title: Discovering Hidden Painted Images: Subsurface Imaging Using Microscale Spatially Offset Raman Spectroscopy.
abstract: We demonstrate for the first time the mapping capability of micro-spatially offset Raman spectroscopy (micro-SORS). The technique enables to form noninvasive images of thin sublayers through highly turbid overlayers. The approach is conceptually demonstrated on recovering overpainted images in situations where conventional Raman microscopy was unable to visualize the sublayer. The specimens mimic real situations encountered in Cultural Heritage that deal, for example, with hidden paintings vandalized with graffiti or covered by superimposed painted layers or whitewash. Additionally, using a letter as a hidden image, we demonstrated the micro-SORS potential to reconstruct also a hidden writing covered, for example, with paper sheets that cannot be easily removed. Potential applications could also include other disciplines such as polymers, biological, catalytic, and forensic sciences where thin, highly turbid layers mask chemically distinct subsurface structures.
authors.affiliation: Consiglio Nazionale delle Ricerche, Istituto per la Conservazione e la Valorizzazione dei Beni Culturali (ICVBC) , Via Cozzi 53, 20125, Milano, Italy.
authors.forename: Alessandra
authors.identifier: 0000-0002-0948-5767
authors.initials: A
authors.lastname: Botteon
authors.affiliation: Consiglio Nazionale delle Ricerche, Istituto per la Conservazione e la Valorizzazione dei Beni Culturali (ICVBC) , Via Cozzi 53, 20125, Milano, Italy.
authors.forename: Claudia
authors.initials: C
authors.lastname: Conti
authors.affiliation: Consiglio Nazionale delle Ricerche, Istituto per la Conservazione e la Valorizzazione dei Beni Culturali (ICVBC) , Via Cozzi 53, 20125, Milano, Italy.
authors.forename: Marco
authors.initials: M
authors.lastname: Realini
authors.affiliation: Consiglio Nazionale delle Ricerche, Istituto per la Conservazione e la Valorizzazione dei Beni Culturali (ICVBC) , Via Cozzi 53, 20125, Milano, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Colombo
authors.affiliation: Central Laser Facility, Research Complex at Harwell, STFC Rutherford Appleton Laboratory , Harwell Oxford, OX11 0QX, United Kingdom.
authors.forename: Pavel
authors.initials: P
authors.lastname: Matousek