Search

Digitalization techniques, such as photogrammetry (PG), are attracting the interest of experts in the cultural heritage field, as they enable the creation of three-dimensional virtual replicas of historical artifacts with 2D digital images. Indeed, PG allows for acquiring data regarding the overall appearance of an artifact, its geometry, and its texture. Furthermore, among several image-based techniques exploited for the conservation of works of art, multispectral imaging (MSI) finds great application in the study of the materials of historical items, taking advantage of the different responses of materials when exposed to specific wavelengths. Despite their great usefulness, PG and MSI are often used as separate tools. Integrating radiometric and geometrical data can notably expand the information carried by a 3D model. Therefore, this paper presents a novel research methodology that enables the acquisition of multispectral 3D models, combining the outcomes of PG and MSI (Visible (VIS), Ultraviolet-induced Visible Luminescence (UVL), Ultraviolet-Reflected (UVR), and Ultraviolet-Reflected False Color (UVR-FC) imaging) in a single coordinate system, using an affordable tunable set-up and open-source software. The approach has been employed for the study of two wooden artifacts from the Museo Egizio di Torino to investigate the materials present on the surface and provide information that could support the design of suitable conservation treatments.

The conservation of artworks requires a profound knowledge about pictorial materials, their chemical and physical properties and their interaction and/or degradation processes. For this reason, pictorial materials databases are widely used to study and investigate cultural heritage. At Centre for Conservation and Restoration La Venaria Reale, we prepared a set of about 1200 mock-ups with 173 different pigments and/or dyes, used across all the historical times or as products for conservation, four binders, two varnishes and four different materials for underdrawings. In collaboration with the Laboratorio Analisi Scientifiche of Regione Autonoma Valle d’Aosta, the National Institute of Metrological Research and the Department of Architecture and Design of the Polytechnic of Turin, we created a scientific database that is now available online ( http://www.centrorestaurovenaria.it/en/areas/diagnostic/pictorial-materials-database ) designed as a tool for heritage science and conservation. Here, we present a focus on materials for pictorial retouching where the hyperspectral imaging application, conducted with a prototype of new technology, allowed to provide a list of pigments that could be more suitable for conservation treatments and pictorial retouching. Then we present the case study of the industrial painting Notte Barbara (1962) by Pinot Gallizio where the use of the database including modern and contemporary art materials showed to be very useful and where the fibre optics reflectance spectroscopy technique was decisive for pigment identification purpose. Later in this research, the mock-ups will be exploited to study degradation processes, e.g., the lightfastness, or the possible formation of interaction products, e.g., metal carboxylates.

Yves Klein's Sculptures-Eponge are natural sea sponges soaked in International Klein Blue (IKB), assembled on metal pedestals. This work examines the constituent materials, the execution technique and the deterioration problems of the sculptures which are covered by a friable matt paint, in order to define the guidelines for treatment and collections care. For the experimental work, samples were prepared in the laboratory with the same materials and techniques used by the artist. In order to solve problems relating to removal of dust deposits, many aspects were considered in the evaluation process, such as the presence of an organic and porous support, not discussion in the existing literature, the poor cohesion of the surface and Klein's specific recommendations for handling his Monochromes only with gloves, and removing dust while avoiding any contact with the painted layers. Photo-ablation using laser radiation was identified as a possible solution. Three Nd:YAG lasers with different pulse dura...

In this paper we will report on the importance of 3D documentation as a tool for study and communication in Cultural Heritage, with particular reference to the experience grown up at Centro Conservazione e Restauro La Venaria Reale (in the text: CCR La Venaria Reale) and to its application on Egyptian artefacts. We will focus on the purpose-built virtual viewer, set up in order to solve specific operational needs of the working group. We will consider for that significant case studies for innovation that 3D technology has brought in terms of streamlining processes and sharing results. We will also focus on technical advantages obtained by the realization of a 3D model of the remains of a 22nd dynasty cartonnage, found by the Italian Archaeological Mission at the area of the Temple of Millions of Years of Amenhotep II (Luxor, West bank, Egypt), and on the benefit in using 3D documentation on archaeological excavations.

This contribution focuses on the conservation of an Egyptian wooden sculpture (Inventory Number Cat. 745) belonging to the Museo Egizio of Torino in northwest Italy. A preliminary and interdisciplinary study of constituent painting materials and their layering is here provided. It was conducted by means of a multi-technique approach starting from non-invasive multispectral analysis on the whole object, and subsequently, on selected micro-samples. In particular, visible fluorescence induced by ultraviolet radiation (UVF), infrared reflectography (IRR) and visible--induced infrared luminescence were used on the whole object. The micro-samples were analysed by means of an optical microscope with visible and UV light sources, a scanning electron microscope (SEM) with an energy-dispersive X-ray spectrometer (EDX), Fourier transform infrared (FT-IR) spectrometer, pyrolysis-gas chromatography/mass spectrometer (Py-GC/MS) and micro-particle induced X-ray emission (PIXE). The characterization of the painting materials allowed the detection of Egyptian blue and Egyptian green, and also confirmed the pertinence of the top brown layer to the original materials, which is a key point to design a suitable surface treatment. In fact, due to the water sensitiveness of the original materials, only few options were available to perform cleaning operations on this artwork. To setup the cleaning procedure, we performed several preliminary tests on mockups using dry cleaning materials, commonly used to treat reactive surfaces, and innovative highly water retentive hydrogels, which can potentially limit the mechanical action on the original surface while proving excellent cleaning results. Overall, this study has proved fundamental to increase our knowledge on ancient Egyptian artistic techniques and contribute to hypothesize the possible provenance of the artefact. It also demonstrated that polyvinyl alcohol-based retentive gels allow for the safe and efficient cleaning of extremely water sensitive painted surfaces, as those typical of ancient Egyptian artefacts.