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Sara Croci, Leila Es Sebar, Caterina Gori, Leonardo Iannucci, Emma Angelini, Sabrina Grassini
Preventive conservation plan for a group of bronze sculptures from the Gori Art Collection

This paper deals with a multi-analytical and long-term in-situ monitoring campaign for evaluating the state of conservation of some outdoor contemporary bronze sculptures of the environmental Gori Collection, at the Villa Fattoria di Celle, located in the municipality of Santomato, Pistoia, Italy. Digital twins of the Cavaliere and of one of the thirty-three figures of Katharsis have been made by means of 3D photogrammetry in order to characterize the artworks. On the same sculptures, the chemical composition of the corrosion patinas has been determined by Raman spectroscopy. Moreover, the protective effectiveness of the corrosion products layer has been assessed by means of electrochemical impedance spectroscopy. The analytical data obtained in the monitoring campaign, still in progress, are discussed as a function of the exposure time to outdoor environment of the works of art.

Jose Santiago Pozo Antonio, Teresa Rivas, Pablo Barreiro, Vera Caetano, Fernando Carrera, Lara Bacelar Alves
In situ characterization of prehistoric rock paintings: the Côa Valley (Portugal)

This paper draws on the study of the prehistoric art complex of the Côa Valley in north-east Portugal. Its main goal was to apply an in situ methodology for characterising prehistoric rock paintings. Thus, panels exhibiting red motifs were analysed by colour spectrophotometry and portable Raman spectroscopy. Motifs, crusts developed on the decorated surfaces and the backdrop stones have been analysed. Motifs from four sites within this archaeological complex were grouped considering their CIELAB and CIELCH parameters L*, a*, b*, C*ab and h due to their different colours. Raman spectroscopy showed that hematite is the predominant pigment in the motifs. Goethite, quartz and feldspars have also been identified in some motifs; their presence may reveal the use of ochre but may also come from the backdrop.

Beatrice Calosso, Marialuisa Mongelli, Sara Pettisano, Samuele Pierattini
Digitalization of Bernini’s drawing Tondo depicting St. Joseph with the baby Jesus. Increasing knowledge and monitoring surface cracks

The main goal of the study carried out by ENEA described in this paper has been to create a three-dimensional virtual model of a sanguine drawing by Bernini, useful in the definition of the conservation status of the artwork and in facilitating the medium and long-term monitoring of the damage, highlighted and measured using Photogrammetry technique. The show up details will help further in-depth analysis to better know the historical, material, and iconographic characteristics of this drawing, crossing scientific data with archival data.

Giorgio Saverio Senesi, Sara Mattiello, Vincenzo Palleschi, Bruno Cocciaro, Girolamo Fiorentino, Olga De Pascale
Handheld laser-induced breakdown spectroscopy, portable energy dispersive X-ray fluorescence spectroscopy and Graph Clustering applied to the identification and inner stratigraphy of archaeological metallic artifacts

Two advanced analytical techniques, i.e., non-destructive portable Energy Dispersive X-Ray Fluorescence (pED-XRF) and micro-destructive handheld laser-induced breakdown spectroscopy (hLIBS) supported by a Graph Clustering method have been applied to identify the elemental composition and inner stratigraphy of five copper and two iron alloy artifacts originated from various ancient graves in the area of Minervino Murge (Barletta, Andria, Trani - BAT), Apulia, Italy. The main elements detected by both techniques were Cu, Sn and Pb in copper alloys and Fe with minor amounts of Cu and Pb in iron ones, together with Al, Ca, Si, Mg and K feasibly originated from soil contamination, and the trace elements Sb and Zn. The pED-XRF spectra were distributed in three distinct clusters, whereas LIBS spectra were classified in four clusters.
These instruments have proved to be able to provide reproducible quantitative data in agreement with literature data, thus representing powerful means in outdoor archaeology and archaeometry campaigns.

Agnese De Carlo, Valerio Graziani, Paolo Branchini, Luca Tortora
Monoazo and Isoindoline Yellow reactivity in presence of Pb, Ti, Zn-based white substrates

This work explores the effects of accelerated aging conditions on two yellow synthetic organic pigments with good light fastness: PY 1 and PY 139 also known as Hansa Yellow G (or Monoazo yellow) and Isoindoline Yellow, respectively. The reactivity of PY 1 and PY 139 in presence of reactive inorganic whites such as basic lead carbonate, titanium oxide, and zinc oxide was investigated. The accelerated aging process was achieved through UV irradiation in a home-made climatic chamber for a set of bilayer paint mock-ups. Bilayered samples were realized to simulate the painting technique of superimposing multiple layers of thinly applied paint. Colorimetry, Fourier-Transform Infrared Spectroscopy, and Photoluminescence Spectroscopy were adopted to reveal physico-chemical changes occurred in such samples.

