Spectral database of Renaissance fresco pigments by LIBS, LIF and colorimetry

A set of about 70 fresco samples made with pigments and binders typical of the Renaissance period in Rome has been characterized by LIBS, LIF and colorimetric measurements in order to build an as much as possible complete database. Aiming at providing the restorers and art historians with a useful tool for the study of ancient frescoes, the samples have been prepared in agreement with the Cennino Cennini recipes for both materials and procedures. Afterward, the obtained spectral data have been processed by means of multivariate analysis methods in order to find the most significant features that can help in fast characterization and recognition of real unknown specimens

Real-time diagnosis of Historical Artworks by Laser-Induced Fluorescence

Laser-induced fluorescence (LIF) is a powerful remote analysis tool that has been successfully applied to the real-time diagnosis of historical artworks, allowing the observation of features invisible to the naked eye, as pigment composition, biological attack and restoration technique. This paper presents a LIF-based optical radar and reports on the results of its deployment during a field campaign conducted in February 2010 in Seville, Spain

Report on LIF measurements in Seville. Part 2: Santa Ana church

A scientific cooperation between ENEA UTAPRAD (Frascati) and the Natural Sciences Department of the “Pablo de Olavide” University in Seville, has started aimed at developing and testing innovative diagnostic instrumentation for Cultural Heritage preservation. Here we report the results obtained in a joint campaign carried on in Seville during February 2010 in the Santa Ana church in Seville (SP). Several wood paintings have been thoroughly investigated by means of Laser Induced Fluorescence scan system along the lines of the Research Pro ject “Non Destructive Techniques” managed by IAPH (Consejería de Cultura de la Junta de Andalucía).The field activities, developed as part of a conservation project carried out by IPAH, were devoted to the determination of retouches, traces of former restorations and detection of chemicals (wax, consolidants, etc.) on the surface under analysis not otherwise documented

Report on LIF measurements in Seville. Part 1: Virgen del Buen Aire chapel

Within the frame of a scientific cooperation between ENEA UTAPRAD (Frascati) and UPO Natural Sciences Dep. (Seville), aimed at developing and testing innovative diagnostic instrumentation for Cultural Heritage preservation, this report deals with results obtained in a joint campaign carried on in Seville during February 2010. Namely the data acquired by the ENEA LIF scanning system operated on fresco’s in Virgen del Buen Aire Chapel are presented here. The Virgen del Buen Aire Chapel has been studied according to the Research Project of “Non Destructive Techniques” managed by IAPH (Consejería de Cultura de la Junta de Andalucía). The results have been also implemented as part of a conservation project carried out by IAPH. LIF images are discussed in term of evaluating former restoration actions, in particular retouches on pigments and consolidant additions on a painted wall and two vaults. Statistical approaches and projection operators have been utilized for elaborating the images in order to handle the large number of spectra collected in each scanned point by our hyper-spectral system

Stand-Off Device for Plastic Debris Recognition in Post-Blast Scenarios

The fast analysis of crime scenes is a very critical issue for investigators that should collect, as much as possible, all and only meaningful evidence, and rapidly bring back to normality the involved area. With the scope to respond to the end user’s requirements, the project FORLAB (Forensic Laboratory for in-situ evidence analysis in a post blast scenario) has set, as its main goal, to develop a system of sensors for fast screening of post-blast scenes. In this frame, a new sensor based on laser induced fluorescence has been developed for standoff individuation and localization of plastic debris in post-blast scenarios. The system can scan large areas in short times (in some cases, minutes) providing real-time images of the scene where material discrimination is highlighted. In fact, the combined use of a laser source with a high repetition rate and of a signal collection setup based on a fixed intensified charged coupled device (ICCD) with a large field of view has allowed for the brief duration of the scanning process. In addition, dedicated software elaborates the fluorescence data obtained from the targets and retrieves a chemical characterization useful for material recognition

Luminescence reveals variations in local structural order of calcium carbonate polymorphs formed by different mechanisms

International audienc

Laser-induced fluorescence (LIF) and reflectance measurements of medieval frescoes by Giusto de' Menabuoi in the Padua Baptistery

