Sara Fiorentino

The connection between Umayyad and Byzantine mosaic manufacture is a debated issue: on the one hand, Arab sources report that Umayyad caliphs received craftspeople and materials to adorn religious buildings from the Byzantine emperor; on the other hand, the reliability of these texts has long been disputed among scholars, and other possible influences have been hypothesised. Was early Islamic mosaic manufacture related to Byzantine tradition and to what extent? Were materials and artisans gathered from Byzantium and/or territories under the Byzantine control? Based on a multi-analytical approach, glass tesserae from Khirbat al-Mafjar, the Great Mosque of Damascus, and the Dome of the Rock have been analysed. Results speak of a tale of two legacies, demonstrating that, parallel to a continuity with the manufacture of glass tesserae in the late antique Levant—pointing, more specifically, to a re-use of materials from abandoned buildings—legacies other than Byzantine occurred. It emerged that Egypt definitively played a role in mosaic making during the Umayyad caliphate, acting as a supplier of skilled artisans and materials.

This study aimed at laying the groundwork for a compendium on mineralogical phases responsible for the colors and opacity of ancient glasses, with specific reference to mosaic tesserae. Based on the awareness that a comprehensive database of these phases is currently lacking in the available literature, this compendium foresees two main objectives. The first scope was to set the basis for a well-structured database, as a reference point for scholars from different backgrounds for comparative and methodological purposes. The second goal was to provide insights on analytical methods that could be profitably used for achieving an in-depth characterization of coloring and opacifying inclusions; a tailored multi-analytical approach based on easily accessible and widespread techniques like OM, SEM-EDS, μ-Raman, and XRPD is proposed here. Micro-structural and compositional features of glass tesserae, where different types of crystalline phases were detected (Sb-based, Sn-based, Cu-based, Ca-phosphate-based) are presented in well-structured synoptic tables, following a summary on historical-archaeological information on their use.

The paper discusses the case study of the Marriage at Cana, a sixteenth century wall painting located in Ravenna and executed by Luca Longhi. A multi-analytical approach based upon OM, SEM-EDS, μ-Raman, μ-FTIR and biological analyses was selected to investigate the painting technique and the state of preservation of the artwork, compromised by a severe alteration. Data demonstrated that the artwork was executed with a dry painting technique: a siccative oil was used as binder, while indigo, lead white, carbon black, ochres, vermilion and red lead were identified as pigments. Biological analyses clearly allowed identifying Eurotium halophilicum as the fungus responsible for the white patina compromising the painted surface and, according to this result, Biotin T was selected as the most effective biocide to stop the biological attack. The precarious conditions in which the painting was, attributable to previously performed interventions and to the conservation environment, laid the groundwork for a challenging restoration conducted in 2016. Scientific analyses better clarified the kind of materials employed in the execution on the artwork, as well as how the previous restoration was carried out; furthermore, analytical data methodologically supported phases of the intervention like cleaning, filling of the lacunae and pictorial retouching, as products were selected on the basis of their affinity to original materials and painting technique. This study will hopefully encourage reflections on how a synergic dialogue between conservation science and restoration can represent an important reference point for interventions to be conducted with scientific criteria and suitable methodology, in the light of the shared vision and common goal of transferring patrimony to future generations.

This paper deals with a Thermoluminescence (TL) study of ancient mosaic tesserae from the qasr (winter residence) of Khirbat al-Mafjar, amazing palace of the Islamic caliphs located in the plain of Jericho. In literature, works dealing with the dating of mosaic tesserae usually rely on the dosimetric properties of the microcrystalline inclusions in the silica matrix rather than on the matrix itself. On the other hand, in the last decades, commercial glasses have been demonstrated to be suitable for retrospective accidental dosimetry. In this work, we applied a protocol widely used for the mobile phones’ glasses, the so-called “pre-bleached with blue LEDs” protocol, to evaluate the archeological dose absorbed by some Khirbat al-Mafjar tesserae in order to confirm their dating based on archaeological evidence. As for commercial glasses, the TL signal from ancient tesserae presents anomalous fading and it is light sensitive. The experimental protocol circumvents these problems isolating the thermally more stable TL signal with an optical pretreatment and allowing the determination of a fading curve for each analyzed sample. Using an integrative approach, we estimated the fading correction for these tesserae and we retrieved their ages. The results are partially in agreement with those hypothesized on historical ground and show good potentialities for the dating of amorphous archaeological glassy materials.

