Uso da tomografia de raios X no estudo da pedra utilizada em edifícios

A seguinte tese de doutoramento está livremente disponível aqui:

Veerle Cnudde, Exploring the Potential of X-ray Tomography as a New Non-destructive Research Tool in Conservation Studies of Natural Building Stones, Ghent, Ghent University, 2005.

Resumo:

The mean purpose of this study was primarily the exploration of the possibilities of the non-destructive X-ray micro-CT technique in the domain of conservation and restoration of natural building stones. Special attention was paid to more specific topics like visualization of conservation products inside natural building stones, determination of porosity and pore-size distribution of scanned samples and monitoring of artificial weathering processes. Additionally the influence of conservation products on the original properties of stone material was also studied. High-speed neutron tomography was introduced as a new non-destructive visualisation technique and tested for its potential in fluid-flow research inside building materials.

A encolagem de gelatina e o seu impacto na degradação da celulose do papel

A seguinte tese de doutoramento está livremente disponível aqui:

Anne-Laurencee Dupont, Gelatine Sizing of Paper and Its Impact on the Degradation of Cellulose During Aging. A Study Using Size-exclusion Chromotography, Amsterdam, Universiteit van Amsterdam, 2003.

Resumo:

The issue of permanence and durability of paper is one of the major concerns in cellulose research and paper conservation. From the perspective of conservation research, the understanding of the long-lasting properties of paper begins with the investigation of the characteristics of papers in good physical condition that have best survived the passage of time. In European papermaking history, this is the case with early papers, which for the most part, present far better state of conservation than papers of more recent origins. Several facets that could explain the longevity and stability of paper have been investigated in the past, but one that has been largely neglected to date is the process of sizing. Papers dating from the fourteenth to the eighteenth centuries, in addition to having been fabricated from good quality fibres which partly explains their durability, have also inn common that they were sized almost systematically with gelatine. The present study is dedicated to the investigation of the role of gelatine in pure cellulose paper. The research is approached mainly from the angle of polymer chemistry. The impact of gelatine sizing upon aging on the molecules of cellulose, and the changes incurred by varying the sizing material are studied. The analytical technique selected is size-exclusion chromatography (SEC), which is employed in the characterisation of both cellulose and the gelatine, and in thee investigation of their degradation upon aging. Model papers were fabricated for this purpose, but the study also includes the characterisation of naturally aged papers.

Identificação de aminoácidos por cromatografia gasosa e estudo de um ícone

A seguinte tese de mestrado foi agora livremente disponibilizada online:

Maria Vaz Pinto d’ Avillez, Part I : Comparing derivatization methods for amino acids – one and two-step procedures using gas chromatography – flame ion detector (GC-FID) Part II: Story of an icon from its execution until its conservation, Lisboa, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2008.

Está aqui.

Resumo:

Two derivatization methods were tested in twenty-one standard amino acids (AAs) for further identification and quantification by the analytical technique of Gas Chromatography with Flame Ion Detector (GC-FID). For the one-step derivatization reaction N-methyl-N (tert.- butyldimethylsilyl)trifluoroacetamide (MTBSTFA) was used and for the two-step reaction we used hydrochloridic acid (HCl) and trifluoroacetic anhydride (TFAA). We obtained better results with the derivatization procedure in two-steps, although it takes longer, and we concluded that the reproducibility of these reactions is difficult to achieve.

Análise de uma pintura atribuída a Van Eyck

A seguinte dissertação de mestrado está livremente acessível aqui:

Hugh Hudson, Re-examining Van Eyck: a New Analysis of the Ince Hall Virgin and Child, Melbourne, The University of Melbourne, 2001.

Resumo:

The Ince Hall Virgin and child is a painting of the Virgin and Child in an interior that was attributed to Jan van Eyck by the leading historians of early Netherlandish art from 1854 to 1956. Between 1956 and 1959 the work was subject to a technical and art historical analysis in Europe, in the re-classification of the work as a copy by a follower of Van Eyck, and possibly a forgery. Subsequently, a number of art historians have suggested that not even the composition of the work is Eyckian, and that the work is a pastiche based on Van Eyck’s paintings. Nevertheless, some authors have doubted the arguments for these reattributions. Some authors maintain the attributions to Van Eyck, and others suggest that the work may be a copy. This thesis is the first comprehensive critical reappraisal of the scientific and art historical analysis to be conducted.

