Spectrochimica Acta Part A 91 (2012) 352–359 Contents lists available at SciVerse ScienceDirect Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy j our na l ho me p age: www.elsevier.com/locate/saa Non invasive analysis of miniature paintings: Proposal for an analytical protocol Maurizio Aceto a,b,∗ , Angelo Agostino c,d,1 , Gaia Fenoglio c,d,1 , Monica Gulmini e,2 , Valentina Bianco e,2 , Eleonora Pellizzi f,3 a Dipartimento di Scienze dell’Ambiente e della Vita (DISAV), Università degli Studi del Piemonte Orientale, viale Teresa Michel, 11-15121 Alessandria, Italy b Centro Interdisciplinare per lo Studio e la Conservazione dei Beni Culturali (CenISCo), Università degli Studi del Piemonte Orientale, via Manzoni, 8-13100 Vercelli, Italy c Dipartimento di Chimica Generale e Chimica Organica, Università degli Studi di Torino, corso M. d’Azeglio, 48-10125 Torino, Italy d NIS (Nanostructured Interfaces and Surfaces) Center of Excellence, via Giuria, 7-10125 Torino, Italy e Dipartimento di Chimica Analitica, Università degli Studi di Torino, via P. Giuria, 5-10125 Torino, Italy f Centre de Recherche sur la Conservation des Collections, Muséum National d’Histoire Naturelle, 36 rue Saint Hilaire, 75005 Paris, France a r t i c l e i n f o Article history: Received 7 December 2011 Received in revised form 27 January 2012 Accepted 6 February 2012 Keywords: Protocol Manuscripts Miniature painting Non invasive a b s t r a c t The characterisation of palettes used in manuscript illumination is a hard analytical task, due to value and fragility of the analysed items. Analysis on miniatures must be necessarily non-invasive and fast and requires the use of several techniques since no single technique is able to provide all information needed. In this work a four-step analytical protocol is proposed for non-invasive in situ characterisa- tion of miniature paintings. The protocol allows the identification of coloured materials through the use in sequence of complementary techniques, so as to fully exploit the information given by each instrument. Preliminarily to the instrumental investigations on ancient books and miniatures is the com- pilation of spectroscopic databases obtained from “standard” samples prepared on parchment, according to recipes described in medieval artistic treatises. The protocol starts with an extensive investigation with UV–visible spectrophotometry in reflectance mode, collecting spectra from all the most significant painted areas in the manuscript; chemometric classification is then performed on the spectra to highlight areas possibly containing the same materials. The second step involves in-depth inspection of miniatures under optical microscopy that guides the interpretation of reflectance spectra. XRF spectrometry is then performed to characterise pigments and metal layers, to verify the presence of overlapping layers, to identify mordants in lakes and to recognise minor components that may yield information concern- ing provenance; in addition, chemometric classification can be performed on element concentrations to highlight similar areas. Finally, Raman spectroscopy is used to shed light on the uncertain cases, if still present. Such a procedure offers a wealth of information without causing stress to the manuscripts under analysis. © 2012 Elsevier B.V. All rights reserved. 1. Introduction The characterisation of palettes used in miniature painting is an important task as a great amount of information can be obtained at the disposal of art historians and conservators. Several analyti- cal techniques can be used, as reviewed by Clarke [1], providing a wide range of different information. In particular, the knowledge ∗ Corresponding author at: Dipartimento di Scienze dell’Ambiente e della Vita (DISAV), Università degli Studi del Piemonte Orientale, viale Teresa Michel, 11- 15121 Alessandria, Italy. Tel.: +39 0131 360265; fax: +39 0131 360250. E-mail addresses: maurizio.aceto@unipmn.it (M. Aceto), angelo.agostino@unito.it (A. Agostino), monica.gulmini@unito.it (M. Gulmini), pellizzi@mnhn.fr (E. Pellizzi). 1 Tel.: +39 011 6707585; fax: +39 011 6707585. 2 Tel.: +39 011 6707618; fax: +39 011 6707615. 3 Tel.: +33 1 40795328. of the materials employed helps in selecting the proper condition for conservation and offers useful information to correctly define restoration plans. The recognition the pigments employed may give indication about authenticity, may lead to identify scriptoria or to recognise the intervention of different hands upon a series of codices or within a single manuscript [2–5]. One should however be aware that a thorough investigation on an illuminated manuscript is a hard task, since miniatures are among the most precious and fragile artworks. Many problematic aspects must be considered: sampling from miniatures is hardly, if ever, allowed by owners and institutions, so that only in situ analysis can be performed; and also the use of analytical techniques working at contact with the sample, such as ATR-IR, is generally not per- mitted; moreover, while performing analytical sessions, prolonged opening of manuscripts can cause stress to painting layers and to parchment itself, so that, after few hours, analytical session must be closed. Finally, there is a need to rapidly acquire the analytical 1386-1425/$ – see front matter © 2012 Elsevier B.V. All rights reserved. doi:10.1016/j.saa.2012.02.021