The results of scientific analyses performed on the travertine parts of the National Monument to Francesco Baracca in Lugo di Romagna (Ravenna, Italy) are reported and discussed. The aim of the research is an in-depth knowledge of the constituent material in view of technological and conservation aspects, to support the first significant restoration work (held in 2014) concerning the Monument created by the artist Domenico Rambelli in 1936, a masterpiece of monumental Italian twentieth century architecture. RLM, SEM/EDS, XRD and micro-FTIR analyses were carried out on micro-samples to characterize the different original surface finishing and the degradation phenomena. VIS-RS, RLM and SEM/EDS investigations were also performed to evaluate the application of a nanoparticle titanium dioxide—based coating on the stone surfaces.

A multi-analytical approach was carried out to investigate building materials and degradation patterns affecting the so-called "Droctulf Wall", located in Piazzetta degli Ariani, Ravenna.
The case study falls within a multi-disciplinary project, ArianInPiazza (http://patrimonioculturale.unibo.it/arianinpiazza/), developed by the University of Bologna - Department of Cultural Heritage and aimed at proposing an intergrated approach for the conservation and promotion of Cultural Heritage.

Oral presentation | X Congresso dell’Associazione Italiana di Archeometria (AiAr 2018), Turin, Italy, 14-17 February 2018

The opportunity of improving public engagement through conservation science is among the most discussed topics in the international scientific community, as it is of primary and crucial importance for the future of this field of research [Lithgow 2015].
Between 2014 and 2017, the collaboration on a research project focused upon Palazzo Guiccioli (Ravenna, Italy) made us aware of the necessity to stretch our “comfort zone” beyond the traditional media that convey scientific information, as well as to develop innovative ways in which disciplines contributing to the knowledge and conservation of our heritage can be effectively communicated to a broaden non-specialist audience to endorse public engagement.
Owing its fame to the poet Lord Byron, who used to reside there during his stays in Ravenna, Palazzo Guiccioli was named after the count Alessandro Guiccioli, who bought the building in 1802 by the Osio family. In 2015, a massive conservation project of the whole building was started: under coatings of modern varnishes, overlapping layers of paintings were discovered on walls and vaults, witnesses of different occupation phases of the building. By a multi-analytical approach (OM, SEM-EDS, micro-FTIR, micro-Raman, XRPD), a characterisation of both degradation patterns and painting techniques was carried out: apart from sustaining the conservation work, obtained data also supported the historical study of the decorative programme, leading to the emergence of relevant insights into the possible attribution to specific workshops [Melis 2017].
In 2018, Palazzo Guiccioli will be opened again, intended for hosting the Risorgimento and Lord Byron Museum. To prevent obtained results from only being shared within experts, we have developed CONCEPTS (CONservation scienCE for Public engagemenT increaSe), a model built in accordance with the available recommendations concerning effective communication for cultural heritage [Lithgow 2015, Ingram 2011, UNESCO 2007, Tilden 1957]. Based on an intuitive questions and answers interface, CONCEPTS is an easily approachable virtual space intended to avoid sterile information and guide people to interpretation through evidence, by using interactive layered data to provoke and stretch the public. CONCEPTS will let the palace, its building materials and decorative programme speak for themselves, by “answering” questions made by the visitors. In this presentation, authors will show how results obtained by merging historical research and scientific analyses will dialogue together and with the public by using CONCEPTS, with the main aim to make people aware of how heritage can enormously benefit from an interdisciplinary research and to propose a model where engagement is made with the public.

