This PDF file contains the front matter associated with SPIE Proceedings Volume 6618, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

The assassination of US President John F. Kennedy on November 22, 1963 transformed the US political landscape as well as the trajectory of subsequent world history. The venue of that tragic event in Dallas was Dealey Plaza, encompassing the "grassy knoll" and the adjacent book-depository and courthouse buildings. For the past forty years the site has undergone a series of conservation/preservation projects in order to make it more suitable for those visiting either in homage or out of curiosity. One such project concerned the deterioration of ironwork within the "Old Red Courthouse". The building architect noted that both stairway railings and floor-support trusses were corroding and deteriorating at accelerating rates. In most situations of this sort the iron would be sandblasted and repainted. However, in this instance sandblasting was inappropriate due to environmental concerns and logistical limitations. Furthermore, historical authenticity criteria dictated that the metal be preserved with its original unpainted finish. In order to avoid excessive floor loading (in this fragile old building) and the generation significant environmental air pollution (within urban Dallas) the general contractor (Avery Mays, Inc.) opted to evaluate photonic divestment. Both laser cleaning and laser glazing were assessed for efficacy and cost effectiveness. Xenon-flashlamp irradiation was evaluated both with and without citric acid augmentation. Citric acid matrix-assisted flashlamp treatment was selected for the preservation of the courthouse ironwork. This decision was based on three advantages over laser treatments: higher speed and cost effectiveness, preservation of the historic "Oliver Foundry" logo markings, and the chemical passivation and rust resistance of the final surface patina.

Optical Coherence Tomography (OCT) is a new, fast-growing technique for non-contact and non-destructive imaging of semi-transparent objects. It has been recently used for diverse applications in art conservation subject - among others it is very well suited for varnish layer imaging and thus for monitoring of varnish removing process, including the laser ablation. In this study we show how to use the OCT technique to obtain the information required for the optimisation of the laser emission parameters like fluency and working regime, with respect to efficiency and safety of the ablation process. We also demonstrate application of the Spectral Optical Coherence Tomography (SOCT) for in-situ monitoring of laser ablation of varnish layer. The frames from OCT tomographic movies demonstrating dynamic processes like melting, resolidification and exfoliation of varnish layer are also presented.

Optical coherence tomography (OCT) is a fast scanning Michelson interferometer originally designed for in vivo imaging of the eye. In 2004, our group along with two other groups first reported the application of OCT to art conservation and archaeology. Since that time we have been conducting a project to investigate systematically the potential of OCT as a new tool for non-invasive examinations of a wide range of museum objects and to design an OCT optimised for in situ use in museums. Here we present the latest results from this ongoing project, which include the determination of the optimum spectral windows for OCT imaging of paintings and painted objects executed using traditional techniques, and non-invasive imaging of the subsurface stratigraphy of painted layers at multiple wavelengths. OCT imaging in assisting spectral pigment identification and in measuring refractive indices of paint will also be presented to illustrate the potential of the technique.

Optical Coherence Tomography (OCT) is a non-invasive and non-destructive technique which is very interesting for the study of works of art. Based on a Michelson interferometer, our device has been adapted for the recording of information in the visible range. This system allows three-dimensional imaging of painting with a micrometer resolution. 3D imaging of pictorial layers is presented where the pigments embedded in the binder are clearly visible. Furthermore, an adapted signal processing gives access to the spectral information issued from pigments. Tests on pigments in powder are presented and show that their spectral responses are different.

Testing the condition of art subjects plays important role in reservation of Cultural Heritage. Optical Coherence Tomography (OCT) is a promising tool for nondestructive cross-sectional evaluating internal structure of material samples like varnish layer of paintings. It is important to use high-speed OCT systems for testing subsurface structure of objects with large area. In the paper, comparison of OCT systems from viewpoint of information capacity is given to select the most appropriate OCT system variant for evaluating 3D multilayer and random tissues. The method of sub- Nyquist sampling of OCT signals is considered that is used to decrease sampling speed in a few times. To provide high noise-immunity and stability when processing OCT signals with randomly variable parameters, the Kalman filtering method has been applied for evaluating sub-Nyquist sampled OCT signals. Experimental results of evaluating materials like varnish layer of paintings are presented and discussed.

