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sono riportate potenzialità e problematiche relative all'uso di tecniche di spettroscopia d'immagine per lo studio di pellicole fotografiche a colori degradate

A selection is presented of fiber-optic and micro-optic devices that have been designed and tested for guaranteeing the quality and safety of typical foods, such as extra virgin olive oil, beer, and milk. Scattered colorimetry is used to authenticate various types of extra virgin olive oil and beer, while a fiber-optic-based device for UV-VIS-NIR absorption spectroscopy is exploited in order to obtain the hyperspectral optical signature of olive oil. This is done not only for authentication purposes, but also so as to correlate the spectral data with the content of fatty acids, which are important nutritional factors. A micro-optic sensor for the detection of olive oil aroma that is capable of distinguishing different ageing levels of extra virgin olive oil is also presented. It shows effective potential for acting as a smart cap of bottled olive oil in order to achieve a nondestructive olfactory perception of oil ageing. Lastly, a compact portable fluorometer for the rapid monitoring of the carcinogenic M1 aflatoxin in milk, is experimented.

This paper reports the preliminary results obtained from the data acquired during the diagnostic survey, begun in September 2011, to evaluate the state of conservation of the mural Tuttomondo (1989) by Keith Haring (1958-1990). Multispectral imaging technique, ultra-high resolution photography, ultraviolet (UV), visible (Vis), and near infrared (NIR) Fiber Optic Reflectance Spectroscopy (FORS), colorimetry, and Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS) analysis were performed directly on the mural or on samples taken from the mural to support the conservation intervention, which was focused on cleaning and the subsequent consolidation of the painting. These analyses were carried out as part of the research project "Preventive Conservation of Contemporary Art" (COPAC). The COPAC Project is a 2-year research project (2011-2013) financially supported by the Regione Toscana (Tuscany, Italy) in the PAR-FAS program, Disciplinary Framework Science and Technology for the Safeguard and Valorisation of Cultural Heritage. The COPAC 2 Project is a joint effort of research institutions, conservators, city councils, museums, and art collections in Tuscany. COPAC activities are focused mainly on the study of the materials used by contemporary artists to produce their artworks with a twofold goal: defining artworks materials and monitoring their conservation and/or their degradation processes over time. In order to achieve this goal the research team adopted a plan based on the use of several diagnostic methodologies for the study of selected contemporary artworks belonging to museums, galleries, and collections in Tuscany. The purpose of this approach was to acquire as much data as possible about artists' materials and techniques and, also, to monitor both the state-of-conservation of the artworks and the surrounding environmental conditions (Learner, T. 2005; Chiantore, O., Rava, A. 2013). All of the collected data will be used to evaluate the conservation-state of the artworks selected for investigation and to identify their risk factors in order to select the most appropriate preservation practices. The ultimate goal of the COPAC Project is to set up an interactive archive to manage and disseminate the acquired information for the benefit of all of the curatorial and technical participants.

Fluorescence LIDAR imaging has been already proposed in several studies as a valuable technique for the remote diagnostics and documentation of the monumental surfaces, with main applications referring to the detection and classification of biodeteriogens, the characterization of lithotypes, the detection and characterization protective coatings and also of some types of pigments. However, the conservation and documentation of the cultural heritage is an application field where a highly multi-disciplinary, integrated approach is typically required. In this respect, the fluorescence LIDAR technique can be particularly useful to provide an overall assessment of the whole investigated surface, which can be profitably used to identify those specific areas in which further analytical measurements or sampling for laboratory analysis are needed. This paper presents some representative examples of the research carried out in the frame of the PRIMARTE project, with particular reference to the LIDAR data and their significance in conjunction with the other applied techniques. One of the major objectives of the project, actually, was the development of an integrated methodology for the combined use of data by using diverse techniques: from fluorescence LIDAR remote sensing to UV fluorescence and IR imaging, from IR thermography, georadar, 3D electric tomography to microwave reflectometry, from analytical techniques (FORS, FTIR, GC-MS) to high resolution photo-documentation and historical archive studies. This method was applied to a 'pilot site', a chapel dating back to the fourteenth century, situated at 'Le Campora' site in the vicinity of Florence. All data have been integrated in a multi-medial tool for archiving, management, exploitation and dissemination purposes.

The painting Il ritratto della figliastra (Portrait of the Stepdaughter) by Giovanni Fattori (1889, Gallery of Modern Art, Pitti Palace, Florence) was investigated using non-invasive fibre optics reflectance spectroscopy (FORS). The use of compact and transportable instrumentation made it possible to easily record spectra of the polychrome surface at the restorer’s atelier during the restoration work. The results of colour analysis before and after the cleaning procedure of the painting are reported and discussed, together with an attempt at pigment identification.

