applying-hyperspectral-reflectance-imaging-to-investigate-palettes

Applying Hyperspectral Reflectance Imaging to Investigate the Palettes and the Techniques of Painters

Reflectance Spectroscopy (RS) and Fiber Optics Reflectance Spectroscopy (FORS) are well-established techniques for the investigation of works of art with ...

Università degli Studi di Milano-Bicocca

CNR-IBFM

Non-invasive, portable analytical techniques are becoming increasingly widespread for the study and conservation in the field of cultural heritage, proving that a good data handling, supported by a deep knowledge of the techniques themselves, and the right synergy can give surprisingly substantial results when using portable but reliable instrumentation. In this work, pigment characterization was carried out on 21 Leonardesque paintings applying in situ X-ray fluorescence (XRF) and fiber optic reflection spectroscopy (FORS) analyses. In-depth data evaluation allowed to get information on the color palette and the painting technique of the different artists and workshops . Particular attention was paid to green pigments (for which a deeper study of possible pigments and alterations was performed with FORS analyses), flesh tones (for which a comparison with available data from cross-sections was made), and ground preparation.

Looking for Common Fingerprints in Leonardo's Pupils Using Nondestructive Pigment Characterization.

Uncovering the underdrawings (UDs), the preliminary sketch made by the painter on the grounded preparatory support, is a keystone for understanding the painting's history including the original project of the artist, the  (an underlying image in a painting providing evidence of revision by the artist) or the possible presence of co-workers' contributions. The application of infrared reflectography (IRR) has made the dream of discovering the UDs come true: since its introduction, there has been a growing interest in the technology, which therefore has evolved leading to advanced instruments. Most of the literature either report on the technological advances in IRR devices or present case studies, but a straightforward method to improve the visibility of the UDs has not been presented yet. Most of the data handling methods are devoted to a specific painting or they are not user-friendly enough to be applied by non-specialized users, hampering, thus, their widespread application in areas other than the scientific one, e.g., in the art history field. We developed a computer-assisted method, based on principal component analysis (PCA) and image processing, to enhance the visibility of UDs and to support the art-historians and curators' work. Based on ImageJ/Fiji, one of the most widespread image analysis software, the algorithm is very easy to use and, in principle, can be applied to any multi- or hyper-spectral image data set. In the present paper, after describing the method, we accurately present the extraction of the UD for the panel "The Holy Family with St. Anne and the Young St. John" and for other four paintings by Luini and his workshop paying particular attention to the painting known as "The Child with the Lamb".

Behind the Scene of "The Holy Family with St. Anne and the Young St. John" by Bernardino Luini: A Computer-Assisted Method to Unveil the Underdrawings.

Anna Galli

Dipartimento di Scienza dei Materiali

Università degli Studi di Milano-Bicocca

Applying Hyperspectral Reflectance Imaging to Investigate the Palettes and the Techniques of Painters

Anna Galli

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Dipartimento di Scienza dei Materiali

Università degli Studi di Milano-Bicocca

Applying Hyperspectral Reflectance Imaging to Investigate the Palettes and the Techniques of Painters

Dipartimento di Scienza dei Materiali