The treatment of ancient Portuguese tiles

Abstract

The preservation of the vast cultural heritage of tiles in Portugal requires the development of a systematic scientific and technological approach. In this communication the case of the treatment of a panel of ancient tIles is described. The main problem was the cleaning and consolidation of the piece, followed by restoration for exhibition. The treatment was preceded by a study of the materials, consisting of analyses of the ceramic body and the glazed surface. The removal of aged waxes and resins was achieved using appropriate solvents and the consolidation of the ceramic body was carried out by an inorganic treatment. For the reconstruction of missing parts and the mounting of the panel materials were chosen which would avoid interaction with the original material.     

Diagnosis of pathologies in ancient (seventeenth-eighteenth centuries) decorative blue-and-white ceramic tiles: Green stains in the glazes of a panel depicting Lisbon prior to the 1755 earthquake

Decorative panels of ceramic glazed tiles comprise a valuable cultural heritage in Mediterranean countries. Their preservation requires the development of a systematic scientific approach. Exposure to an open-air environment allows for a large span of deterioration effects. Successfully overcoming these effects demands a careful identification of involved degradation processes. Among these, the development of micro-organisms and concomitant glaze surface staining is a very common effect observed in panels manufactured centuries ago. This paper describes a study on the nature of green stains appearing at the surface of blue-and-white tile glazes from a large decorative panel with more than one thousand tiles, called Vista de Lisboa that depicts the city before the destruction caused by the 1755 earthquake. The characterization of green-stained blue-and-white tile glazes was performed using non-destructive X-ray techniques (diffraction and fluorescence spectrometry) by directly irradiating the surface of small tile fragments, complemented by a destructive scanning electron microscopy (SEM) observation of one fragment. Despite the green staining, analytical X-ray data showed that no deterioration had occurred irrespective of the blue or white color, while complementary SEM-EDX data provided chemical evidence of microorganism colonization at the stained glaze surface.     

The structural study of Ghaffarieh Dome tile-workings in Maragheh Town based on laboratory studies

The history of using tiles in Persian architecture dates back to the eleventh century. In the beginning, tiles were made of bricks and mounted with plaster. Thereafter, however, tiles were replaced with mosaics to decorate buildings. The technique of applying mosaics began in the thirteenth century and reached its summit during the Ilkhanid and Timurid periods between the fourteenth to sixteenth centuries. One of the most outstanding buildings in which mosaics were widely used is Ghaffarieh Dome, a fourteenth-century building in Maragheh, Eastern Azerbaijan. The Dome is especially noteworthy for its unique mosaic workings. Therefore, a thorough examination of the mosaics used in the Dome may pave the way for closer studies of the Ilkhanid mosaics (tile-workings) in Iran. Since there is little information on the material aspects of mosaics used in the Ghaffarieh Dome, the body and glaze of the mosaics were examined through instrumental analyses. In order to interpret the results of the analyses, they were compared with existing data about similar mosaics of Islamic lands. The presence of pyroxene (aluminum diopside) in some of the mosaic bodies revealed that the firing temperature limit in the kiln was not, most likely, uniform. Two kinds of glazes, alkaline and lead-based, were used to produce black and turquoise colors.     

Study of the deterioration products,gilding, and polychromy of the stones of the Scuola Grande Di San Marco's façade in Venice

The Scuola Grande di San Marco is one of the most outstanding Renaissance buildings in Venice. Destroyed by fire in 1485, the Scuola was reconstructed between 1487 and 1495 by Pietro Lombardi (and sons), together with Giovanni Buora and Mauro Codussi. The façade is considered one of the finest and most original exteriors of Venetian buildings and in particular features refined sculptural and painted decorations and a remarkable pictorial effect created by the extensive use of polychrome marbles and the false perspective view between the pilasters of the lower order. Most of the stone materials (Istrian and Verona red limestones, nero di Roveré, pavonazzetto toscano, Carrara marble and various reused antique marbles) present evident decay phenomena such as scaling, exfoliation, powdering, fissuring, salt efflorescence, black crusts, and artificial patinas of various kinds. The present study reports the results of petrographic and chemical laboratory analyses carried out in preparation for the conservation treatment of the building, in order to characterize the main micro- and macro-morphologies of decay and to identify the causes and mechanisms of deterioration as well as the nature and application technique of the polychromy, gilding, and patinas present on parts of the monumental Renaissance façade.     

