Spectral investigations on 1000 £ banknotes throughout Italian Republic Eleonora Imperio a , Eliana Calò b , Ludovico Valli c , Gabriele Giancane b, * a Department of Innovation Engineering, Università del Salento, Via Monteroni, I-73100 Lecce, Italy b Department of Cultural Heritage, Università del Salento, Via D. Birago, I-73100 Lecce, Italy c Department of Biological and Environmental Science and Technologies, Università del Salento, Via Monteroni, 73100 Lecce, Italy ARTICLE INFO Article history: Received 12 March 2015 Received in revised form 14 May 2015 Accepted 20 May 2015 Available online 22 May 2015 Keywords: Italian banknotes Fake specimens Watermark Security marks Serial numbers ABSTRACT In the present manuscript it is reported a study carried out by means of micro-Raman and infrared spectroscopy on banknotes used in Italy during more than 50 years, since 1947 until 2001. For each specimen, three different features of the banknote (serial number, watermark and security mark) were considered and the measurements were repeated on three different banknotes of the same type. Differences were revealed in the paper banknote composition, red color used for the security mark and serial number black printing ink. Then, two certified fakes were analyzed and significant shifts on the main peak of red color pigment were revealed. ã2015 Elsevier B.V. All rights reserved. 1. Introduction Banknotes have been largely studied to obtain information about their composition in order to individuate counterfeit banknotes. The issue of Euros in 2001, meanwhile, opened a new perspective in the study of the national banknotes, such as Pesetas in Spain, Franc in French, Mark in Germany and Lira in Italy. These paper-moneys, like the ancient coins, can be now considered a cultural heritage, with a huge historical and social value. Furthermore, as already reported in the literature, vibrational spectroscopy, namely Raman and infrared techniques, allow to investigate the banknotes in a non-destructive and minimally invasive manner [1–5]. Raman spectroscopy and infrared tech- nique in attenuated total reflection (ATR) mode do not need any preparation of the specimens. The versatility of these spectro- scopic methods has been employed in the forensic science to provide the fingerprint of a counterfeit. In fact, Raman and infrared spectra of different types of inks, pigments and papers are reported for banknotes in scientific papers [6,7]. In this context, we propose a detailed study of Raman and infrared spectra of banknotes 1000 lira emitted in Italy since 1947 to 2001, with drastic difference in the size, form, design and material composition among the specimens. The aim of this research is to propose an objective time-line to discriminate authentic and counterfeit specimens but, on the other side, it can supply important information for monitoring the conservation status of the cultural heritage. 2. Materials and methods PerkinElmer Spectrum One instrument in ATR (attenuated total reflection) mode was used to record the infrared spectra of the samples. Because of the non-destructiveness of the employed set- up, every single specimen was directly placed onto the ATR plate with no further preparation and an optimal contact between the surface of the sample and the diamond crystal was ensured by means of a piston [8]. For all samples, thirty-two scans were collected with 4 cm 1 resolution in the range between 4000 and 600 cm 1 . Samples were also analyzed by a Horiba XploRA micro- Raman spectrometer coupled to an Olympus BX-41 confocal microscope. The excitation source was a 785 nm (90–100 mW) laser. To prevent any sample alteration, laser power at the sample surface was reduced by neutral density filters to a value between 0.25 and 0.001mW, on an estimated spot size of 1064 mm. Raman signal was collected using a 100 microscope objective. An acquisition time of 30 s and 20 scans were carried out for each spectrum (spectral range 100–3000 cm 1 ). One thousand lire (1000 £) samples were taken from a private collection which includes specimens from the first issue for the Italian Republic in 1947 until the last issue in 2002 (see Table 1). The analyses have been focused on watermarks, security marks and serial numbers, * Corresponding author. Tel.: +39 0832297374; fax: +39 0832297374. E-mail address: gabriele.giancane@unisalento.it (G. Giancane). http://dx.doi.org/10.1016/j.vibspec.2015.05.004 0924-2031/ ã 2015 Elsevier B.V. All rights reserved. Vibrational Spectroscopy 79 (2015) 52–58 Contents lists available at ScienceDirect Vibrational Spectroscopy journal homepage: www.elsevier.com/locate/vibspec