One of the most important and sometimes controversial stages of the conservation process is surface cleaning: decisions have to be made regarding partial or complete removal of varnish. Technical considerations include selection of a method that allows a great deal of control in the cleaning process, so that undesired layers can be removed without damage to the underlying ones. Traditional cleaning methods include mechanical or chemical removal, and restorers and conservators work would be considerably helped by the knowledge of the varnish thickness. Up to now thickness measurement has been performed in an invasive way by means of stratigraphy, a well known painting structure investigation technique since half a century. In this work we present an application of Optical Coherence Tomography (OCT), a well-established technique for biomedical applications, for non-destructive measuring of the varnish film thickness during the cleaning process of an ancient painting, the Ritratto Trivulzio by Antonello da Messina. OCT images of three differently cleaned areas on the painting surface were acquired and the results were compared with a spectral characterization of the same areas.

An ongoing concern of conservators when restoring paintings and polychrome objects is the possibility of irreversible damage to the original paint layers. This is the case when removal and replacement of aged varnishes is being considered. Although much work has been conducted to determine the effect of the removal of a varnish on the condition of the (painted) surface, there is still some uncertainty in the conclusions because it has, until recently, been impossible to characterize the original surface under the varnish in situ. A promising solution to this problem is the use of white light confocal profilometry. An initial study has been conducted using this technique to measure the roughness of pencil lines and oil paint under a varnish. Measurements were made on areas up to several mm² in size, at lateral resolutions down to 1 μm, and vertical (roughness) resolutions of 0.1-0.3 μm. It was found that the surface roughness of surfaces under relatively thick varnishes can be measured at relatively low magnification (20x). For thin varnish layers typical of paintings, higher magnifications are required. White light confocal profilometry has thus been shown to be a useful tool for in situ studies of the (sub)surface properties of (painted) objects.

X-ray cone-beam Computed Tomography is a powerful tool for the non-destructive investigation of the inner structure of works of art. With regard to Cultural Heritage conservation, different kinds of objects have to be inspected in order to acquire significant information such as the manufacturing technique or the presence of defects and damages. The knowledge of these features is very useful for determining adequate maintenance and restoration procedures. The use of medical CT scanners gives good results only when the investigated objects have size and density similar to those of the human body, however this requirement is not always fulfilled in Cultural Heritage diagnostics. For this reason a system for Digital Radiography and Computed Tomography of large objects, especially works of art, has been recently developed by researchers of the Physics Department of the University of Bologna. The design of the system is very different from any commercial available CT machine. The system consists of a 200 kVp X-ray source, a detector and a motorized mechanical structure for moving the detector and the object in order to collect the required number of radiographic projections. The detector is made up of a 450x450 mm² structured CsI(Tl) scintillating screen, optically coupled to a CCD camera. In this paper we will present the results of the tomographic investigation recently performed on an ancient globe, created by the famous cosmographer, cartographer and encyclopedist Vincenzo Coronelli.

Within the framework of a French research program, we have developed an optical system dedicated to the measurement of works of art. The purpose is to record the actual optical characteristics of the objects' surfaces in order to be able to display the art object on a screen with a high degree of realism. Three types of data are recorded: 3D shape, true colours and texture. The 3D shape is obtained using a structured light sensor that gives a dense point cloud. A specific procedure allows automatic registration of several point clouds without any contact with the surface. The colours maps are recorded with the structured light sensor's RGB camera and using a built-in lighting system. Both camera and lighting are calibrated using a well-defined procedure. Merging the colour data with the 3D data is straightforward because the same camera is used for both tasks. The texture information is related to the so-called BRDF (Bi-directionnal reflectance distribution function): at each point on the surface, the reflectance is a function of the direction of observation and the direction of illumination. To record this complex texture information, several illumination sources are used, as well as an additional moving camera. Thus, for one 3D point cloud, a complete set of colour pictures is processed to produce texture files that are directly linked to the 3D points. The paper details the measurement procedure as well as the associated data processing. Several results are presented.