Analysis and conservation of three Hispano-Moresque textiles dating from the first half of the twelfth century

Abstract

Three Hispano-Moresque woven textiles dating from the first half of the twelfth century were restored for an exhibition. The first two are from the reliquary of St Librada in Sigüenza cathedral and the third is from the tomb of St Bernard Calvó in Vich. The first piece depicts addorsed griffins, the second, eagles with extended wings and the third, facing sphinxes. Contained within circles, they belong to a class of textile known in mediaeval documents as pallia-rotata. The spaces between the circles are decorated with typically Islamic designs, and with representations of plants and animals. A similar material was used for all three pieces: silk for both warp and weft, with gold thread for certain decorative motifs. All three textiles were found in a fragmentary condition; they had been glued and sewn onto thin card. The fibres were in a fairly weak state and had lost much oftheir flexibility and resistance. Apart from the work of restoration, the dyestuffs and the metal thread were analyzed and the decorative motifs were reconstructed using scale drawings.     

Mineralogical,Chemical, and Thermal Characterizations of Historic Lime Plasters of Thirteenth–Sixteenth-century Daulatabad Fort,India

Iron ore as pozzolanic filler is an uncommon constituent of historic plaster rarely reported in any research. This paper presents one such study from western India where hematite instead of crushed bricks was identified as admixture in thirteenth–sixteenth-century CE Mughal masonry lime works of Daulatabad Fort. The outer/inner coat plasters from different locations of the fort were examined for morphological, mineralogical, chemical, and basic physical properties. The analytical investigative study was performed by optical microscopy, sieve analysis, X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectroscopy, Raman spectroscopy, SEM-EDX, and thermal analyzer. Although the plaster is dominantly made of micritic calcite and aggregate, incorporation of gypsum in the outer and inner coats has been detected and probably acted as a second binder. Cannabis sativa was mixed in the plaster, pointing to the knowledge of hempcrete technology by the makers of Daulatabad Fort. This investigation has now provided essential information with enough precision about this historic plaster for formulation of compatible repair materials essential for the site restoration.     

Examination and treatment of a seventeenth-century Spanish polychrome sculpture by Jose Caro

Abstract

The sculpture of St Gines de la Jara in the collection of the J. Paul Getty Museum, dated 1692, is an outstanding example of the estofado technique of imitating brocade in gold leaf and paint. The life-size figure retains most of its original polychromy. In previous restoration treatments, there had been an unsuccessful attempt to simulate the estofado. The present treatment included a comprehensive technical examination, using X-radiography to identify construction techniques and cross-sectional analysis for the layer structure and materials. The decoration of the sculpture was carefully studied with the goal of understanding more clearly the technique of the estofador. A cleaning strategy was then devised. Where there were losses in the estofado, it was decided to aim for a chromatic compensation using watercolours, rather than attempting to duplicate the original process.     

Enamel insert restorations on Limoges painted enamels: A study on a remarkable nineteenth-century restoration technique with particular attention to the original paillon designs

Two sixteenth-century Limoges painted enamel plaques by Léonard Limosin in the collection of the J. Paul Getty Museum, Los Angeles, show a remarkable restoration technique consisting of separately enameled pieces that have been inserted into areas where original enamel was lost. A detailed investigation of the two plaques brought information about this former restoration method and the materials used. Investigation included optical microscopy, UV-A examination, and X-radiography for identification and mapping of the insert restorations, scanning electron microscopy with energy dispersive X-ray spectroscopy, Fourier transform infrared spectroscopy, and gas chromatography-mass spectroscopy for analyzing organic restoration material as well as X-ray fluorescence for studying the enamel compositions. A survey of six other Limoges painted enamel collections in the USA was carried out, which revealed many more of these insert restorations and indicated particular damages related to the so-called paillon designs on silver or gold foils. A literature review was undertaken focusing on possible causes of the damage as well as on persons and workshops that may have executed the insert restorations.     

Monitoring and Mitigating Particulate Matter Deposition on Decorative Surfaces: Current and Future Approaches in the Palace of Westminster

ABSTRACT

Research into dust deposition rates on the wall paintings in the State Apartments at the Palace of Westminster, London, UK, began during the restoration of the encaustic floor tiles. The study has broadened to inform day-to-day preventive care for the extensive fine art collections on display and the intricately decorated Gothic interiors, providing a powerful tool for the forthcoming restoration and renewal of the Palace. Different monitoring methods, using optical microscopy, macro-photography and software-based image analysis, were investigated. Qualitative analysis with SEM-EDX and optical microscopy allowed the identification of a number of anthropogenic, geogenic and biological sources of particulate matter, while quantitative results elucidated deposition trends, highlighting both seasonal and works-related impacts. Results indicated that mitigation measures taken to protect works of art and limit the diffusion and deposition of particulate matter on surrounding surfaces were successful. A new dust monitoring method, based on imaging of vertical surfaces and on a recently developed image analysis workflow (CHIJ) operated in open-source software (ImageJ) was trialled alongside more traditional methods for measuring dust deposition through collection of particulate matter on proxies. Results showed significant discrepancies between data acquired directly on wall painting surfaces as compared to horizontal glass slides. The advantages, limitations and complementarity of both monitoring methods were identified, and their potential contributions to the development of data-driven conservation approaches for heritage sites were assessed. The relatively low-tech methods and equipment used present useful and adapted tools for collection managers and conservators to inform their decision-making processes.     

