayedoun, Marc A., Moudachirou, Mansourou, Vieillescazes, Cathy
• Format: Journal Article
• Language: English
• Published: Hoboken, USA John Wiley & Sons, Inc 01.04.2019; Wiley Subscription Services, Inc; Wiley
• Subjects: Analytical chemistry; chemical characterization; Chemical Sciences; colored materials; conservation; Cultural heritage; cultural heritage objects; Cultural resources; Dyes; Fourier transforms; Indigo; Iron oxides; Liquid chromatography; museum collections; Museums; Organic chemistry; Organic compounds; Photodiodes; Pigments; Restoration; conservation; museum collections; chemical characterization; colored materials; liquid chromatography; cultural heritage objects; restoration
• ISSN: 0361-2317; 1520-6378
• DOI: 10.1002/col.22325

Six objects of Beninese cultural heritage provided by African and Confluences museums of Lyon (France) were the focus of this study. The characterization of colored compounds was achieved using: microchemical tests, Fourier transform infrared spectroscopy and liquid chromatography coupled to a photodiode array detector. The main results reflect the presence of organic compounds like indigotin, 2‐hydroxynaphthoquinone, and mineral ions such as Al3+, S2−, Na+, and Fe3+. Dyes were identified from Philenoptera cyanescens (Yoruba indigo) and Lawsonia inermis L. (henna); pigments were identified as laundry blue, Prussian blue, and iron oxides. All of these data therefore make possible the conservation and the restoration of these objects while maintaining their visual and functional integrity.