A new mobile optical 3D measurement system using phase correlation based fringe projection technique will be presented. The sensor consist of a digital projection unit and two cameras in a stereo arrangement, whereby both are battery powered. The data transfer to a base station will be done via WLAN. This gives the possibility to use the system in complicate, remote measurement situations, which are typical in archaeology and architecture. In the measurement procedure the sensor will be hand-held by the user, illuminating the object with a sequence of less than 10 fringe patterns, within a time below 200 ms. This short sequence duration was achieved by a new approach, which combines the epipolar constraint with robust phase correlation utilizing a pre-calibrated sensor head, containing two cameras and a digital fringe projector. Furthermore, the system can be utilized to acquire the all around shape of objects by using the phasogrammetric approach with virtual land marks introduced by the authors^{1, 2}. This way no matching procedures or markers are necessary for the registration of multiple views, which makes the system very flexible in accomplishing different measurement tasks. The realized measurement field is approx. 100 mm up to 400 mm in diameter. The mobile character makes the measurement system useful for a wide range of applications in arts, architecture, archaeology and criminology, which will be shown in the paper.

We present a methodology, based on 3D scanned digital models, for measurement and monitoring wood deformations, caused by weather changes, in the trees of the fossilized Dunarobba forest. The Dunarobba forest, located in the central part of Italy, was discovered recently after some excavations to dig clay for bricks manufacturing. The removal of the clay mass exposed the wood to the weather conditions, initiating a process of degradation. Different conservation methodologies have been proposed and the choice of the best fitting one has to be validated by means of an objective and measurable methodology. Monitoring the geometric variation of the wood trunks trough comparison of periodic 3D scanning campaign will be used to evaluate the current degradation rate and assess the effectiveness of the proposed conservation techniques.

The quantitative morphological analysis of a painting surface allows to evidence form defects and to study, thus, their influence on the stability of the paint and preparatory layers, as well as of the support. Therefore a three-dimensional survey can be very useful in planning the restoration intervention of a painting. In this work we present the results of the surface analysis carried out on the painting "Ultima Cena" by Giorgio Vasari. This panel painting is severely affected by paint film wrinkling produced as a consequence of the flood that occurred in Florence in 1966. Our analysis, accomplished to quantify the lengthening of the paint layer with respect to the one of the support in order to plan the restoration intervention, was performed on 25 profiles separated each by 10 cm in order to cover the whole painting surface. A data analysis, based on morphological filtering named "Rolling Ball" transformation, was used to evaluate the length difference between the paint layer and the panel support along each profile.

In this paper, we are interested in accurate acquisition and modeling of flint artefacts. Archaeologists needs accurate geometry measurements to refine their understanding of the flint artefacts manufacturing process. Current techniques require several operations. First, a copy of a flint artefact is reproduced. The copy is then sliced. A picture is taken for each slice. Eventually, geometric information is manually determined from the pictures. Such a technique is very time consuming, and the processing applied to the original, as well as the reproduced object, induces several measurement errors (prototyping approximations, slicing, image acquisition, and measurement). By using 3D scanners, we significantly reduce the number of operations related to data acquisition and completely suppress the prototyping step to obtain an accurate 3D model. The 3D models are segmented into sliced parts that are then analyzed. Each slice is then automatically fitted by mathematical representation. Such a representation offers several interesting properties: geometric features can be characterized (e.g. shapes, curvature, sharp edges, etc), and a shape of the original piece of stone can be extrapolated. The contributions of this paper are an acquisition technique using 3D scanners that strongly reduces human intervention, acquisition time and measurement errors, and the representation of flint artefacts as mathematical 2D sections that enable accurate analysis.

Today, terrestrial laser scanning has been a frequently used methodology for the documentation of historical buildings and cultural heritages. The historical peninsula region is the documentation of historical buildings and cover approximately 1500 ha. Terrestrial laser scanning and close range image photogrammetry techniques are integrated to each other to create a 3D urban model of Istanbul including the most important landmarks and the buildings reflecting the most brilliant areas of Byzantine and Ottoman Empires.