In the first chapter it examines the provenance and bibliography of the work.

In the second chapter it examines published and unpublished documents relating to the technical analysis found in Melbourne, Brussels, London and Amsterdam, which have been brought together for the first time. It also contains an interpretation of the work’s infrared reflectography that was produced, for the first time, for this thesis. It is argued that, contrary to the 1950's analysis, there is no technical impediment to an attribution of the work to Van Eyck. Furthermore, technical analysis reveals numerous correspondences to Van Eyck’s works, in the pigments, paint layer structures, underdrawing style and pentimenti.

In the third chapter the relationship of the execution, composition and iconography to Van Eyck’s paintings is discussed. It is argued that the execution, composition and iconography are closely related to Van Eyck’s works.

In the fourth chapter the attribution of the work as an original painting of Van Eyck, a copy, a pastiche or a forgery is discussed. It is concluded that the balance of the available evidence suggests the attribution of the work to Van Eyck, or his studio, is justifiable. The possibility that the work is a free copy is not excluded, but is undermined by the numerous correspondences to Van Eyck’s materials and technique and its relationship to the versions of the composition by other artists.

Análise de pigmentos maias

A seguinte tese de doutoramento está livremente disponível aqui.

Rosemary Anne Goodall, Spectroscopic Studies of Maya Pigments, Brisbane, Queensland University of Technology, 2007.

Resumo:

The Maya of Central America developed a complex society: among their many achievements they developed a writing system, complex calendar and were prolific builders. The buildings of their large urban centres, such as Copan in Honduras, were decorated with painted stucco, moulded masks, carving and elaborate murals, using a range of coloured pigments. In this study the paints used on the buildings of Copan and some ceramic sherds have been investigated, non-destructively, using micro-Raman spectroscopy, micro-ATR infrared spectroscopy, environmental scanning electron microscopy with energy dispersive X-ray analysis (ESEM-EDX) and FTIR-ATR imaging spectroscopy. The paint samples come from four buildings and one tomb covering three time periods in the four hundred year history of Copan. The main pigment used in the red paint on these samples was identified as haematite, and the stucco as a mixture of calcite particles dispersed throughout a calcite-based lime wash stucco. The composition and physical nature of the stucco changed through time, indicating a refining of production techniques over this period. A range of minor mineral components have been identified in each of the samples including rutile, quartz, clay and carbon. The presence and proportion of these and other minerals differed in each sample, leading to unique mineral signatures for the paint from each time period. Green and grey paints have also been identified on one of the buildings, the Rosalila Temple. The green pigment was identified as a celadonite-based green earth, and the grey pigment as a mixture of carbon and muscovite. The combination of carbon and mica to create a reflective paint is a novel finding in Maya archaeology. The high spatial resolution of the micro-FTIR-ATR spectral imaging system has been used to resolve individual particles in tomb wall paint and to identify their mineralogy from their spectra. This system has been used in combination with micro-Raman spectroscopy and ESEM-EDX mapping to characterize the paint, which was found to be a mixture of haematite and silicate particles, with minor amounts of calcite, carbon and magnetite particles, in a sub-micron haematite and calcite matrix. The blending of a high percentage of silicate particles into the haematite pigment is unique the tomb sample. The stucco in this tomb wall paint has finely ground carbon dispersed throughout the top layer providing a dark base for the paint layer. Changing paint mixtures and stucco composition were found to correlate with changes in paint processing techniques and building construction methods over the four hundred years of site occupation.

Identificação de pigmentos por espectroscopia de infravermelho

Acabou de ser disponibilizada online a seguinte tese de doutoramento:

Signe Vahur, Expanding the Possibilities of ATR-FT-IR Spectroscopy in Determination of Inorganic Pigments, Tartu, University of Tartu, 2010.

