The classification and conservation of ancient artworks (belonging to collections) is of important cultural, historical, and economic concern. However, ancient textiles often display structural damage that renders them fragile and unsuitable for exhibition. One of the most common types of damage is linked to erroneous restoration treatments, among which the application of glues to consolidate cuts. Harsh strategies, such as mechanical or chemical treatments, are not suitable since they can cause further impairment of the fabric, whereas mild approaches, like wet cleaning, are often ineffective, as also demonstrated by the present study. Here, we have explored the possibility of using gellan-immobilized enzymes of bacterial origin (Bacillus alpha-amylase) to obtain a satisfactory starch removal from a damaged archaeological tunic-shroud from the Turin Egyptian Museum (Italy), without altering the original yarns or textile fibers. This method, already applied to clean casein-damaged wall paintings, as well as cotton, silk, and linen fabrics, has proved to be optimal for the treatment of a wool burial shroud and to be able to definitively solve fragile textile restoration problems. Moreover, efforts have been made to obtain insights into the artwork: a multidisciplinary approach has allowed to obtain a correct chronological attribution (radiocarbon dating) and fabric fiber characterization (SEM-EDX) as well as shed light on the colored parts and dark stains (FORS+IRFC and XRF). Finally, the evaluation of the type of glue, by Fourier transform infrared spectroscopy, has suggested the best enzyme for glue removal. These results have demonstrated that a mild bio-based approach is a successful tool for the treatment of archaeological textiles in critical conditions.

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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 (CCR) 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, 4 binders, 2 varnishes and 4 different materials for underdrawings. In collaboration with the Laboratorio Analisi Scientifiche (LAS) of Regione Autonoma Valle d'Aosta, the National Institute of Metrological Research (INRIM) and the Department of Architecture and Design (LAMSA) of the Polytechnic of Turin, we created a scientific database that is now available online (http://www.centrorestaurovenaria.it/en/areas/diagnostic/pictorialmaterials-database) designed as a tool for heritage science and conservation. Here we present a focus on materials for pictorial retouching where the hyperspectral imaging (HSI) 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 (FORS) 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.1 Mowilith DM5: PVAc and acrylic ester in aqueous solution, plasticizer free, Sinopia SAS datasheet [21]. 2 Linseed oil was also used as binder for gamboge, madder and indigo, as reported in literature.

Diagnostic physical methods are increasingly applied to Cultural Heritage both for scientific investigations and conservation purposes. In particular, the X-ray imaging techniques of computed tomography (CT) and digital radiography (DR) are non-destructive investigation methods to study an object, being able to give information on its inner structure. In this paper, we present the results of the X-ray imaging study on an ancient Egyptian statuette (Late Period 722–30 BCE) belonging to the collection of Museo Egizio in Torino and representing an Egyptian goddess called Taweret, carved on wood and gilded with some colored details. Since few specific studies have been focused on materials and techniques used in Ancient Egypt for gilding, a detailed investigation was started in order to verify the technical features of the decoration in this sculpture. Specifically, DR and CT analyses have been performed at the Centro Conservazione e Restauro “La Venaria Reale” (CCR), with a new high resolution flat-panel detector, that allowed us to perform tomographic analysis reaching a final resolution better than the one achievable with the previous apparatus operating in the CCR.

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The multidisciplinary and multi‐technical study of the coffin lid of Neskhonsuennekhy (Turin, Museo Egizio, inventory number S.05245) datable to the 26th dynasty (664–525 BC) was launched in 2015 at the Centro Conservazione e Restauro La Venaria Reale during the conservation activities required by the Museo Egizio, as part of wider research on the so‐called red coffins. Widespread abrasions and gaps in the pictorial stratigraphy strongly impeded the reading of the decoration, and a reddish and locally blackened material was covering many areas. Integrating multispectral imaging (UV fluorescence, VIL, IR reflectography), MA‐XRF, radiography, and analyses on micro‐samplings (OM, SEM‐EDX, FT‐IR) allowed deepening the state of preservation, detecting previous intervention, and characterizing the blackened surface, necessary to define the cleaning intervention objectives. In particular, the IR reflectography allowed recovering the readability of the beautiful drawings and the ancient hieroglyphs hidden beneath the reddish blackened surface. Based on the analytical data and compatibility with the pigments known in ancient Egypt, it was possible to return to the public the original lost decoration with a descriptive and virtual reconstruction. The new LANDIS‐X scanning station equipped with a real‐time macro XRF was fundamental for studying pigments, glazes, and mixtures besides the presence of lead impurities in the copper source used to make the Egyptian blue pigment, encouraging the research on the sources of mineral supply. Finally, this study allowed understanding the technique of execution of the find, from the assembly of the wooden elements to the reddish finish, noticing analogies with the other red coffins.

Hyperspectral imaging is a technique of analysis that associates to each pixel of the image the spectral content of the radiation coming from the scene. This content can be helpful to recognize the chemical nature of the materials within the scene or to calculate their colours under particular conditions. Different solutions of hyperspectral imager have been realized with different spatial resolution, spectral resolution and range in the electromagnetic spectrum. In particular, improving the spectral resolution allows discriminating smaller features in the spectrum and the unambiguous detection of the absorption bands characteristic of superficial materials. Hyperspectral imagers based on interferometers have the advantage of having a spectral resolution that can be varied according to the needs by changing the optical path delay of the interferometer. A spectrum for each pixel is obtained with an algorithm based on the Fourier transform of the calibrated interferogram. We present the results of the application of a hyperspectral imager based on Fabry‐Perot interferometers to the field of cultural heritage. On different artworks, the hyperspectral imager has been used for pigment recognition, for colour rendering elaborations of the image with different light sources or standard illuminants and for calculating the chromatic coordinates useful for specific purposes