Eleonora Marconi, Luca Tortora
Synthesis of titania nanoparticles in W/O microemulsion: moving the production toward a green approach

In this work, we report an easy, fast, reproducible, and low-temperature microemulsion procedure for the large-scale production of titania nanoparticles (NPs). The synthesis involves a polycondensation reaction of alkoxide precursors during the heating at 70 °C. A W/O microemulsion with a volume ratio of 1:1 was obtained using cetylpyridinium bromide (CPB) as a cationic surfactant. Structural and functional characterization of the samples was conducted using X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The photoactivity of the nanostructured titania was evaluated by measuring the photodegradation of Methylene blue (MB). The results indicate that the photoactivity depends on the sinterization grade of the titania nanoparticles. Commercial titania nanoparticles (P25) were used as a reference material commonly employed for coating stone protection in the field of Cultural Heritage Conservation.

Francesca Boccaccini, Aurelio Barbetta, Elena Messina, Marianna Pascucci, Cristina Riccucci, Gabriella Di Carlo
Novel, effective and safe coatings for the protection of copper-based artefacts

Degradation processes in cultural heritage metal artefacts represents a critical issue since they can irreversibly compromise the conservation status of valuable works of art. The products used to hinder these processes are mainly based on harmful or toxic corrosion inhibitors and solvents. Namely, large amounts of organic solvents are typically used by conservators for the application and removal of protective materials. In the last decades, the search for new materials that can simultaneously satisfy protective, aesthetic and safety requirements is receiving an increasing attention.
In this contest, we have focused our attention on the development of sustainable polymer coatings that can provide an active protection and that are easy to be applied and removed using water-based solvents. A green polymer from renewable sources, such as chitosan, was selected and functionalized with anticorrosive species. Validation tests were performed on model copper-based substrates with different composition and surface finish. The performances were compared with a commercial benchmark.

Arianna Ceci, Luca Lanteri, Claudia Pelosi, Paola Pogliani, Sabrina Sottile
Analysis of materials of wax Christ-children from the Monastery of Santa Rosa in Viterbo

This paper reports the results of the analysis performed on three wax Christ-children (wax Bambinelli) preserved in the monastery of Santa Rosa in Viterbo. The analysis was performed on the occasion of the restoration, recently concluded, with the aim at supporting the working operations. The characterisation of the materials was particularly relevant for this kind of objects because they are little studied being considered of lesser artistic relevance than other artworks. But the wax babies are very important for their religious values and for technical details and peculiarities: apart from wax, precious textiles and decoration can be found in their dresses and ornaments. The materials were characterised by 2D and 3D ultraviolet fluorescence imaging, X-ray fluorescence spectroscopy, Fourier Transform Infrared spectroscopy, optical microscopy.
These techniques were used for investigating both the waxy mixture composition and the textile fibers of the babies hair

Angelja Kjara Surca, Mohor Mihelčič
Electrochemistry and vibrational spectroscopy in investigation of protective coatings for bronze artworks

Herein are discussed the possibilities of how to exploit vibrational spectroscopic and electrochemical techniques in the studies of protective coatings for bronze artworks. Protective coatings for bronze 85,555 are prepared on the basis of polyurethanes or fluoropolymers. Reflection-absorption infrared spectroscopy under near grazing conditions is described as a powerful tool for studying the surfaces of bronze when exposed to various conditions (solutions, strippers, temperature). Electrochemical techniques, especially the potentiodynamic polarization technique, are very powerful in the evaluation of protective coatings. A combination of electrochemical and spectroscopic techniques, however, enables to follow changes in the protective coating that occur with an increase in an anodic potential. This is an accelerated test and similar changes are expected to occur in the protective coatings with time, i.e., exposure to atmospheric conditions (rain, humidity …). Various solutions were also tested as strippers to evaluate the removability of coatings.

Penka Girginova, Cristina Galacho
Cellulose ethers and nanoconsolidants: preliminary observations on the suitability of the use of cellulose derivatives in the synthesis of nanolime particles

This communication reports the preliminary results of our ongoing research on the effect of addition of cellulose-derivatives, such as cellulose ethers, in the synthesis of calcium hydroxide (Ca(OH)2) micro-sized particles. Particles of Ca(OH)2 were synthesised without and with addition of different amounts hydroxypropyl methylcellulose (HPMC). The obtained particles were characterized with X-ray diffraction (XRD), scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR). Our preliminary results anticipate that syntheses with addition of HPMC originated the formation of smaller and more uniform in shape and size Ca(OH)2 particles in comparison with the Ca(OH)2 particles synthesized without addition of HPMC. This study contributes to the urgent need of innovative non-toxic sustainable materials, compatible with the original artworks, with long-term efficiency and easy for application.

Page 12 of 936 Results 111 - 120 of 9356