Está aqui.

Resumo:

The present work focused on expanding the possibilities and usefulness of micro-ATR-FT-IR spectroscopy in identification of different inorganic pigments in historic artefacts. Most of the pigments used historically in paintings and other artefacts are inorganic compounds. ATR-FT-IR has found limited use for determination of inorganic pigments, because the mid-IR (4000–400 cm^–1) region of the IR spectrum of many of them is not characteristic enough and also there are many pigments that either do not absorb in that region at all (oxides, sulphides, etc) or have absorptions that are at the low wavenumber end of that region and are not characteristic enough for pigment identification. So, many pigment materials absorb IR radiation in the far-IR region (below 500 cm^–1). In contrast to the mid-IR region the far-IR region has traditionally been significantly less accessible for routine IR spectroscopic measurements. However, recent advances in instrument design have brought the wavenumber range below 500 cm^–1 well within reach of commercial FT-IR equipment. Nevertheless, this wavenumber region has up to now found almost no use in investigation of historic artefacts. In this dissertation 47 most widespread inorganic red, white, yellow, blue, green, brown and black pigments were examined. An analytical method for determination and identification of these inorganic pigments in paint layers by micro-ATR-FT-IR using the wavenumber region of 550–230 cm^–1 was developed. The advantages and limitations of the ATR-FT-IR and developed analytical method of the analysis of inorganic pigments in the low wavenumber were discussed. This work provides a comprehensive overview of the inorganic pigment identification possibilities using ATR-FT-IR as well as a collection of reference spectra in the low wavenumber range (550-230 cm^-1) and is expected to be a useful reference material for conservation practitioners and material scientists. The usefulness of ATR-FT-IR in the region of 550-230 cm^-1 for identification of inorganic pigments is demonstrated by 5 case studies on art objects (several of them are important in Estonian history).

Pedra natural para os monumentos históricos

Foi há pouco publicado o seguinte livro:

Richard Prikryl, Ákos Török (ed.), Natural Stone Resources for Historical Monuments, London, The Geological Society, 2010.

Índice:

• Richard Prikryl, Akos Torok, Natural stones for monuments: their availability for restoration and evaluation, pp. 1-9

• Heiner Siedel, Alveolar weathering of Cretaceous building sandstones on monuments in Saxony, Germany, pp. 11-23

• Gilles Fronteau, Celine Schneider-Thomachot, Edith Chopin, Vincent Barbin, Dominique Mouze, Andre Pascal, Black-crust growth and interaction with underlying limestone microfacies, pp. 25-34

• Matthieu Angeli, Ronan Hebert, Beatriz Menendez, Christian David, Jean-Philippe Bigas, Influence of temperature and salt concentration on the salt weathering of a sedimentary stone with sodium sulphate, pp. 35-42

• Swe Yu, Chiaki T. Oguchi, Is sodium sulphate invariably effective in destroying any type of rock?, pp. 43-58

• Chiaki T. Oguchi, Hayato Yuasa, Simultaneous wetting/drying, freeze/thaw and salt crystallization experiments of three types of Oya tuff, pp. 59-72

• Stephanie Gillhuber, Gerhard Lehrberger, Jurgen Goske, Fire damage of trachyte: investigations of the Tepla monastery building stones, pp. 73-79

• Dolores Pereira, Mercedes Peinado, Mariano Yenes, Serafin Monterrubio, Jose Nespereira, Jose Antonio Blanco, Serpentinites from Cabo Ortegal (Galicia, Spain): a search for correct use as ornamental stones, pp. 81-85

• Stephen McCabe, Bernard J. Smith, Patricia A. Warke, A legacy of mistreatment: conceptualizing the decay of medieval sandstones in NE Ireland, pp. 87-100

• Miguel Gomez-Heras, Bernard J. Smith, Heather A. Viles, Oxford stone revisited: causes and consequences of diversity in building limestone used in the historic centre of Oxford, England, pp. 101-110

