A Masterpiece from the Renaissance: The Offiziolo di Durazzo

The manuscript known as Offiziolo di Durazzo, a Book of Hours kept in Genoa at Biblioteca Civica Berio, is among the most notable artistic evidence of the Renaissance. The manuscript was investigated through a fully non-invasive approach involving UV–visible fibre-optic diffuse reflectance spectrophotometry (FORS), X-ray fluorescence spectrometry (XRF), multiband imaging (MBI), and hyperspectral imaging (HSI). The study focused on both the purple parchment and the decorative apparatus, with the aim of improving our understanding of the materials, manufacturing techniques, and state of conservation, while providing scientific evidence to support appropriate conservation strategies, including storage and exhibition conditions. The results of the spectroscopic investigation represent the consistent characterisation of the palette used by the artist Francesco Marmitta, revealing a rich and heterogeneous selection of valuable materials, such as ultramarine blue, vermillion, insect dyes, malachite, gold, and silver. MBI and HSI enabled a spatial investigation of the materials and colour across the manuscript. HSI data were used for both material mapping and colour analysis, revealing subtle spatial heterogeneities associated with the parchment structure, dye distribution, and conservation-related phenomena. HSI data were further exploited to obtain CIELAB colour maps, enabling the assessment of chromatic variability across the manuscript. In decorated areas, the combined interpretation of MBI and HSI spectral mapping allowed the visualisation of the colourant distribution and paint mixtures, providing insights into artistic techniques, material selection, and workshop practices.