Gilded wood is an important part of Portuguese cultural heritage. We profit an intervention in the organ of the Church of Santa Cruz (Coimbra) to make a study on its gilded wood decoration. Historical sources indicate that the organ dates from the XV-XVI centuries, although it has suffered several restoration works over the centuries. Samples were collected from different places of the central part of the organ. Scanning electron microscopy combined with energy dispersive X-ray spectroscopy, optical microscopy, X-ray diffraction and Fourier transform infrared spectroscopy were the techniques used in this work to analyze the samples. Stratigraphical sequence and global chemical and mineralogical analysis data allowed the identification of the gilding techniques. All the samples exhibit the typical technique brought by Portuguese artists from China, with kaolin in the bolus composition. Some samples present a typical Italian and Flemish technique developed in the XIV century, and used in the XVII century, with gypsum (gesso mate and gesso grosso) in the preparation layer.
gilded wood; optical microscopy; scanning electron microscopy and energy dispersive X-ray spectroscopy; X-ray diffraction; Fourier transform infrared spectroscopy