• Kevin Beck, Muzahim Al-Mukhtar, Evaluation of the compatibility of building limestones from salt crystallization experiments, pp. 111-118

• Timo G. Nijland, Van Hees, Rob P. J., Laura Bolondi, Evaluation of three Italian tuffs (Neapolitan Yellow Tuff, Tufo Romano and Tufo Etrusco) as compatible replacement stone for Romer tuff in Dutch built cultural heritage, pp. 119-127

• Gioacchino F. Andriani, Nicola Walsh, Petrophysical and mechanical properties of soft and porous building rocks used in Apulian monuments (south Italy), pp. 129-141

• Michael Unterwurzacher, Ulrich Obojes, Roland Hofer, Peter W. Mirwald, Petrophysical properties of selected Quaternary building stones in western Austria, pp. 143-152

• Carlos Figueiredo, Rita Folha, Antonio Mauricio, Carlos Alves, Luis Aires-Barros, Contribution to the technological characterization of two widely used Portuguese dimension stones: the 'Semi-rijo' and 'Moca Creme' stones, pp. 153-163

• Marek Laho, Christoph Franzen, Rudolf Holzer, Peter W. Mirwald, Pore and hygric properties of porous limestones: a case study from Bratislava, Slovakia, pp. 165-174

• Aneta Stastna, Jan Jehlicka, Richard Prikryl, Raman spectra of reduced carbonaceous matter as a tool for determining the provenance of marbles: examples of 'graphitic' marbles from Czech quarries, pp. 175-183

• Lisa Cooke, The 19th century Corsi collection of decorative stones: a resource for the 21st century?, pp. 185-195

• Anna Frangipane, Working for an electronic database of historical stone resources in Friuli-Venezia Giulia (Italy), pp. 197-209

• Hana Kampfova, Richard Prikryl, Electronic database of historical natural stones of the Czech Republic: structuring field and laboratory data, pp. 211-217

• Francesco Allocca, Domenico Calcaterra, Gabriella Calicchio, Piergiulio Cappelletti, Abner Colella, Alessio Langella, Maurizio de' Gennaro, Ornamental stones in the cultural heritage of Campania region (southern Italy): the Vitulano marbles, pp. 219-231

A pedra calcária e o seu uso no património edificado

Foi há pouco publicado o seguinte livro:

B. J. Smith, M. Gomez-Heras, H. A. Viles, J. Cassar (ed.), Limestone in the Built Environment: Present-Day Challenges for the Preservation of the Past, London, The Geological Society, 2010.

Índice:

• Bernard J. Smith, Miguel Gomez-heras, Heather A. Viles, Underlying issues on the selection, use and conservation of building limestone, pp. 1-11

• Joann Cassar, The use of limestone in a historic context - the experience of Malta, pp. 13-25

• Jose P. Calvo, Manuel Regueiro, Carbonate rocks in the Mediterranean region - from classical to innovative uses of building stone, pp. 27-35

• Siegfried Siegesmund, Wolf-Dieter Grimm, Helmut Durrast, Joerg Ruedrich, Limestones in Germany used as building stones: an overview, pp. 37-59

• R. M. Espinosa-Marzal, G. W. Scherer, Mechanisms of damage by salt, pp. 61-77

• Ana Z. Miller, Nuno Leal, Leonila Laiz, Miguel A. Rogerio-Candelera, Rui J. C. Silva, Amelia Dionisio, Maria F. Macedo, Cesareo Saiz-Jimenez, Primary bioreceptivity of limestones used in southern European monuments, pp. 79-92

• E. Ruiz-Agudo, C. Rodriguez-Navarro, Suppression of salt weathering of porous limestone by borax-induced promotion of sodium and magnesium sulphate crystallization, pp. 93-102

• K. Beck, M. Al-Mukhtar, Weathering effects in an urban environment: a case study of tuffeau, a French porous limestone, pp. 103-111

• M. A. Stefanidou, Approaches to the problem of limestone replacement in Greece, pp. 113-117

