Non‑invasive contactless analysis
of an early drawing by Raffaello
Sanzio by means of optical
Authors: Quintero Balbas D., Dal Fovo A., Monalbano L., Fontana R., Striova J.
Autors Affiliation: National Research Council—National Institute of Optics (CNR-INO), L.go E. Fermi 6, 50125 Florence,
Laboratorio di Restauro Cartacei e Membranacei, Opificio delle Pietre Dure-MiC, Viale F. Strozzi 1, 50129 Florence, Italy.
Abstract: Studying highly valuable and fragile Renaissance drawings requires a non-invasive contactless
analytical approach. In this work, we study an early drawing by Raffaello Sanzio, one of the most
important artists of the Italian Renaissance, realized during his stay in Florence (1504–1508). Our
analyses aimed to reveal the features of the paper support significant for its dating, identify and
map the drawing media to understand the artist’s technical approach, and document the drawing
condition with imaging and single-sited optical methods. Reflectance Vis–NIR multispectral imaging
spectroscopy elaborated with False-Colour and Principal Component Analysis provided information
about the paper support and the drawing media. Laser scanning micro-profilometry and Optical
Coherence Tomography allowed revealing the superficial micro-scale features of the support. The
chemical composition of the different drawing materials was characterized by μ-Raman spectroscopy,
which provided also some evidence of the conservation history of the drawing. Integration of
spectroscopic and imaging data shows that Raffaello used different dry drawing media (carbon-based
and Pb stylus) to sketch the figure and then refined the details and shadows with iron-gall ink. The
paper presents a methodological approach for the analytical examination of fragile paper artworks.
Journal/Review: SCIENTIFIC REPORTS
Volume: 12 Pages from: 1 to: 10
KeyWords: drawing, Raffaello, PCA, Raman spectroscopy, multispectral reflectography, microprofilometry, OCTDOI: https://doi.org/10.1038/s41598-022-18600-2