Traces of former restorations of Raphael’s La Muta as seen by Optical Coherence Tomography

A preprint of the article published in "Raffaello, La Muta Indagini e restauro", edited by M. Ciatti and M.R Valazzi (Edifir, Firenze, 2015), pp. 117-119

Chapter OCT for Examination of Cultural Heritage Objects

Optical coherence tomography (OCT) was first time reported as a tool for examination of cultural heritage objects in 2004. It is mainly used for the examination of subsurface structure of easel paintings (such as varnishes and glazes) and has also been successfully used for inspection of other types of artworks, provided that they contain layers that are permeable to the probing light. This chapter discusses the last applications of OCT in this area with an emphasis on synergy with some other noninvasive techniques such as large-scale X-ray fluorescence (XRF) scanning and reflective Fourier transform infrared (FTIR) spectroscopy. After this part, there is a detailed description of the high-resolution OCT instrument developed by the authors specifically for the study of works of art. Next, two examples are given for the structural examination of works of art: in the former, the subsurface layers of an easel painting are presented, and in the latter, the painting on reverse of the glass is examined, when the inspection must be carried out through the glass. Finally, an application for the assessment of chemical varnish removal from an easel panel painting is discussed in details

OCT for examination of cultural heritage objects

a chapter preprint to the book “Optical Coherence Tomography and Its Non-medical Applications” Michael Wang ed., IntechOpen 2019OCT was first time reported as a tool for examination of cultural heritage objects in 2004. It is mainly used for examination of subsurface structure of easel paintings (such as varnishes and glazes) but has also been successfully used for inspection of other types of artworks, provided that they contain layers that are permeable to the probing light. This chapter discusses the last applications of OCT in this area with an emphasis on synergy with some other non-invasive techniques such as large scale X-ray fluorescence (XRF) scanning and reflective Fourier transform infrared (FTIR) spectroscopy. After this part, there is a detailed description of the high resolution OCT instrument developed by authors specifically for the study of works of art. Next, two examples are given for the structural examination of works of art: in the former the sub-surface layers of an easel painting are presented, in the latter the painting on reverse of the glass is examined, when the inspection must be carried out through the glass. Finally, an application for the assessment of chemical varnish removal from an easel panel painting is discussed in details

Optical Coherence Tomography (OCT) for examination of artworks

Chapter in the book: Bastidas D., Cano E. (eds) Advanced Characterization Techniques, Diagnostic Tools and Evaluation Methods in Heritage Science. Springer, Cham, 2018, pp 49-59 , doi: 10.1007/978-3-319-75316-4, Authors’version after embargo periodOptical coherence tomography is a fast, non-invasive technique of structural analysis utilising near-infrared radiation. Examples of using OCT, for obtaining cross-sectional images of objects of craftsmanship and an easel painting have been shown. Issues regarding the technique of execution and destruction phenomena were resolved non-invasively. In some cases, the secondary alterations can be identified and localised within the object’s structure which helps in authentication of the artwork

Using Optical Coherence Tomography to Reveal the Hidden History of The Landsdowne Virgin of the Yarnwinder by Leonardo da Vinci and Studio

Optical Coherence Tomography (OCT) was used for non-invasive examination of a well-known, yet complex, painting from the studio of Leonardo da Vinci in combination with routine imaging in various bands of electromagnetic radiation. In contrast with these techniques, OCT provides depth-resolved information. Three post-processing modalities were explored: cross-sectional views, maps of scattering from given depths, and their 3D models. Some hidden alterations of the painting due to past restorations were traced: retouching and overpainting with their positioning within varnish layers as well as indications of a former transfer to canvas

On the application of Optical Coherence Tomography as a complimentary tool in an analysis of the 13th century Byzantine Bessarion Reliquary

Accepted version (after embargo period)This work presents the results of an application of optical coherence tomography (OCT) to examine a 13th century Byzantine reliquary of unparalleled artistic and historical value. The aim of this work, performed at the initial stage, before the restoration, was focused on the resolution of cleaning procedures regarding both the thick, old varnish and the gold leaf details finely applied on the painted parts of the artwork by means of an integrated approach of non-invasive and invasive analyses and diagnostics. The results allow definition of the thickness of the varnishes, their inner morphology and establishes the presence (or absence) of secondary layers of gold leaf upon the original ones. Knowledge of varnish thickness and in-depth localisation of the secondary gold leaf allowed the restoration procedure of cleaning and thinning of the altered varnish to be performed safely and effectively in order to recover the wonderful pristine sight of a precious and ancient byzantine work of art