• Kara R. Dotter, Historic lime mortars: potential effects of local climate on the evolution of binder morphology and composition, pp. 119-126

• Ioannou, M. F. Petrou, R. Fournari, A. Andreou, C. Hadjigeorgiou, B. Tsikouras, K. Hatzipanagiotou, Crushed limestone as an aggregate in concrete production: the Cyprus case, pp. 127-135

• Kevin Beck, Xavier Brunetaud, Jean-Didier Mertz, Muzahim Al-Mukhtar, On the use of eggshell lime and tuffeau powder to formulate an appropriate mortar for restoration purposes, pp. 137-145

• Z. Papay, A. Torok, Physical changes of porous Hungarian limestones related to silicic acid ester consolidant treatments, pp. 147-155

• C. Figueiredo, R. Folha, A. Mauricio, C. Alves, L. Aires-Barros, Pore structure and durability of Portuguese limestones: a case study, pp. 157-169

• C. Vazquez-Calvo, M. J. Varas, M. Alvarez De Buergo, R. Fort, Limestone on the 'Don Pedro I' facade in the Real Alcazar compound, Seville, Spain, pp. 171-182

• C. Figueiredo, L. Aires-Barros, M. J. Neto, The church of Santa Engracia (the National Pantheon, Lisbon, Portugal): building campaigns, conservation works, stones and pathologies, pp. 183-193

• O. Buj, J. Gisbert, B. Franco, N. Mateos, B. Bauluz, Decay of the Campanile limestone used as building material in Tudela Cathedral (Navarra, Spain), pp. 195-202

• S. Rescic, F. Fratini, P. Tiano, On-site evaluation of the 'mechanical' properties of Maastricht limestone and their relationship with the physical characteristics, pp. 203-208

• D. E. Searle, D. J. Mitchell, The effect of combustion-derived particulates on the short-term modification of temperature and moisture loss from Portland Limestone, pp. 209-218

• Derek Mottershead, Paul Farres, Alastair Pearson, The changing Maltese soil environment: evidence from the ancient cart tracks at San Pawl Tat-Targa, Naxxar, pp. 219-229

• Mary J. Thornbush, Measurements of soiling and colour change using outdoor rephotography and image processing in Adobe Photoshop along the southern facade of the Ashmolean Museum, Oxford, pp. 231-236

• O. Sass, H. A. Viles, Two-dimensional resistivity surveys of the moisture content of historic limestone walls in Oxford, UK: implications for understanding catastrophic stone deterioration, pp. 237-249

Conservation Perspectives - The GCI Newsletter, vol. 25, n.º 1, 2010

Já há alguns dias que foi publicado o 1.º número de 2010 da revista Conservation Perspectives - The GCI Newsletter. Está livremente disponível aqui.

Índice:

• Karen Trentelman, Collections Research: A Combined Approach to the Study of Works of Art, p. 5

• Marco Leona, Collections Research: Research at the Interface of Science and Art, p. 8

• Katherine Eremin, Marc Walton, Collaborations in Archaeological Science: Analysis of Glass from Nuzi, Mesopotamia, p. 10

• Christine Sciacca, Catherine Schmidt Patterson, Examining the Connections: Collaborative Research of Early Renaissance Workshop Practice, p. 13

• David Carson, Giacomo Chiari, New Technologies in the Service of Cultural Heritage, p. 16

e-Conservation, n.º 14, 2010

Há poucos dias ficou livremente disponível online a revista e-Conservation, n.º 14, de 2010. Está aqui.

Além das habituais secções de notícias e recensões, contém os seguintes artigos:

• Cornelia Sãvescu, Dinu Sãvescu, Conservation-Restoration Interventions in Extreme Cases. Improving the Structural Resistance of Wood Damaged by Biological Attack, p. 30

• Lino García, Pilar Montero Vilar, The Challenges of Digital Art Preservation, p. 43

• Frederico Henriques, Ana Bailão, Miguel Garcia, The Conservation-Restoration of the "Charola" Paintings of the Convent of Christ in Tomar, p. 54

• Élia Roldão, Luís Pavão, The Conservation and Preservation of a Photographic Print. The "Panoramic View of Constantinople", p. 70

Conservação de uma obra de alta costura

Foi há pouco colocada online a seguinte tese de mestrado:

Marta Teixeira Vieira, O Casaco Dourado de Jean Paul Gaultier (n.1952-): Conservação de Alta Costura (MUDE - Colecção Francisco Capelo), Lisboa, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2009.