茶洋窑黑釉瓷器的科技分析研究

茶洋窑是福建南平市一处烧制多种釉色瓷器的宋元时期窑场。近年来窑址中发现的多种外销瓷产品,使其外销属性得到充分认识。本研究从科技考古角度对该窑场黑釉产品烧制技术进行考察,结果显示窑址周边有丰富、多样的制瓷粘土资源,采集的5份粘土可依据硅、铝、铁及钾等元素含量分为三类。胎体分析显示黑釉瓷制作时更偏向于选择富含铁元素的粘土,Si O2和Al2O3含量波动范围大。釉层制作时出于提升助溶剂和呈色目的,窑工有意选择一定量的草木灰及高铁粘土原料。窑址中相对高比例的生烧产品是由窑炉温度、制瓷原料特性(低助溶剂含量、高Al2O3)等多重因素所导致的。     

Confocal XRF depth profiling non-destructively reveals the original blue pigments in a Renaissance painting by Caroto

Recent restoration of The Rest on the Flight into Egypt by Giovanni Francesco Caroto, from the Louvre collections, included a technical examination of the Virgin's blue robe that aimed to characterize the original materials and later additions. The painting was examined using light microscopy and ultraviolet and infrared imaging, and one cross section was taken. None of these methods showed a clear distinction between the layers that were artist applied or modifications made by another hand. To gain information about the paint stratigraphy without taking additional samples, non-invasive confocal X-ray fluorescence (CXRF) analysis was carried out to examine several areas of the Virgin's robe. Using this technique, it was possible to identify the pigments and order of application of paint by the artist. All the pigments identified were considered to be artist applied, and on this basis no further cleaning was carried out and conservation proceeded with retouching of minor areas of loss or damage. This study highlights the advantages of CXRF analysis for the technical study of paintings, used in combination with classical methods for making informed conservation treatment decisions.     

How Popular Music is Exhibited by Museums in Portugal at the Beginning of the Twenty‐First Century: A Case Study

Popular music is deeply embedded in the dynamics of the contemporary world by means of its capacity to engender modes of privacy and publicness, to communicate emotion, and to enable us to create connections—and so to work within communities. Museums have traditionally addressed art‐music through the exhibition of musical instruments. But now that the exhibition of popular music has presented new challenges and opportunities worldwide for museum professionals, examining popular music discourses in museums is of the utmost importance in order for it to be meaningfully celebrated as instances of heritage. This paper expands on the representation of Popular Music in museums in Portugal at the beginning of the twenty‐first century by discussing a case study: the exhibition No Tempo do Gira‐Discos: Um Percurso Pela Produção Fonográfica Portuguesa at Museu Nacional da Música, Lisbon, Portugal, in 2007. Two methods of analysis are deployed: interviews with the curators, which revealed insights on their understanding of popular music, and analysis of the exhibition through discourse analysis, specifically through the lens of the analytical concepts genre and register. Although the curators had themselves previously developed insightful and innovative concepts with regard to popular music, discourse analysis reveals how, in this instance, the museum practices were primarily inherited from past traditions, and so failed to convey the meanings previously envisioned by the curators. In order for genuine public engagement with museum exhibitions about music, a collaboration is required between the music studies and museum studies professionals. Only through such a collaboration can it be ensured that those contemporary dynamics are present and meaningful.     

Intellectuals and intelligentsia in the pages of library periodicals

Analysis of the publications of the journals “Biblioteka” and “Nauchnye i tekhnicheskie biblioteki” helps to compare the value guidelines of modern library journals. As a result of the research, it has been revealed that the first journal adheres to the values of the intellectuals, and the second óne adheres to the values of the intelligentsia.     

Oryza sativa L. (Rice) in the Ancient Earthen Plasters of Painted Fragments from Bezeklik,China

ABSTRACT

This research reports for the first time the inclusion of Oryza sativa straw, root, and husk as a vegetal additive in the fifth century CE decorative mud plaster of the Buddhist cave of Bezeklik. The investigation is based on the morphological, anatomical, and silica bodies study of the vegetal additives accomplished through a light microscope, stereomicroscope, Fourier-transform infrared spectrophotometer, and scanning electron microscope from the isolated fragments of the painted plaster, transported to India in the nineteenth century and presently housed in National Museum, New Delhi. Studies indicate that loamy sand soil sourced locally for the earthen plaster was mixed with paddy straw in the proportion of 25–30% by volume for cohesion and strength. The excess of sand and absence of clay-size particles in plaster is, however, causing disaggregation of the grains due to lack of cohesion. As locally available materials are preferably used for any plaster works, this study also raises the question – was ancient Bezeklik, now a desert of Northwest China, once a rice-growing area in addition to the crops of Triticum aestivum (wheat), Setaria italica (Foxtail millet), and Hordeum vulgare (barley) reported by many researchers, based on hypothetical environment recreation. This study will help prepare a compatible plaster for the restoration of fragile-painted plaster fragments.     