Methodological aspects of the use of photosensitive materials as light dosimeters in museum monitoring arc investigated. As a case study, a spectroscopic investigation in the 400-700 nm range is developed for Blue Wool Standard No. 1 (BWS1), a colorimetric indicator traditionally used by conservators to obtain a qualitative indication of the risk associated with lighting. Experiments using both artificial and natural light-aging were performed on BWS1 samples and a set of reflectance spectra was non-invasively collected during the aging process at increasing light-doses. A portable device based on fibre-optics technology, operating in real time, was used for the spectral acquisition. The problem of calibrating the BWS1 response to the light was investigated using the data-set of artificially light-aged samples, and different calibration models were compared. The calibration curves were then used to estimate the alteration, due to the possible synergistic action of light and other factors, which occurred in BWS1 samples naturally aged by exposure in situ. A method to account semi-quantitatively,for the cumulative action of light and other environmental agents is proposed, by introducing the concept of 'equivalent light-dose', in terms of which the overall risk factor call be evaluated.

be clearly distinguishable by simple visual examination, so that a simple reading can be made on site with no specific measuring equipment. Dosimeters usually provide a very simplified model and, in reality, their response function cannot be expected to reproduce exactly that of artefacts under the same conditions. Rather, the sensor should be used for semi-quantitative indications by ensuring that its behaviour can suitably simulate the reaction under analysis (e.g. discolouration or corrosion). In this research, the environmental factor under examination was light, and the sensors developed were specifically tailored to respond to the damaging effects of light. Light induces photochemical reactions in materials which may result in a change in the appearance of objects (e.g. fading or chromatic balance) [1]. It is well established that any unnecessary light exposure should be avoided for art objects and archival materials on display [2]. Moreover, it has to be taken into account that these reactions can also be modified or accelerated by other environmental parameters such as temperature, humidity, external atmospheric and indoor air pollution This paper presents the development and optimization of an ultrasensitive light dosimeter, especially designed for the preventive risk assessment of damage to highly photosensitive artefacts. This indicator, named LightCheck ® Ultra, is composed of a photosensitive dye/polymer layer applied on a paper support. The indicator is characterized by a progressive colour variation as the exposure to light increases. Initially blue, the colour successively changes through purple and pink to white, under the effect of visible light. The colour variation was investigated under different environmental conditions. The light-induced alterations under study were evaluated using various light sources and illuminance levels. The impact of other factors unconnected to light (such as temperature, humidity, indoor air pollution – atmospheric and volatile organics – and oxygen) was also studied. The behaviour of the indicator in the field in selected museums and historic houses was assessed in parallel with the laboratory experiments at each development stage. Finally, the calibration was carried out and a reference colour scale was provided for fast and easy reading of the indicator. By means of this reference colour scale, the colour exhibited by the dosimeter after an exposure can be easily correlated to a quantitative indication of the light dose received. The phases of development and testing of this novel light dosimeter are presented in detail, from the early design to the final product., Resumen — Este artículo presenta el desarrollo y optimización de un dosímetro ultrasensible de luz, especialmente diseñado paravalorar, de manera preventiva, los riesgos de daño en objetos altamente fotosensibles. Este indicador, llamado LightCheck® Ultra,se compone de una capa de colorante fotosensible/polímero aplicado sobre un soporte de papel. El indicador se caracteriza por unavariación de color progresiva según va aumentando la exposición a la luz. Inicialmente azul, el color va cambiando sucesivamentehacia el púrpura, y del rosa al blanco, bajo el efecto de la luz visible. Se investigó la variación del color bajo diferentes condicionesambientales. Se evaluaron las alteraciones inducidas por la luz utilizando diferentes fuentes y niveles de iluminación. El impactode otros factores no relacionados con la luz (como temperatura, humedad, polución en interiores, compuestos orgánicos atmosféricosvolátiles – y oxígeno) también fue investigado. El comportamiento del indicador en su localización proyectada (para edificioshistóricos o museos) se valoró en relación con los experimentos llevados a cabo en el laboratorio en las diferentes etapas del proceso.Finalmente, se llevó a cabo la calibración, y se suministró una carta o escala de color con el fin de conseguir una lectura rápida yfácil. Por medio de esta escala de color de referencia el color exhibido por el dosímetro después de la exposición puede ser fácilmentecorrelacionado con una indicación cuantitativa de la dosis de luz recibida. Se presentan en detalle las fases de desarrollo y pruebade este novedoso dosímetro de luz, desde el diseño inicial hasta el producto final., Résumé — Cet article décrit la mise au point et l’optimisation d’un dosimètre de lumière ultrasensible, spécialement conçupour l’évaluation préventive des risques de dégradation des objets hautement photosensibles. Cet indicateur, appelé LightCheck®Ultra, est composé d’une couche de polymère et de colorant photosensible appliqué sur un support papier. L’indicateur estcaractérisé par une variation progressive de la couleur lorsque l’exposition à la lumière augmente. Initialement bleue, la couleurpasse successivement au pourpre et au rose, puis au blanc, sous l’effet de la lumière visible. La variation de couleur a étéétudiée sous diverses conditions environnementales. Les altérations dues à la lumière faisant l’objet de l’étude ont été évaluéesau moyen de diverses sources de lumière et de divers niveaux d’éclairement. L’impact d’autres facteurs non liés à la lumière(comme la température, l’humidité, la pollution de l’air à l’intérieur – pollution atmosphérique et composés organiques volatils– et l’oxygène) a également été étudié. Le comportement de l’indicateur sur le terrain, dans des musées ou maisons historiquessélectionnés, a été évalué en parallèle avec des mesures en laboratoire à chaque étape de la mise au point. Finalement, l’étalonnagea été mené à bien et une échelle de couleur de référence a été établie, permettant une lecture rapide et aisée de l’indicateur. Au moyen de cette échelle de référence de couleurs, la couleur affichée par le dosimètre après une exposition peut être aisément corréléeà l’évaluation quantitative de la dose de lumière reçue. Les phases de mise au point et d’essai de ce nouveau dosimètre de lumièresont présentées en détail, depuis la conception initiale jusqu’au produit final.