Está livremente disponível aqui.

Resumo:

Pretendeu-se com esta investigação conservar o casaco dourado de alta costura criado por Jean Paul Gaultier (Arcueil, n.1952), que faz parte da colecção Francisco Capelo, actualmente integrada no MUDE – Museu do Design e da Moda (Lisboa, Portugal). Para conservar esta obra realizou-se um estudo histórico-técnico-artístico procurando preservar os valores e funcionalidade da obra. Este é um estudo inovador na conservação de têxteis contemporâneos dado que esta é uma obra complexa de grande singularidade e composta por uma grande diversidade material e procurou-se conhecer os materiais, a intenção criativa de Gaultier e os processos de degradação da sua obra. Para tal, recolheu-se informação sobre o casaco e a alta costura do criador em inquéritos à Casa Gaultier (Paris), entrevista ao coleccionador, através de contactos com diversos museus internacionais, e recorrendo a bibliografia e vídeos sobre os desfiles do criador. O estudo do casaco e das causas da sua degradação requereu uma caracterização material detalhada, para a qual se recorreu a diversas técnicas de exame e análise como a microscopia óptica (M.O), radiografia, a µ-EDXRF, a espectroscopia de FTIR, a HPLC-DAD-MS e ainda ICP-AES, o que permitiu delinear um plano de conservação adequado. Este plano incluiu medidas de conservação preventiva do casaco, a consolidação de elementos decorativos e o estudo de possíveis filmes protectores para a peça, testando nano filamentos de silicone e revestimentos de sílica produzidos pelo método sol-gel. O estudo aqui apresentado permitiu minimizar a perda de elementos decorativos da obra e testar formas de reduzir a degradação futura do forro. Permitiu ainda obter filmes hidro-repelentes e bastante homogéneos que poderão ser uma protecção futura adequada para o casaco, sendo apenas necessário testar a longevidade dos filmes obtidos em réplicas para garantir a conservação a longo prazo da obra.

Estudo da degradação de óleos secativos de tintas do século XIX

Acabou de ser disponibilizada online a seguinte tese de mestrado:

Joana Cristina Vaz Pedroso, Estudo da Degradação de Óleos Secativos, em Tintas de Amadeo de Souza-cardoso, Silva Porto e Gustave Courbet, Lisboa, Faculdade de Ciências e Tecnologia da Universidade Nova de Lisboa, 2009.

Está aqui.

Resumo:

Neste trabalho foi feito o estudo da degradação de tintas de óleo e da influência dos pigmentos e cargas na sua degradação. Os casos de estudo são tintas envelhecidas naturalmente, recolhidas da paleta de Silva Porto, da tela “Floresta Fechada” do pintor Gustave Courbet, e ainda dos tubos de tinta de Amadeo de Souza-Cardoso. Dado a cronologia de vida destes artistas, foi permitido estudar a evolução da degradação de um óleo secativo num período de 150 a 100 anos, até hoje. Foi verificada a existência de um padrão de degradação, que se traduz na formação de ácidos carboxílicos e sabões metálicos. O ião chumbo apresenta o maior poder catalisador na formação destes produtos de degradação. Este estudo foi feito por µ-Espectroscopia de Infravermelho por Transformada de Fourier, usando a 2ª derivada como método adicional, o que facilitou a interpretação de dados. Foi ainda feita a caracterização molecular de algumas cores da tela “Floresta Fechada” do pintor francês Gustave Courbet, e finalmente um estudo da composição de pigmentos ocre, que provou ser bastante útil no estudo da degradação das tintas de óleo.