ABSTRACT: We present the azulejoteca, a physical archive of Portuguese azulejos specimens and test items, as well as a digital database with their characterization data, both accessible to the scientific community for research on this iconic cultural heritage of Portugal. In time, the digital database will be integrated into DIGILAB, the digital platform of the forming European Research Infrastructure for Heritage Science (E-RIHS).
1. INTRODUCTION
Architecturally integrated Portuguese faïence tiles (azulejos) are important, both to Portuguese culture and, for their uniqueness, to the art heritage of Mankind. Their continuous use in Portugal for over 500 years in a well dated succession of stylistic solutions and applications adapted to the needs of each time defined a national affinity which is, in itself, a rich field for social study (Santos 1957, Meco 1993).
There are however important gaps in the knowledge of the history of Portuguese azulejos, not least the elusive origin of the manufacture in the country and its technological sources, which need additional research (Simões 1990, Pais 2012). In the framework of the project FCT-AzuRe,1 we aim to contribute to bring clarification on those issues, not only through dedicated research, but also by giving others the opportunity to share characterization data specifically gathered, as well as data already extant but not generally available. With this idea in mind, and aware that sharing information could play a crucial role in the explanation of unclear aspects in the studies of this unique historical and cultural heritage, we set out to create a “library” of Portuguese
azulejos - the so-called azulejoteca, together with
online information on their morphological and analytical characteristics.
2. THE AZULEJOTECA
The azulejoteca concept results from a pioneering idea of creating a collection of azulejo tiles and
samples, to which all researchers will be able to resort to integrate in their studies or to gather supplemental data that will be add to that already extant. It consists of a physical archive of characterized azulejo specimens, from the 16th to the 20th century, representing 400 years of azulejo chronology, and will be located at the Museu Nacional do Azulejo (National Azulejo Museum) in Lisbon, Portugal.
For each azulejo different types of samples will be placed in the archive: fragments (when possible or available), polished sections used for instrumental characterization, including micro-samples for SEM- EDS analysis, and ground ceramic body samples (when available) for XRD analysis (see Fig. 1). Any samples kept in the archive are easily traceable to the
azulejos from which they were collected.
Figure 1. Example of the type of samples that can be found in the archive.
3. THE DIGITAL DATABASE ON AZULEJOS The characterization data of all azulejos specimens placed in the archive are available through a digital database, which researchers can easily access by the Internet. The data is organized in three main areas: i) morphological characterization data; ii) physical characterization data and iii) chemical and mineralogical characterization data.
Figure 2. Morphological characterization data that can be found in the digital database: macroscopic observations; OM images and SEM images (top to bottom).
4. MORPHOLOGICAL CHARACTERIZATION DATA
Under this heading is presented data related to macroscopic observations, such as the dimensions of the azulejo, surface colours or notes on the ceramic body features and manufacturing defects (Fig. 2), as well as information on other morphological characteristics obtained by optical microscopy (OM) and scanning electron microscopy (SEM). Both optical and electronic images are shown and may be retrieved in high resolution (Fig. 2).
5. PHYSICAL CHARACTERIZATION DATA Whenever available, the physical properties of the azulejos, particularly their porosity and hydric behaviour, are presented (Fig. 3).
Figure 3. Example of the porosity and hydric behavior data that can be found in the digital database.
6. CHEMICAL AND MINERALOGICAL CHARACTERIZATION DATA
Characterization data concerning the chemical composition of the glaze, ceramic body and pigments is provided. Here, one can find data obtained by SEM- EDS analysis (scanning electron microscope coupled to an energy-dispersive spectrometer), X-ray fluorescence analysis (ED-XRF) and thermogravi- metric and differential thermal analysis (TGA-DTA) (Fig. 4). In the case of the SEM-EDS and XRF analyses, it is also possible to accede the raw data.
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Figure 4. Example of the chemical characterization data that can be found in the digital database: SEM-EDS data; XRF spectrum and TGA-DTA data (left to right and top to bottom).
Whenever available, data related to the mineralogical composition of the ceramic body, obtained by X-ray diffractometry (XRD) is also presented (Fig. 5).
Figure 5. Example of the mineralogical characterization data that can be found in the digital database.
7. THE DIGILAB PLATFORM
Portugal, through LNEC and the HERCULES Laboratory of the University of Évora, are involved in the organization of the European Research Infrastructure for Heritage Science (E-RIHS)1 which entered the European strategic roadmap for research infrastructures in 2016 and is expected to be fully functional by 2022. E-RIHS will provide state-of-the- art tools and services to cross-disciplinary research communities through several platforms, one of which - DIGILAB for virtual access to tools and data hubs for heritage research including measurement results, analytical data and documentation (Striova 2017). The digital database on azulejos is set to integrate DIGILAB at its first stage.
8. CONCLUSIONS
The “azulejoteca” (a library of azulejos) that will consist of a collection of azulejos and samples, together with the respective analytical results, it’s an
innovative concept, henceforward open to all researchers. These will also be made available to the scientific community through an Internet database, to help researchers on their studies and to support the expansion of knowledge about this relevant artistic heritage.
9. REFERENCES
Meco, José 1993. O azulejo em Portugal. Lisboa: Publicações Alfa.
Pais, A. N. 2012. “Fabricado no Reino Lusitano, O que antes
nos vendeu tão caro a China”: a produção de faiança em Lisboa, entre os reinados de Filipe II e D. João V. Porto:
Escola das Artes da Universidade Católica Portuguesa (Tese de doutoramento).
Santos, Reynaldo dos 1957. O azulejo em Portugal. Lisboa: Editorial Sul.
Simões, J.M. dos Santos 1990. Azulejaria em Portugal nos
séculos XV e XVI. 2ª ed. Lisboa: Fundação Calouste
Gulbenkian.
Striova, Jana & Pezzati, Luca 2017. The European Research
Infrastructure for Heritage Science (E-RIHS), The Int.
Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences, Vol.XLII-2/W5, pps. 661-664. 26th Int. CIPA Symp. - Ottawa, Canada.
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