The propagation of polarized laser beams in turbid water is a subject of relevant interest in the field of underwater quantitative visualization with active sensors like amplitude modulated laser systems. In such devices, target range determination is based on the measurement of the phase difference ΔΦ between the fraction of the amplitude modulated laser beam reflected by the target and a reference signal. As water turbidity increases, the laser radiation backscattered from the water column shined by the sounding laser beam gives rise to an optical background with detrimental effects on the accuracy of range measurement. In this paper we analyze the possibility to increase the apparatus accuracy with a polarimetric technique based on the adoption of polarized laser radiation and polarization selective detection scheme for improving the underwater imaging of real scenes (e.g. archaeological sites). The method fully takes advantages of the different polarization properties of the laser radiation backscattered by turbid water and of the Lambertian component diffusively reflected by the target as described by the associated Mueller matrices. Measurements have been performed by adopting both a co-polarized and cross-polarized detection scheme with linearly and circularly polarized laser radiation. Various degrees of turbidity were realized by adding, as diffusive element, skim milk to water in order to obtain different scattering conditions. The effect of the transition from Rayleigh to Mie scattering regime on phase accuracy determination has been investigated together with the role played by high order scatterings as the medium approaches the optical thickness condition.

We present the recent results obtained by a system which measures both 3D shape and multispectral texture of artistic and architectural cultural assets. The system consists on a rangefinder device which acquires the range and a visible scanning spectrograph for colour texture analysis. This technique is applied to the acquisition of the cycle of Stories of Maria, a frescoed lateral chapel painted by Girolamo Tessari in 1523-1526 located in the church of S. Francesco in Padua (Italy).

At the ENEA TRIGA research reactor (Casaccia Research Center, Rome), an equipment is available for neutron radiography applications, including radiographic image digitalization system based on a CCD camera and rotating unit for tomography applications. After the neutron-light conversion stage, the image acquisition is performed with an assembly of mirror, lenses and CCD connected to a personal computer located in the reactor room. A software package elaborates the image set performing a filtered back projection tomographic 3-D reconstruction generating a DICOM formatted data set. For visualizing 3D neutron tomography, the Perspecta Spatial 3D Visualization Platform, developed by Actuality Systems, Inc. was used.

A portable fluorescence multi-spectral imaging system was developed and applied to the analysis of artistic surfaces. The imaging apparatus exploits UV lamps for excitation and a liquid crystal tunable filter coupled to a low-noise CCD as the image detector. A sequence of images is acquired by sweeping the transmission band of the filter in order to slice the fluorescence emission in many narrow bands within the visible region of the e.m. spectrum. In this way, the fluorescence spectrum is recorded in each point of the analyzed area. The main features of the system will be discussed, together with its application to the analysis of the fluorescence properties of binders and pigment typically used in mural paintings. Finally, the study of the conservation of Renaissance frescoes recently restored will be presented.

Laser-induced fluorescence for remote imaging of historical monuments is an established technique, which in this work has been used in measurement campaigns at the Coliseum and the Baptistery of San Giovanni in Laterano in Rome, Italy. The results presented here are examples that show that biodeteriogens can be monitored and that materials can be identified. Also, cleaned and soiled areas on the stone can be localized and differences between soiling can be found, which may be useful in the sustainable conservation for mapping and evaluation.

A non-destructive technique giving an early diagnosis of glass degradation is presented here. It allows to implement a new sol-gel method that stops further deterioration of the glass and avoid the classical removing of crusts. Reflectance spectroscopy in the visible range is used with a portable fiber-optics spectrophotometer in a back-scattered configuration and underlines very fine levels of glass alteration. Quantitative validations on reference samples are first presented. The reference glasses have varying amounts of lead and have been damaged using a defined and controlled degradation process. The deterioration begins by an increase in the roughness of the upper surface, quantified by an upward vertical translation of the reflectance spectra. For glasses containing an important amount of lead, it is followed by a decrease in this roughness and the apparition of periodic oscillations of spectrum, due to interferences inside a transparent layer created by the loss of lead. The analysis of these oscillations leads to the quantification of the thickness of the altered layer and to its evolution with the degradation. These results have been validated by RBS analysis. The same measurements have been implemented on archeological samples that have been damaged by naturally occurring reactions while being buried in soil. Comparisons of features and oscillations of the reflectance spectra discriminate non-, weakly and strongly altered areas of the glasses, no matter the amount of lead in the samples.

