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In this paper an overview of recent applications of mid-wave infrared imaging techniques to the study of books is presented. Studies performed by thermography and mid-wave infrared reflectography a...

The study of bronze statues obtained by the lost-wax casting method results of particular relevance from the artistic and historical points of view. In particular, the characterization of structural and subsurface elements of bronzes is very useful to gather insight concerning their preservation state and manufacturing process. For these purposes, infrared thermography has been successfully employed to investigate different kind of items of artistic bronzes, such as repairs, defects and inserts, providing also the possibility to perform the depth-resolved study of the observed subsurface features thanks to the possibility it also provides to evaluate the thermal transport properties of the investigated materials. In this work, the experimental configurations and the capabilities of such a technique have been reviewed. The state of the art of the results obtained by infrared thermography for the analysis of artistic bronzes is presented. It is thus shown that infrared thermography can be nowadays considered as a reliable and consolidated technique to map in a non-destructive way a wide spectrum of features of bronzes.

Library material, and thus parchment, is frequently subjected to bio-deterioration processes caused by microorganisms. Fungi and bacteria cause alterations in the parchment inducing, in some cases, even the partial detachments of the surface layer and the loss of any text present on it. An important contribution to disinfection of the cultural heritage artefacts is given by the use of ionizing radiation. In this work, a preliminary study on the applicability of X-ray radiation as treatment for bio-deterioration removal is proposed. The results on the microbial growth after different irradiation treatments are shown in order to detect the dose protocol for the bio-degradation removal. Furthermore, the evaluation of the irradiation effects on the parchment microstructure is presented in order to define the applicability of the method on parchment artefacts.

© 2019 Elsevier B.V. The collagen denaturation process in several artificially aged modern parchment samples were studied by combining Adiabatic Scanning Calorimetry and Light Transmission Analysis investigations. It was found that the calorimetric evaluations enabled not only to confirm the previously reported specific heat results concerning the collagen denaturation peaks, but also to identify a novel broad feature most likely associated with additional transformations occurring once denaturation takes place. Moreover, the combination of the investigations by the two adopted techniques allowed to validate the Light Transmission Analysis as a novel simple method capable of recording the entire collagen denaturation temperature path of the analyzed samples. Finally, the polarization microscopy imaging, performed simultaneously with the optical transmission characterization, enabled to perform a direct correlation of the morphology changes of the parchment with the different stages of the collagen denaturation. ispartof: Thermochimica Acta vol:676 pages:263-270 status: published

In the analysis of complex stratigraphical structures like painted artefact, infrared (IR) techniques can provide precious information about elements hidden under superficial layers of the artwork, such as pictorial features and structural defects. This paper presents a novel complementary use of reflectographic and thermographic techniques for the survey of three baroque paintings, preserved at the Chigi Palace in Ariccia (Italy). First, the IR-ITR laser scanner prototype has been used for the preliminary and remote near-IR reflectographic survey of the areas where the canvas was located. The resulting map was then used for planning the thermographic and mid-IR reflectographic studies, focusing the analyses on the most interesting areas of one of the paintings, called “La Primavera”. The combination of the three imaging techniques revealed several details not visible by the naked eye, such as restored lacunas and pentimenti, demonstrating the validity and complementarity of the proposed combined methodologies.

In this work, the capability of Infrared Thermography to characterize in a non-destructive way the main features of illuminated manuscripts has been assessed. It has been shown how this technique can be exploited for a general investigation of the book materials, structure and decorative apparatus, providing information on the manufacturing method, the preservation state and the changes operated throughout the history of the artefact. The used thermographic approach provided infrared images which show also the non-visible surface and subsurface elements that constitute the illumination metastructure, intended as the structure of the entire pictorial system. A number of aspects, like the verification of the adhesion state of the gold leaf, the recovery of the pentimenti, the detection of metal foil residues and the characterization of the damage produced by fungi and bacteria have been studied. For each of the investigated features an interpretative model accounting for the infrared emission processes responsible of the thermogram generation has been proposed. Moreover, for every studied aspect, it has been shown how, based on the thermographic results, other complementary analyses can be directed like Infrared Reflectography, Scanning Electron Microscopy, X-ray Fluorescence and the Energy Dispersion Spectroscopy. The effectiveness of the proposed approach has been tested in the study of Liber Regulae S. Spiritus de Saxia, a 14th century illuminated manuscript of great historical importance and artistic value, since the wide spectrum of the employed materials and the complexity of the structural changes operated during its history by extensive restoration make it a valid test-bed.

In this paper a method is presented based on the use of active infrared thermography for the detection of subsurface graphical features in artworks. A theoretical model for the thermographic signal describing the physical mechanisms which allow the identification of the buried features has been proposed and thereafter it has been applied to the analysis of the results obtained on specifically made test samples. It is shown that the proposed model predictions adequately describe the experimental results obtained on the test samples. A comparative analysis between the proposed technique and infrared reflectography is also presented. The comparison shows that active thermography can be more effective in the detection of features buried below infrared translucent layers and, in addition, that it can provide information about the depth of the detected features, particularly in highly IR diffusing materials.