Study and Conservation of the St. Nicola's Basilica Mosaics (Bari,Italy) by Photogrammetric Survey: Mapping of Polychrome Marbles,Decorative Patterns and Past Restorations

ABSTRACT

This present work focuses on the mapping of marbles, decorative patterns and area of the mosaics of the St. Nicola’s Basilica in Bari (Italy) by their photogrammetric survey. The extraordinary importance of these mosaics is due to the stylistic uniqueness and the undisputed workmanship and to the employed materials for tesserae. These mosaics include the white and polychrome marbles, used in the Roman age and reused in medieval artistic production, and imitation stones used as substitutes during the past restorations. The digital survey was realised by the photogrammetric reconstruction of mosaics collecting a photo dataset, after the mosaics redrawing by an image processing software and finally implemented it with lithological identification marbles. It allowed to obtain a punctual mapping of materials, through which to identify original areas and restoration areas, decorative patterns, recurring geometries. The research carried out, supported by the photogrammetric reconstruction as established method for high resolution digital reproduction and mapping, not only ensures the conservation and improvement of the enjoyment of the mosaic floors of the St. Nicola’s Basilica, but allows to conduct studies on materials, decorative patterns and restoration areas directly on the digitized product.     

Issues Related to the Restoration of Mirrors of the Wooden paliotto della chiesa del Santissimo Crocifisso all’Albergheria,Sicily (Italy)

In this work, the decision-making process involved in the restoration of the eighteenth century paliotto ligneo (wooden altar frontal) della chiesa del Santissimo Crocifisso all’Albergheria of Palermo is presented. Earlier research concerning mirror restoration was based on only a few case studies and the proposed techniques were not suitable for the artwork here. As a consequence, it was necessary to re-examine theories and protocols of modern restoration to plan an appropriate intervention of the altar frontal. Since in this artwork the role of mirrors is not to give back images, as usual, but rather to create special light effects and play of lights, this work aims to find an approach to the restoration of the altar frontal and its decorations that allows a homogeneous overview of the piece. Thus, the mirrors were not substituted or re-created. Only a visual integration of the damaged ancient mirrors was proposed, with the use of metallic-polymeric films, permitting a completely reversible restoration.     

Unveiling the Colours of Cellulose Nitrate Black and White Film-based Negatives in Colonial Photography

ABSTRACT

Aiming at contributing to the preservation of black and white (B&W) film-based negatives held by Portuguese archives, four photographic collections from the first half of the twentieth century were selected for study. During the macro assessment of the collections the preservation condition and hues found in photographic negatives from the Elmano Cunha e Costa (ECC) were noticed, distinguishing this collection from the remaining ones. Additional attention was given considering that the ECC collection was formed in a colonial context in the 1930s, while the others were formed on the Portugal mainland. The ECC collection results from an ethnographic survey of Angolan tribes recorded with B&W film-based negatives. In this collection, sets of negatives with pink, lemon yellow, greenish, orange brownish, and red brownish hues were found. To identify the origin of such hues, the image layer was analysed by microscale energy-dispersive X-ray fluorescence (μ EDXRF) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX). Additionally, to assess the base decay and its effect on the formation of hues, the plastic supports were characterized by Fourier transform infrared microscopy (μ FTIR). To complement the assessment of the film-base decay, pH was measured by using combined microelectrodes. The identification of mercury, iodine, chromium, and iron by μ EDXRF allowed correlation of the hues found in the negatives with chemical corrective treatments performed to improve the image quality. SEM-EDX confirmed those results and proved that the elements found were in the photographic emulsion layer. The results obtained are relevant since the hues identified may now be used as markers to indicate the technical work performed on colonial photography. Additionally, the visual and molecular assessment of the negatives’ supports (good to fair condition) allow proposing that the original storage conditions may have had a beneficial contribution to their present condition.     

Taking a Closer Look at the Factors That Influence Ethnic Identity

Ethnic identity (EI) has long been known to supersede race as a predictor for attitudes and behaviors. However, little is known about the constituent parts that comprise and influence ethnic identity. In order to improve communications that target EI, we examine both demographic and communication variables to determine which have a greater pull on people’s attitudes and actions. Race appears to moderate the effects of age on ethnic identity, whereby age was negatively related to ethnic-identity exploration among White participants and positively related to ethnic identity commitment among Black participants (p < .05). Having a higher income, print-media use, and information-engagement orientation were also positively correlated with ethnic identity; education and gender were not. Implications and future directions are discussed.