The aim of this paper is to investigate the influence of gamma irradiation process on the colour of painted wood panels. Insects and micro-organisms are frequently identified enemies of cultural objects from museums and archives. Based on its biocide effect, gamma radiation could be used for decontamination and conservation purposes. Important advantages can be mentioned in its favour: no toxic or radioactive residues remained in the treated item; large amount of objects can be treated quickly; excellent reliability; attractive cost. In case of emergency radiation treatment in industrial facilities is probably the only method that can be used. There is also a potential side-effect. Interaction of gamma rays with any substance may change its chemical and physical properties. The change is proportional with the irradiation dose. In the case of paintings, eventually colour changes have to be evaluated. Such an approach actually establishes irradiation treatment limitations. A portable integrating sphere spectrophotometer was used for colour measurements. The results of colour analysis before and after the radiation treatment of the painted wood panels are reported and discussed.

Bayesian Classification methods can be applied to images of watercolour paintings in order to characterize blue and green pigments used in these paintings. Pigments found in watercolour paintings are semi-transparent materials and their analysis provides important information on the date, the painter, the place of the production of watercolour paintings and generally on the authenticity of these works of art. However, watercolour pigments are difficult to characterize because their intensity depends on the amount of liquid spread during painting and the reflective properties of the underlying support. The method describedin this paper is non-destructive, non invasive, does not involve sampling and can be applied in situ. The methodology is based on the photometric properties of pigments and produce computational models which classify diverse types of pigments found in watercolour paintings. These pigments are photographed in the visible and infrared area of electromagnetic spectrum and models based on statistical characteristics of intensity values using a mixture of Gaussian functions are created. Finally the pigments are classified using a Bayesian classification algorithm to process the generate models.

It is well known that artworks exposed in museums or galleries can be damaged by infrared and ultraviolet radiation. Moreover, if not properly protected, these precious paintings or sculptures can be also damaged by vandalism acts. Coated glasses can actually deal with both these problems. They can also improve the artworks viewing if an antireflection feature is realized. However such optical coatings should not affect color viewing. In this study we describe a new prototype of coating and investigate, by mean of psychophysical experiments, how it affects color perception relative to uncoated glass as well as commercial coating products made up by many coating layers (up to 50). Our results show that color discrimination in the condition in which colors were viewed through our coating prototype turned out in being better than in the experimental condition in which uncoated glass was used and surprisingly at least as efficient as the more expensive commercial coated glasses.

Application of Laser Induced Breakdown Spectroscopy (LIBS) for investigation of chemical constitution and stratigraphy of artworks, and metallic objects with multilayer structures is described in the paper. Physical phenomena accompanying LIBS investigations, especially temporal evolution and spectral lines broadening are described. Operational characteristics of experimental equipment are shown. Results obtained with use of two different echelle spectrometers are compared. Pigments used in oil paintings are analyzed and analysis results are presented. Experimental results of measurements of various objects like paintings, sculptures and artifacts are shown. Works on dating of investigated paintings are described.

An influence of some physical phenomena disturbing correct interpretation of LIBS spectra is described in the paper. The following phenomena were investigated: a way of laser beam focusing (power density), laser spark in air, spectral line broadening, apparatus efficiency and resolution, and an influence of those factors on LIBS spectra as well. They are particularly important for quantitative LIBS measurements. The presented measurement results clearly show that the correct elemental identification plays a significant role in artworks dating [5].

This is an introductory paper of a recent EC project dealing with research in cultural heritage and aiming to communicate new fields of application for optical metrology techniques. The project is in its initial state and more conclusive information is expected to be available at the time of the perspective conference. Nowadays safety, ethical, economical and security issues as well as the increase demand for loaning of art objects for exhibitions in transit, are forcing the Conservation Community to undertake strong initiatives and actions against various types of mistreatment, damage or fraud, during transportation of movable Cultural Heritage. Therefore the interest directs to the development of innovative methodologies and instrumentation to respond to critical aspects of increased importance in cultural heritage preservation, among which of prior consideration are: to secure proper treatment, assess probable damage, fight fraud actions in transportation.