Oral presentation | XXI Congress of the International Association for the History of Glass (AIHV21), Istanbul, Turkey, 3-10 September 2018

In the panorama of ancient glass manufacture, several aspects concerning the glass industry under the Umayyad caliphate still need to be investigated.
While our knowledge of Umayyad glassware has been enhanced by recent research thanks to combined typological and archaeometric studies, when considering mosaic glass tesserae even a preliminary scenario is lacking.
A pivotal issue to be addressed is the relationship between Umayyad and Byzantine mosaic manufacture and technology. Muslim literary sources claim that Umayyad caliphs got from the Byzantine emperor workmen and materials to construct and decorate religious buildings, like the Prophet’s Mosque at Medina and the Great Mosque of Damascus. Nevertheless, the issue of the sent tesserae has arisen several problems due to the reliability of the sources themselves. Furthermore, the Aphrodito papyri (a document from Upper Egypt, reporting a correspondence between the Governor of Egypt and the Prefect of the District of Aphrodito) also refers to materials and skilled craftsmen being sent from Egypt to Jerusalem and Damascus, to collaborate on the construction of the al-Aqsa mosque and the Great Mosque.
In this paper, authors will present data achieved by analyses performed on two assemblages of Umayyad glass tesserae from the qasr of Khirbet al-Mafjar and the Great Mosque of Damascus. A multi-analytical approach allowed achieving remarkable outcomes on both the base glass (EPMA, LA-ICP-MS) and the colourants and opacifiers (SEM-EDS, m-Raman, XRPD). Achieved data provide an intriguing picture, with the first scientific evidence of a non-exclusive gathering of materials from the Byzantines in the manufacture of Umayyad mosaics. Framing the data in the broaden scenario of mosaic glass tesserae consumption in the eastern Mediterranean basin, preliminary hypotheses on models for the manufacture and trade of mosaic glass tesserae under the Umayyad will also be discussed, shedding a new light on these mosaics of cultures.

Oral presentation by invitation held at the Workshop: Conservation of outdoor works of art. Study of the influence of UV radiation and atmospheric particulate in the degradation mechanism (Department of Cultural Heritage, Alma Mater Studiorum - University of Bologna)

Cultural heritage goes beyond material features of objects and works of art. It witnesses ideas, cultural relations, symbolic and social values, technological solutions. Such a heterogeneity of meanings requires a strong opening towards trans-disciplinary approaches, since applied research to cultural heritage cannot ignore a jointed methodology based on both humanistic and scientific fields.
From this awareness, the project Heaven is a Place on Earth was born: a research project in the field of glass studies, with special emphasis on stained glass. Using a blend of interdisciplinary expertise, we analyse both the materiality of glass and Christian intellectual development, pursuing human-centred research interests. Our main aim is to further current knowledge of the significance of stained glass in time, space, and above all the history of the imaginary. The research will thus focus on both the materiality of glass – the choice of raw materials, stained glass manufacturing technology, and the production of specific hues – and its immaterial nature, exploring aspects such as forms of light and choreographed interplay of colours.

The talk, delivered under invitation at AI-NURECC PLUS Conference “CREATIVE AND CULTURAL INDUSTRIES IN THE ADRIATIC-IONIAN REGION”, focused on the potential contribution that material culture can provide to the enhancement of Cultural and Creative Industries. Material culture is a physical and tangible witness of our story: it encompasses physical objects, resources, and spaces that people used to define their culture in the past. Today, material culture finds its expression in craftsmanship, in local and traditional manufactures passing down, from generation to generation, knowledge and know-how. Physical features of these objects hidden intangible values made of knowledge, know-how and socio-cultural relations. Cultural and creative industries are, therefore, the ideal places where this knowledge can find fertile ground and continue to live, with all the intangible meanings of which they are custodians.

The poster, presented on the occasion of the XX National Glass Study Days (AIHV - International Association for the History of Glass - Italian National Committee), aims to be a starting point for reflection on the comparability of archaeometric data and on the need to define a shared diagnostic approach.