Non-invasive survey of pre-restoration condition of the ceiling paintings by Peter Paul Rubens at the Banqueting House Whitehall, London, by means of Optical Coherence Tomography

A preprint of the article submitted to Studies in Conservation on November 30, 2018 as a contribution to LACONA 12 conference special issue.This article presents the results of the examination by means of optical coherence tomography (OCT) of two of the nine monumental ceiling paintings by Peter Paul Rubens and his studio, still located in their original location at the Banqueting House, the only surviving building of the former Whitehall Palace in London. OCT is a non-invasive technique of structural imaging of layers semi-permeable to the infra-red radiation. The aim of the 2018 research campaign at the Banqueting House, conducted within the MOLAB programme under the IPERION CH project, was to determine the present condition of the paintings and thus inform decisions about future conservation planning for these unique paintings

AlGaInN laser diode technology for GHz high-speed visible light communication through plastic optical fiber and water

AlGaInN ridge waveguide laser diodes are fabricated to achieve single-mode operation with optical powers up to 100 mW at ∼420  nm∼420  nm for visible free-space, underwater, and plastic optical fiber communication. We report high-frequency operation of AlGaInN laser diodes with data transmission up to 2.5 GHz for free-space and underwater communication and up to 1.38 GHz through 10 m of plastic optical fiber

Combining OCT and NMR-MOUSE techniques to study the stratigraphy of historical violins: the thickNESS project

In this work, Optical Coherence Tomography (OCT) and Nuclear Magnetic Resonance (NMR-MOUSE) have been applied to precious historical violins made by the most renowned makers of the Italian lutherie, such as Amati, Stradivari and Guarneri ‘del Gesù’, and hosted in the Museo del Violino in Cremona. Several large fragments removed during past restorations from instruments produced by the luthiers Stainer, Gasparo da Salò, Maggini and Guadagnini, as well as laboratory models simulating musical instruments stratigraphy, were further examined. OCT study was carried out with a prototype high-resolution portable SdOCT instrument providing layer thickness measurements and information about the presence of particles, cracks and delaminations. NMR analyses were performed with a Magritek Kea spectrometer and a Profile NMR-MOUSE (PM5) giving information on the wood density and elasticity, the last one possibly related to adopted treatments. The analyses have been conducted within the MOLAB Transnational Access - EU H2020 Project IPERION CH (thickNESS Project). Data interpretation is still in progress and promising results are expected to reveal in-depth insight into the finishing violin making process. These outcomes will be integrated with the results from UVIFL, FT-IR, Raman and XRF techniques in order to set up a methodology which allowed researchers to non-invasively characterize the stratigraphy of historical violins

From IR to X-rays: approaches to go through the coating system of historical bowed string musical instruments

Some historical bowed string musical instruments produced in Italy from the 16th to 18th Centuries are considered until now peak-quality masterpieces of the violin-making art. Technical skills were mostly lost after the disappearance of the prominent workshops, and nowadays ancient methods and materials are charming secrets to be revealed by scientific techniques. This work discusses the results obtained by investigating the complex coating systems on bowed string instruments produced by four violin-makers, namely: Jacobus Stainer, Gasparo da Salò, Giovanni Paolo Maggini and Lorenzo Guadagnini. They were selected in order to represent convincingly - albeit not exhaustively - the variety of situations that can be encountered when multi-layered coatings on historical bowed string instruments are considered. The coating systems have been investigated though micro-invasive and non-invasive procedures [1], employing UV-imaging, portable X-ray fluorescence, optical microscopy, scanning electron microscopy coupled with energy dispersive X-ray spectrometry and Fourier transform infrared microscopy. In addition, two tomographic techniques (synchrotron radiation micro-computed tomography and optical coherence tomography) have been used to image the finishing layers spread on the wood substrate [2,3]. Chemical investigations and images on cross-sections have been compared with the morphological view obtained by tomography, with particular attention to the ability of the tomographic insight to distinguish and measure the various overlying layers, and to highlight the presence of dispersed particles