Monuments are continuously submitted to external events like water infiltration or condensation, temperature variation, soil instability, that lead to internal damage of the structure itself as well as of its surfaces. Wall paintings are then submitted to stresses that may cause cracks, internal de-lamination of the plaster or de-bonding between canvas and plaster. In the frame of the restoration of the "galerie des glaces" in the "château de Versailles", TV-Holography and IR Thermography have been used to investigate the wall paintings of the vault. The surfaces to control were either direct paintings on the plaster or paintings on canvas backed on the plaster. IR Thermography for art work and in particular for wall paintings has only recently been used. The technique allows to record transient temperature maps, when slightly heating the surface during a short time. Then, nonhomogeneities in the conductive heat transfer are related to de-bonding or de-lamination. The time parameter gives information on the depth of the defect. A calibration procedure has to be carried out to ensure reliable defect detection. Speckle interferometry is a Non Destructive Testing technique that is currently used in industry. For the wall paintings, we have used TV-Holography associated with a continuous wave laser. The technique allows, 13 metres away from the surface, to detect parts of the paintings that were vibrating due to an acoustic excitation. The control processes based on these two technologies is detailed as well as the results obtained and a comparison with manual investigation is done.

The deterioration of cultural heritage is of major concern for gallery conditions and loan considerations worldwide. Artwork deterioration may increase during transportation and exhibitions or mishandling. Decisions about gallery conditions and loan requirements shall need reconsideration if findings based on artworks undergoing these procedures prove that impose catastrophic dimensional fluctuations. In this context, non interacting and non contact methods are useful in order to monitor the continuous changes in the monitored artwork. The presented paper refers to this application of high importance for the preservation of cultural heritage and forms part of the European project Multiencode (006427 SSPI). Holography techniques, in either optical and digital acquisition, are known to allow full field observation of object point's displacement. In addition to the importance provided by the techniques of revealing hidden discontinuities within an object, the procedures that have been developed which can be used to visualize and study deformations following environmentally induced alterations are similarly important. The interferometric formation which results in fringe patterns which correspond to hidden defects can be used as a key-indicator to control and monitor accidental or intentional interventions which may effect an object and hence result in an alteration of the originally-revealed fringe pattern information. Thus, in this paper the specific steps taken to develop an Impact Assessment Procedure for the assessment and evaluation of the fringe pattern alterations deduced by the implementation of a Digital Holographic Speckle Pattern Interferometry(DHSPI) system is presented and examples of the application are given.

This is one of a series of papers submitted by the Multi-Encode Project consortium (006427 (SSPI)). Shearography, a full-field speckle interferometry technique, is applied to the investigation of movable cultural heritage. For this project a portable shearography sensor was developed, with conventional sensor hardware supported by novel algorithms and instrument control software. The sensor has been used for an extensive measurement program, the purpose of which is to develop an Impact Assessment Procedure; this is to determine the capabilities of a shearography sensor in this measurement application. Data from the sensor, which shows the location of defects in the artwork, is stored in a database for future analysis and comparison. The particular advantages identified for incorporating shearography in a multi-functional sensor are the ability to measure unstable objects, such as gently vibrating canvas paintings, adjustable interferometric sensitivity and a different sensitivity parameter (displacement gradient) to the other sensors investigated. This work will assist in fulfilling the aims of the project, the detection of signature features for security purposes and the study of changes in artwork for conservation purposes.

A new, fast and easy process for nanostructuring of hard surfaces is currently being developed: explosive embossing. The Institute for measurement and control engineering (IMR) of the Leibniz-Universität Hannover and the Fraunhofer-Institute for Chemical Technology (ICT) are currently presiding over the project¹ which deals with the practicability of explosive embossing for nanostructures such as holographic structures. Within this project the IMR is concerned with the digital creation of holographic data and the numerical simulation and the evaluation of the transfer characteristics of the explosive-embossing-process.

This paper is one of a series submitted by the Multi-Encode Project consortium and covers the development of holographic interferometry with dynamic photorefractive crystals. The aim of the first phase of the project is to assess the existing techniques for detection of signatures in various types of artworks. The trademark of our technique is a very high resolution in the fringe pattern. We will show the potentiality of our technique for the present application.