International audienceLaser-induced fluorescence (LIF) is a powerful remote analysistool that has been applied successfully to the diagnosis ofhistorical work of arts,1 allowing the observation of featuresinvisible to the naked eye, such as biological attack2 andrestoration interventions.3 LIF is fast, remote, non-invasive,sensitive and specific: these advantages have encouragedits application in real-time monitoring of historical frescoes,mosaics, paintings, sculpture, decorated façades and similarobjects. The aim of the work described here was to performremote diagnostics of a fresco by reflectance and laser-inducedfluorescence measurements.The results that are presented were made with the ENEApatentedLIF hyperspectral scanning system, which is capableof collecting fluorescence images by scanning large areas ofcultural heritage surfaces. The measurements were obtainedduring a field campaign carried out in June 2010 on frescoesby Giusto de’ Menabuoi in the Padua Baptistery.Using univariate and multivariate data processing, includingfalse colour imaging, principal component analysis andspectral angle mapping, the presence of surface consolidantswas detected and mapped. The results that were obtained willhelp restorers to define future conservation action

Unusual Luminescence of Quartz from La Sassa, Tuscany: Insights on the Crystal and Defect Nanostructure of Quartz

Quartz from La Sassa (Tuscany, Italy) presents a unique luminescence related to intrinsic and extrinsic defects in the crystal lattice due to the growth mechanisms in hydrothermal conditions. The bright fluorescence under the UV lamp was apparent to collectors since the early 1970s, and it entered the literature as a reference case of yellow-luminescent quartz. Early reports present the history of the discovery, the geological context, and preliminary luminescence measurements of the quartz nodules, suggesting various activators as potentially responsible of the peculiar luminescence effects: uranyl groups (UO22+), rare earths (Tb3+, Eu3+, Dy3+, Sm3+, Ce3+) and polycyclic aromatic compounds (PAH). Here, we report a full investigation of the La Sassa material, by a multi-analytical approach encompassing cathodoluminescence optical microscopy (OM-CL), laser-induced fluorescence (LIF), wavelength resolved thermally stimulated luminescence (WR-TSL), trace elements analysis by mass spectrometry (ICP-MS) and Raman spectroscopy (RS). The results provide a significant step forward in the interpretation of the luminescence mechanisms: the main luminescent centres are identified as alkali-compensated (mainly Li+ and Na+, K+ and H+) aluminum [AlO4/M+]0 centres substituting for Si, where the recombination of a self-trapped exciton (STE) or an electron at a nonbridging oxygen hole centre (NBOHC) are active

BIODETERIORATION OF ROMAN HYPOGEA: THE CASE STUDIES OF THE CATACOMBS OF SS MARCELLINO AND PIETRO (ROME, ITALY)

The Catacombs of SS. Marcellino and Pietro are Christian cemeteries, excavated between the 3rd and 5th centuries CE, comprising of 18000 m2 of corridors and chambers around 16 m under ground level. As is the case for all the other Roman Catacombs, they are important religious and cultural heritage resources that are visited by thousands of tourists each year. In order to be visited these sites need to be illuminated and unfortunately, when this intervention is coupled with the environmental conditions of the catacombs there is generally a promotion of phototrophic biofilm growth on the stone surfaces. These growths can cause aesthetic damage to the sites and can also threaten their durability. There is no information available on these consortia (the site was only recently opened to the public in 2014) and so there is a need to characterise these microbial communities in order to compare them with results from other previously studied Roman Catacombs. Phototrophic microorganisms were investigated by microscopy and culture methods on samples collected with non-invasive methods from different illuminated sites along the tourist path. Innovative and non-destructive strategies involving singular and combinations of essential oils are presently being tested and developed to prevent biodeterioration of these sites. Tests are being carried to determine the effect of the oils not only on the biofilms but also on the decorated substrates (frescoed plaster) to determine any discolouration that may occur. A Lidar scanning prototype (developed By ENEA) has been used to perform both laser induced fluorescence (LIF) and reflectance measurements on the decorated stone substrate before and after the application of the essential oils. The obtained fluorescence maps of the treated surface areas in this on going study will identify any eventual colorimetric variations due to oil application which will be evaluated by the reflectance results and data from a standard contact colorimeter

Laser-induced fluorescence study of medieval frescoes by Giusto de’ Menabuoi

International audienceLaser-induced fluorescence (LIF) is a powerful remote and non-invasive analysis technique that has been successfully applied to the real-time diagnosis of historical artworks. Hyperspectral images collection on fresco's and their false colours processing allowed to reveal features invisible to the naked eye and to obtain specific information on pigments composition and consolidants utilization, the latter also related to former restorations. This report presents the results obtained by ENEA LIF scanning system during a field campaign conducted in June 2010 on fresco's by Giusto de' Menabuoi in the Padua Baptistery. The data collected by LidArt allowed the detection of Paraloid B72 and Movilith/Primal AC33, guiding the restorers in their conservation actions