Maria Francesca Alberghina

Integrated three-dimensional models for noninvasive monitoring and valorization of the Morgantina silver treasure (Sicily)

Abstract. The Morgantina silver treasure belonging to the Archaeological Museum of Aidone (Sicily) was involved in a three-dimensional (3-D) survey and diagnostics campaign for monitoring the collection over time in anticipation of their temporary transfer to the Metropolitan Museum of Art in New York for a period of 4 years. Using a multidisciplinary approach, a scientific and methodological protocol based on noninvasive techniques to achieve a complete and integrated knowledge of the precious items and their conservation state, as well as to increase their valorization, has been developed. All acquired data, i.e., 3-D models, ultraviolet fluorescence, x-ray images, and chemical information, will be made available, in an integrated way, within a web-oriented platform, which will present an in-progress tool to deepen existing archaeological knowledge and production technologies and to obtain referenced information of the conservation state before and after moving of the collection from its exposure site.

Characterization of foxing stains in early twentieth century photographic and paper materials

Abstract The subject of this present work is a group of nine historical pictures shot in Palermo by the Sicilian photographer E. Interguglielmi in 1912. They are nine matte-collodion prints mounted on the original cardboard supports and all of them show foxing stains affecting the paper surface. In order to characterise the chemical composition of the supports and investigate foxing spots, non-destructive and micro-destructive analysis were carried out. X-rays fluorescence (XRF) analysis was used to characterise the elemental composition of all the mounting boards, allowing a comparison between the foxing spots and non-affected areas. Laser-Induced Breakdown Spectroscopy was used to investigate the presence of lower atomic number elements, not detectable by XRF, while SEM imaging allowed the investigation of surface appearance and nature of original paper samples from the cardboards.

LIBS and XRF analysis for a stratigraphic study of pictorial multilayer surfaces

The study of painting materials is a primary goal for the historical and artistic characterization of works of artbecause it provides useful information about the original materials and their degradation products, the paintingstechnique and any conservation treatments. However, the archaeometric investigations are very complex because theneed to safeguard the Cultural Heritage makes necessary the use of non or micro invasive techniques. Among thepossible analytical approaches, Laser-Induced Breakdown Spectroscopy, supported by X-ray Fluorescencespectroscopy for a faster elements identification, allows stratigraphic analysis with high spatial resolution enough todiscriminate different layers. Moreover, an integrated approach based on XRF and LIBS investigation is particularlyuseful for the complementarities of the outcomes in terms, both of investigated thicknesses and detectable elementalcontent.This paper aims to validate, in the archaeometry field, the use of LIBS for stratigraphic investigation of paintedsurfaces/objects by means of analytical results obtained from original fragments of mural paintings originating fromdifferent sites and artistic eras. Indeed the focus of this work is to determine the optimum parameters for bothtechniques in order to acquire the maximum information with the least damage to the works of art.The results have demonstrated the usefulness of the LIBS investigation, through that it has been possible toreveal chemical elements undetectable by XRF and to analyse the stratigraphic sequence of paint layers from thesurface up to the support layer. Furthermore they have provided good insight into the different painting layers byconfirming the potential of the LIBS to carried out stratigraphic analyses in a micro destructive way.

Double laser LIBS and micro-XRF spectroscopy applied to characterize materials coming from the Greek-Roman theater of Taormina

The laser-induced breakdown spectroscopy (LIBS) is an applied physical technique that has shown, in recent years, its great potential for rapid qualitative analysis of materials. The possibility to implement a portable instrument that perform LIBS analysis makes this technique particularly useful for in situ analysis in the field of cultural heritages. The aim of this work is to compare the results, obtained by LIBS measurements with X-Ray Fluorescence (XRF) ones, on calcareous and refractory materials coming from the Greek-Roman theater of Taormina. Calibration curves for LIBS and XRF were obtained by measuring certified reference materials and using them as standards. LIBS measurements were performed with a new mobile instrument Modì (Mobile Double pulse Instrument for LIBS Analysis) that use an innovative experimental set-up, based on the use of two suitably retarded laser pulses that greatly improves the potential of this technique for accurate quantitative analysis. XRF analyses were performed with a portable instrument ArtTAX that use a collimated X-Ray beam equipped with a fluxing system of helium gas on the detection path to the aim to detect the lighter elements with a good accuracy. LIBS results have shown that this technique is highly subjected to the sample chemical and physical characteristics.

Surface and volume non-invasive methods for the structural monitoring of the bass-relief 'Madonna con Bambino' (Gorizia, Northern Italy).

Abstract Structural analysis of marble statues, carried out by non-invasive and in situ methods, is crucial to define the state of conservation of the artworks and to identify the deterioration phenomena that can affect them. In this work, we combined in situ non-destructive techniques, ultrasonic tomography (US), ultraviolet-induced visible fluorescence (UV-IF) and X-ray fluorescence (XRF) to study the bass-relief ‘Madonna con Bambino’ (Gorizia, Italy). The US revealed the presence of some metallic pivots, associated with areas of high sound velocity; moreover, a more degraded area has been identified in the lower part of the bass-relief. The acquired UV-IF image confirmed the presence of surface degradation, allowing a preliminary evaluation of the extension of a fracture, from surface to bulk. In addition, the different materials (both original and/or integrations) that compose the studied surface have been identified. The XRF has contributed to define the nature of the inorganic materials applied during undocumented previous restoration works on the surface as filler for lacunae.

X-ray CT imaging as a scientific tool to study the capillary water absorption in sedimentary rocks used in cultural heritages

This paper proposes the X-Ray CT imaging as appropriate tool for investigating the capillary water absorption in sedimentary rocks. This technique, in fact, provides information useful for deeping the knowledge about of the porosity and the kinetics of the water capillary absorption in porous materials. The possibility to improve in non invasive manner, the understanding of this phenomenon, constitutes a fundamental aspect to take actions in the restoration and conservation of lapideous artifact and monuments from cultural heritages. The investigated sedimentary rocks come from different Sicilian quarries and were used for the building of the Greek temples in the archaeological areas of Agrigento, Selinunte and in the baroque monuments of the Val di Noto area. The image acquisition was carried out at different times after contact with water. The wetting front progression along the height of the sample was evaluated on the basis of the estimated CT attenuation value maps. An average of the CT attenuation values measured by the ROI (Region of Interest) was used to evaluate the mean height of the wetting front, with different CT scans at fixed time intervals after sample wetting, in order to describe the dynamic behaviour of the imbibition process. CT imaging results have shown that the water absorption is highly subject to the sample porous morphology.