A variety of scientific investigation methods applied to paintings are, by now, an integral part of the repair process, both to plan the restoration intervention and to monitor its various phases. Optical techniques are widely diffused and extremely well received in the field of painting diagnostics because of their effectiveness and safety. Among them infrared reflectography is traditionally employed in non-destructive diagnostics of ancient paintings to reveal features underlying the pictorial layer thanks to transparency characteristics to NIR radiation of the materials composing the paints. High-resolution reflectography was introduced in the 90s at the Istituto Nazionale di Ottica Applicata, where a prototype of an innovative scanner was developed, working in the 900-1700 nm spectral range. This technique was recently improved with the introduction of an optical head, able to acquire simultaneously the reflectogram and the color image, perfectly superimposing. In this work we present a scanning device for multi-spectral IR reflectography, based on contact-less and single-point measurement of the reflectance of painted surfaces. The back-scattered radiation is focused on square-shaped fiber bundle that carries the light to an array of 14 photodiodes equipped with pass-band filters so to cover the NIR spectral range from 800 to 2500 nm

We present a proto-type portable remote multispectral imaging system, PRISMS (Portable Remote Imaging System for Multispectral Scanning), that is light-weight, flexible and without any cumbersome mechanical structure for in situ high resolution colour and spectral imaging of large and inaccessible paintings such as wall paintings. This is the first instrument to be able to image paintings at inaccessible heights in situ from ground level to produce not only high resolution colour images but also multispectral images.

In this paper we present a scanning device for multispectral imaging of paintings in the 380-800 nm spectral region; the system is based on a spectrophotometer for contact-less single-point measurements of the spectral reflectance with 10 nm resolution. Two orthogonal XY translation stages allow to scan up to 1,5 m² with spatial resolution up to 8 dots/mm. As an application we present the results of the measurements carried out on Ritratto Trivulzio by Antonello da Messina and Madonna in gloria tra Santi by Andrea Mantegna. Besides spectra comparison also multivariate image analyses (MIA) have been performed by considering the multi-spectral images as three-way data set. In order to point out the slight spectral differences of two areas of a painting we analyzed its multispectral data cube by means of the Principal Component Analysis (PCA) and the K-Nearest-Neighbouring Cluster Analysis (KNN).

The interaction of materials with the atmosphere has recently received increased attention. Although the interaction between atmosphere chemistry, weathering and pollutants deposition is complex, there is a need for measuring the surface materials lost through weathering and acid rain by art objects. In fact, data regarding material response to different conditions can be used to predict long-term trends in degradation as well as to assess deterioration process parameters. Conventional inspection techniques, such as ultrasonic measurements or X-ray radiography, can be time-consuming and/or expensive. In principle, methods to monitor artwork corrosion should have the following features: non-contact nature, fast and inexpensive operations, good sensitivity. In this paper an investigation on detection and monitoring of artwork corrosion by infrared thermography and optical techniques is carried out. In IR thermography, material loss is related to thermal contrast, which is defined as a suitable normalization of temperature differences on the specimen. Optical techniques basically rely on optical contouring, which leads to a 3D map of the surface. Experimental results obtained using simple inversion procedure for IR data are compared with optical results.

During the last decade, laser ablation process has been just utilized for removal of encrustation at works of art and architectural historical objects. This technique utilizes substantial difference in laser radiation absorption coefficients of encrustation and substrate. In the paper authors present next architectural object cleaned with pulse laser radiation - limestone epitaph and stalls of King Batory's Chapel at Wawel Castle in Cracow, Poland. Experimental results include measurements and optimization of laser fluency in dependence on radiation wavelength of Nd:YAG laser with harmonic generation as well as colorimetric (hue) measurements of objects before, during and after laser cleaning.

The main aim of laser cleaning is removal of encrustation without damage of original artwork substrate material. Art object are often made of fragile and breakage vulnerable materials, for which laser cleaning is an irreplaceable technique. The same applies to figures and sculptures made of different kinds of bones, so it is needed to determine damage threshold values of laser fluency. The paper, therefore, presents the results of investigations of pulse laser radiation interaction with bovine bones, ivory and bear tusk, utilizing different harmonic wavelengths of Nd:YAG laser in a wide range of fluences. It includes fundamental wavelength of 1064 nm with maximum energy of 500 mJ and harmonics: 532 nm (250 mJ) and 355 nm (90 mJ), generated by ReNOVALaser 5 system. Laser fluency has been controlled by means of direct energy variations or by radiation focusing at the object (from 8 mm to 300 &mgr;m), using constant pulse duration of 15 ns. Exact determination of bones threshold damage was based on microscopic investigation of the results of laser pulse irradiation.

