A study of the origin and gilding technique of a Hispano-Philippine ivory from the XVIIth century

Scanning electron microscopy was used to determine the materials and gilding techniques used in this type of sculpture. This is a new aspect for Hispano-Philippine ivories, but a recurrent one for medieval ivories. The results obtained in this study allow us to present the gilding technique used to decorate the Immaculate Conception image as a water gilding (“guazzo”) over an oil/mordant gilding. Water gilding uses a layer of gesso and a layer of bole to make the gold leaf adhere, and was traditionally used for wood surfaces, but has also been documented in the cases of some medieval ivory sculptures.