title: Non-invasive characterization of colorants by portable diffuse reflectance infrared Fourier transform (DRIFT) spectroscopy and chemometrics.
abstract: During the last years the need for non-invasive and non-destructive analytical methods brought to the development and application of new instrumentation and analytical methods for the in-situ analysis of cultural heritage objects. In this work we present the application of a portable diffuse reflectance infrared Fourier transform (DRIFT) method for the non-invasive characterization of colorants prepared according to ancient recipes and using egg white and Gum Arabic as binders. Approximately 50 colorants were analyzed with the DRIFT spectroscopy: we were able to identify and discriminate the most used yellow (i.e. yellow ochres, Lead-tin Yellow, Orpiment, etc.), red (i.e. red ochres, Hematite) and blue (i.e. Lapis Lazuli, Azurite, indigo) colorants, creating a complete DRIFT spectral library. The Principal Component Analysis-Discriminant Analysis (PCA-DA) was then employed for the colorants classification according to the chemical/mineralogical composition. The DRIFT analysis was also performed on a gouache painting of the artist Sutherland" and the colorants used by the painter were identified directly in-situ and in a non-invasive manner.
authors.affiliation: Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale, Viale Teresa Michel 11, Alessandria, Italy; ISALIT S.r.l., Via A. Canobio 4/6, Novara, NO, Italy.
authors.forename: Marcello
authors.initials: M
authors.lastname: Manfredi
authors.affiliation: Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale, Viale Teresa Michel 11, Alessandria, Italy; ISALIT S.r.l., Via A. Canobio 4/6, Novara, NO, Italy. Electronic address: elettra.barberis@uniupo.it.
authors.forename: Elettra
authors.initials: E
authors.lastname: Barberis
authors.affiliation: Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale, Viale Teresa Michel 11, Alessandria, Italy.
authors.forename: Maurizio
authors.initials: M
authors.lastname: Aceto
authors.affiliation: Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale, Viale Teresa Michel 11, Alessandria, Italy.
authors.forename: Emilio
authors.initials: E
authors.lastname: Marengo
keywords: Chemometrics; Colorants characterization; DRIFT spectroscopy; In-situ technique; Non-invasive analysis; Surface analysis