The limiting performance characteristics of con-focal chromatic aberration displacement sensors are angular tolerance and the gauge range over which an output is provided. The sensor selected in this study is used to measure groove profiles in early recorded surfaces. The sensor is used in a 3 dimensional cylinder scanning system for the measurement of wax cylinder recordings, where the 3 dimensional data is used to create a map of the measured surface for archival purposes. The generation of the map allows the sound recorded on the surface to be decoded without physical contact to the surface. It has been shown in a previous study that data resolution of 10-20nm are required for this application, and that the relationship between the data output and the surface incline is critical to system performance. To understand the relationship with surface slope the sensor is used here in a study of the measurement of calibration ball surfaces, and follows a previous study on machined grooves with known angular properties. In this study a range of calibration spherical surfaces are used to investigate the relationship between the sensor output and measurement parameters, including the distance between the sensor optical head and the surface. A linear least squares method is used to evaluate the 3D radius of the measured surfaces, and this is used as a parameter to evaluate the systematic errors. The results show that there is a low level of systematic form error typically below 1&mgr;m, but that this error has a significant impact on the evaluation of the radius. Recommendations are made on methods for optimisation of sensor performance.

The design and experimental method for the use of a novel instrument for lightfastness measurements on artwork is presented. The new microfadometer design offers increased durability and portability over the previous, published design, broadening the scope of locations at which data can be acquired. This reduces the need for art handling or transportation in order to gain evidence-based risk assessments for the display of light-sensitive artworks. The instrument focuses a stabilized high powered xenon lamp to a spot 0.25 millimeters (FWHM) while simultaneously monitoring color change. This makes it possible to identify pigments and determine the lightfastness of materials effectively and non-destructively. With 2.59mW or 0.82 lumens (1.7 x10⁷ lux for a 0.25mm focused spot) the instrument is capable of fading Blue Wool 1 to a measured 11 ΔE_ab value (using CIE standard illuminant D65) in 15 minutes. The temperature increase created by focused radiation was measured to be 3 to 4°C above room temperature. The system was stable within 0.12 ΔE_ab over 1 hour and 0.31 ΔE_ab over 7 hours. A safety evaluation of the technique is discussed which concludes that some caution should be employed when fading smooth, uniform areas of artworks. The instrument can also incorporate a linear variable filter. This enables the researcher to identify the active wavebands that cause certain degradation reactions and determine the degree of wavelength dependence of fading. Some preliminary results of fading experiments on Prussian blue samples from the paint box of J. M. W Turner (1755-1851) are presented.

Polarised-light (or petrographic) microscopy has been widely applied to heritage materials to assess composition and diagnose damage. However, instead, this paper focuses on the petrographic investigation of brick and mortar technologies for the production of quality repair materials compatible with their adjacent fabrics. Furthermore, the paper relates production technologies to the physical properties of the materials fabricated, and thus their final quality and durability. According to Cesare Brandi´s theory of compatibility (the 20th century architect on whose work modern conservation theory and practice are largely based) existing historic materials should be replaced with their equivalent. This paper demonstrates that polarised-light microscopy provides data on the origin and nature of raw materials, and processing parameters such as blending, mixing, firing, calcination and slaking, and how these relate to the quality of the final product. In addition, this paper highlights the importance of production technologies as these directly impact the physical properties of the materials fabricated and thus determine their final quality and durability. In this context, the paper investigates mortar calcination and slaking, two important operations in the manufacture of building limes that govern the reactivity, shrinkage and water retention of a lime binder which will impact mortar's properties such as workability, plasticity and carbonation speed, and these in turn will determine the ease of execution, durability and strength of a lime mortar. Petrographic analysis also provides evidence of ceramic technology including identification of local or foreign production and processing parameters such as sieving, blending, mixing and firing. A petrographic study of the ceramic matrix coupled to the diagnosis of mineral phases formed during firing allows to quantify sintering and vitrification and thus determine firing temperatures. Finally, certain features of the raw clay such as the grading and the amount and nature of the non-plastic material inform, not only on the raw material's origin, but also impact the physical properties of the ceramic ware.