title: An uncovered XIII century icon: particular use of organic pigments and gilding techniques highlighted by analytical methods.
abstract: The restoration of a panel painting depicting a Madonna and Child listed as an unknown Tuscan artist of the nineteenth century, permitted the hidden original version, a XIII century Medieval icon to be uncovered. It is discovery provided the opportunity for an extensive in situ campaign of non-invasive analytical investigations by portable imaging and spectroscopic techniques (infrared, X-ray fluorescence and diffraction, UV-Vis absorption and emission), followed by aimed micro-destructive investigations (Raman and SEM-EDS). This approach permitted characterization of the original ground and paint layers by complementary techniques. Furthermore, this protocol allowed supplementary particularities of great interest to be highlighted. Namely, numerous original gilding techniques have been accentuated in diverse areas and include the use of surrogate gold (disulphur tin), orpiment as a further false gold and an area with an original silver rich layer. Moreover, pigments including azurite mixed with indigo have been non-invasively identified. Micro-invasive analyses also allowed the diagnosis of organic colorants, namely, an animal anthraquinone lake, kermes and an unusual vegetal chalcone pigment, possibly safflower. The identification of the latter is extremely rare as a painting pigment and has been identified using an innovative adaption to surface enhanced Raman techniques on a cross-section. The resulting data contributes new hypotheses to the historic and artistic knowledge of materials and techniques utilized in XIII century icon paintings and ultimately provides scientific technical support of the recent restoration.
authors.affiliation: Associazione Laboratorio di Diagnostica per i Beni Culturali di Spoleto, Piazza Campello 2, 06049 Spoleto (PG), Italy.
authors.forename: Alessia
authors.initials: A
authors.lastname: Daveri
authors.affiliation: Istituto CNR di Scienze e Tecnologie Molecolari CNR-ISTM, c/o Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy. Electronic address: b.bd.doherty@talk21.com.
authors.forename: Brenda
authors.initials: B
authors.lastname: Doherty
authors.affiliation: Istituto CNR di Scienze e Tecnologie Molecolari CNR-ISTM, c/o Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy.
authors.forename: Patrizia
authors.initials: P
authors.lastname: Moretti
authors.affiliation: Istituto CNR di Scienze e Tecnologie Molecolari CNR-ISTM, c/o Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy.
authors.forename: Chiara
authors.initials: C
authors.lastname: Grazia
authors.affiliation: Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy.
authors.forename: Aldo
authors.initials: A
authors.lastname: Romani
authors.affiliation: Laboratorio Scientifico della Soprintendenza SPSAE e per il Polo museale della città di Venezia e dei comuni della Gronda Lagunare, Cannaregio 3553, 30131 Venezia, Italy.
authors.forename: Enrico
authors.initials: E
authors.lastname: Fiorin
authors.affiliation: Dipartimento di Chimica, Biologia e Biotecnologie, Università di Perugia, Via Elce di Sotto 8, 06123 Perugia, Italy; Centro SMAArt, c/o Dipartimento di Chimica, Biologia e Biotecnologie, Università degli Studi di Perugia, Via Elce di Sotto 8, I-06123 Perugia, Italy.
authors.forename: Brunetto Giovanni
authors.initials: BG
authors.lastname: Brunetti
authors.affiliation: Associazione Laboratorio di Diagnostica per i Beni Culturali di Spoleto, Piazza Campello 2, 06049 Spoleto (PG), Italy.
authors.forename: Manuela
authors.initials: M
authors.lastname: Vagnini
mesh_terms: D002623:Chemistry Techniques, Analytical / Q000379:methods*; D004396:Coloring Agents / Q000266:history*; D049691:History, Medieval; D010151:Paintings / Q000266:history*; D013050:Spectrometry, Fluorescence; D013056:Spectrophotometry, Ultraviolet
chemical_list: D004396:Coloring Agents
keywords: Complementary analytical techniques; Mosaic gold; SERS on cross-section; Safflower pigment; XIII century Medieval icon