Over the last few years, there has been an increasing interest in the application of photothermal techniques to the investigation of cultural heritage. Thanks to their peculiar ability of depth-resolving the position of subsurface features, these techniques are in fact well suited for a nondestructive analysis of multi-layer structures such as the one typical of artwork. In addition, the recent availability of highly developed instrumentation makes it possible to effectively carry out in situ investigations into different kinds of artwork. Such circumstances have created new opportunities in both theoretical and experimental research whose development is still in progress. In this work, we report an overview of the results that have been obtained on several kinds of artwork and of further developments that can be used to improve the effectiveness of the application of photothermal techniques to this field.

In this paper, infrared thermography is applied to the quantitative characterization of optically semi-transparent media by using a newly introduced mathematical model. The method is specifically aimed to the detection and evaluations in graphic features buried beneath the surface of some particular kind of cultural heritage artefacts, such as books and documents. A numerical approach based on the finite element method, is proposed for solving the model equations. The computed thermographic signal depends on different inspected material physical properties, which have been selectively evaluated by comparing the theoretical results with the experimental ones in specifically designed test samples. Thereafter, the model is applied to the analysis of the results obtained in the case of graphic elements buried within samples constituted by the same previously characterized materials.

In this paper, a new method based on the use of infrared thermography is proposed for the characterization of repairs and inserted parts on ancient bronzes. In particular, the quality of the contact between different kind of insertions and the main body of bronze statues is investigated by analysing the heat conduction process occurring across the interface between them. The thermographic results have been used to establish the nature of these inserted elements and the way they have been coupled to the main body of the statue during and after the manufacturing process. A model for the heat conduction based on the numerical finite elements method has been applied to compare the obtained results to the theoretical predictions. Measurements have been first carried out on test samples and then in the field on the Boxer at Rest (Museo Nazionale Romano in Rome), a masterpiece of the Greek Statuary, which contains a large variety of inserted items and repairs which are typical of the manufacturing process of bronze artefacts in general.

In this paper, the thermographic results obtained by studying some masterpieces of the bronze statuary of Rome are presented. More specifically, a quantitative approach has been adopted in the investigation of the Capitoline She Wolf, hosted in the Musei Capitolini, and of the Boxer at Rest and the Hellenistic Prince belonging to the collection of the Museo Nazionale Romano. The obtained results provided data useful to characterize the properties of the bronze alloy and several subsurface features of the statue, such as casting faults and patches. In particular, the interface between different kind of patches and the main body of the statue has been investigated in order to determine the way they were applied. Moreover, the thermal diffusivity of the alloy of the Capitoline She Wolf has been evaluated and quantitative investigations have been carried out in order to determine the depth of some features, such as the cavities originating from air bubbles in the casting melt.

Pulsed infrared thermography was applied to the analysis of the Capitoline She Wolf bronze statue, in the collection of the Musei Capitolini in Rome. We show how it can be used to study the bronze alloy properties and several subsurface and structural features of the statue such as casting faults and repairs providing information useful to recover the steps of the manufacturing process. In particular, the thermal diffusivity of the alloy was determined and quantitative evaluations were carried out concerning the thickness of the bronze in various parts of the statue, the depth of cavities originating from air bubbles in the casting melt and the profile of the contact area of some patches applied to mend gaps left after the casting process. Finally the obtained thermal diffusivity value was discussed in relation to the actual bronze composition of the She Wolf statue and it was shown to be consistent with the trend of values expected for different copper alloy compositions.

The infrared (IR) emissivity of a set of polymeric fibers composed of randomly oriented carbon nanotubes dispersed into a poly(ethylene terephthalate) matrix host was investigated. Samples containing different amounts of carbon nanotubes in the range between 1 and 10 wt% were analyzed. The effects of the included carbon nanotubes on electrical and morphological properties were studied by means of electric conductance, scanning electron micrography and white light interferometry investigations, respectively. The emissivity was characterized in the 3.5–5.1 μm spectral range by using the infrared thermography technique under heating regime. To analyze the obtained results, a theoretical model based on the Maxwell Garnett theory has been proposed. A percolation effect in the electrical conductance and a gradual increase of the emissivity has been observed, respectively with increasing carbon nanotubes content. In particular, morphological investigations showed the emerging surface roughness when carbon nanotubes are added to the polymeric matrix which may further contribute to the increase of the emissivity value. On the basis of the obtained results, it can be concluded that the investigated composite fibers have the potential to develop new materials enabling both high IR emission and large electrical conduction.

In this work we investigate various aspects of the finishing process in ancient bronze sculptures by means of active infrared thermography (IRT). Active IRT provides information on surface and sub-surface features of the investigated artefact, by analysing the heat diffusion process induced within the sample by appropriate thermal stimulations usually produced by absorption of light emitted by different sources. The aim of this research is, in particular, to investigate the processing of bronze surfaces, revealing repairs like plugs, fillings, local castings and concealed marks.

In this paper, an overview of the recent applications of pulsed infrared thermography is presented. Pulsed infrared thermography, which provides stratigraphic information by analyzing the heat diffusion process within the sample after a thermal perturbation, is applied to the investigation of different kinds of cultural heritage artefacts. In particular, it is used to analyze repairs, decorative elements, and casting faults on bronzes, to detect texts hidden or damaged in ancient books/documents, and to characterize paint decorations. Moreover, the integration of pulsed infrared thermography and three-dimensional shape recording methods is proposed in order to provide a three-dimensional representation of the thermographic results. Finally, it is shown how the obtained thermographic results may be crucial from the historical and artistic points of view for understanding the modus operandi of a specific artist and/or of a workshop and for reconstructing the manufacturing process of the analyzed artefacts.