Variedades e estilos na obra atribuída a Frei Carlos: novas perspetivas

Este trabalho de investigação centra-se no contributo dos exames de superfície e nas análises micro-analíticas no estudo de vinte e uma pinturas atribuídas à oficina de Frei Carlos, um dos grandes Mestres Luso-Flamengos ativos em território Nacional durante a primeira metade do século XVI. A "Pintura Luso-Flamenga" é uma expressão comummente usada na história da pintura Portuguesa do primeiro terço do século XVI e no seu sentido mais básico designa o trabalho de mestres flamengos que se instalaram em Portugal durante o reinado de D. Manuel I (1495- 1521) contribuindo decisivamente para o processo de renovação da pintura Portuguesa na época. O estudo integrado combina a pesquisa histórica em fontes documentais com exames de superfície e de caracterização material das obras de arte. O estudo material das pinturas foi realizado através de microscopia ótica, microscopia de infravermelhos com transformada de Fourier, espectroscopia de micro-Raman, microscopia eletrónica de varrimento acoplada com espectrometria de energia dispersiva de raios X, micro- difração de raios-X, cromatografia líquida de alta eficiência e pirólise acoplada à cromatografia gasosa /espectrometria de massa. Esta investigação envolveu técnicas complementares de análise de superfície e de ponto no estudo técnico e material das preparações, imprimitura, desenho subjacente, camadas pictóricas e sucessões estratigráficas, dando a conhecer os materiais utilizados na execução técnica das pinturas e evidenciando especificidades técnicas da produção artística. Este estudo pretende inclusivamente evidenciar alguns detalhes técnicos do artista que possivelmente estão relacionados com a herança das práticas Flamengas. O conhecimento de algumas particularidades da técnica deste Mestre também permitiu estabelecer comparações com duas pinturas que haviam sido atribuídas, com algumas reservas, a esta oficina de pintura Luso-Flamenga. Mais recentemente, como resultado de um estudo colaborativo, foi realizada uma ampla campanha de reflectografia infravermelhos, introduzindo novos dados acerca da execução técnica do desenho subjacente, o que contribuiu para diferenciar, nestas duas pinturas, outra "mão", atribuída então a um seguidor de Frei Carlos. Esta investigação introduz um novo e profundo conhecimento sobre a Oficina de Frei Carlos, permitindo estabelecer comparações com a obra do seu seguidor e com uma pintura também atribuída a esta oficina e que incorpora o Museu da National Gallery (NG5594), evidenciando os materiais utilizados na técnica de produção artística e especificidades técnicas aliadas aos processos criativos/ construtivos que permitem estabelecer os pontos de contacto e de diferenciação entre estas obras; Varieties and styles in the works attributed to Frei Carlos - new perspectives Abstract: This investigation is focused on the contributions of surface exams and micro-analytical research in the study of twenty one paintings attributed to Frei Carlos workshop, one of the most important Portuguese-Flemish painters active in our country during the first half of sixteen Century. "Portuguese-Flemish Painting" is a common expression used in the history of Portuguese painting of the first third of the sixteenth century and in its most basic meaning designates the work of Flemish masters who settled in Portugal during the reign of King Manuel I (1495-1521) contributing decisively to the process of renewal of Portuguese painting at the time. The integrated approach combines historical research on documental sources with surface examination and material characterization of the paintings by using state-of-art analytical techniques. Microanalysis was carried out by optical microscopy, micro-Fourier-transform infrared-spectroscopy, micro-Raman spectroscopy, scanning electron microscopy coupled with energy dispersive X-ray spectrometry, micro-X-ray diffraction analysis, high performance liquid chromatography and Pyrolysis gas chromatography mass spectrometry. This complementary surface and analytical research was involved in the technical and material characterization of grounds, underdrawings, primings, paint layers and its multi-layered build-up, providing access to the painter´s materials used in the technical execution of the paintings and details of the technique of artistic production. This study also intends to expose some usual details of the artist’s technique which are possibly related to the Master´s Flemish influence. The knowledge of some particularities of the Master´s technique also allowed a new comparison with two paintings that had been attributed with some reserves to this Portuguese-Flemish workshop. More recently, as a result of a collaborative study, an extensive infrared reflectography campaign was made, giving new data concerning underdrawings technical execution and contributing to differentiate, in these two paintings, another “hand”, attributed to a follower of Frei Carlos. Complementary analytical research also added a new and deep insight into Frei Carlos workshop, his follower and a panel that still attributed to Frei Carlos workshop that integrates the National Gallery´s Museum (NG5594), evidencing the materials used in technical production, their models and sources of artistic inspiration, techniques and pictorial construction procedures that could specifically relate or distinguish between them.

José de Escovar at the Chapel of the Souls: Technical and Material Study of a 1603 Panel Painting

This article reports the preliminary results of a technical and material study carried out on a 17th century panel painting located at the Chapel of the Souls in the main church of Vila Nova da Baronia (30 km away from Evora city, in southern Portugal). This painting is attributed to Jose the Escovar, a painter that worked for Evora Archiepiscopate between 1583 and 1622. Jose the Escovar is known by his mural paintings all across the Alentejo region. This is the first time that a panel painting made by this artist was studied. Analytical methods used included in situ technical photography (visible (Vis), raking light (RAK), infrared (IR), and ultraviolet (UV)), optical microscopy of cross sections, scanning electron microscopy with energy dispersive X-ray spectrometry (SEM-EDS), micro Raman spectroscopy, and micro Fourier transform infrared spectroscopy (m-FT-IR). The goal was to ascertain the techniques and colored materials used by Escovar on this painting so that the data can be used in future comparisons with others works attributed to this painter based on stylistic aspects.

New insight on the underdrawing of 16th Flemish-Portuguese easel paintings by combined surface analysis and microanalytical techniques

This paper focusses on the study of the underdrawings of 16th century easel paintings attributed to the workshop of the Portuguese-Flemish Master Frei Carlos. This investigation encompasses multidisciplinary research that relates the results of surface exams (infrared reflectography, standard light photography and infrared photography) with analytical investigations. The surface analysis of Frei Carlos’ underdrawings by infrared reflectography has shown heterogeneous work, revealing two different situations: (1) an abundant and expressive underdrawing, revealing a Flemish influence and (2) a simple and outlined underdrawing. This preliminary research raised an important question related to this Portuguese-Flemish workshop and to the analytical approach: Is the underdrawing's heterogeneity, as observed in the reflectograms, related to different artists or is this rather an effect that is produced due to the use of different materials in the underdrawing's execution? Consequently, if different materials were used, how can we have access to the hidden underdrawings? In order to understand the reasons for this dissemblance, chemical analysis of micro-samples collected in underdrawing areas and representing both situations were carried out by optical microscopy, micro Fourier transform infrared spectroscopy (μ-FTIR), scanning electron microscopy coupled with energy dispersive X-ray spectrometry (SEM-EDX) and micro-Raman spectroscopy (μ-Raman). Taking into account the different possibilities and practical and theoretical limitations of surface and punctual examinations in the study of easel painting underdrawings, the methodology of research was adjusted, sometimes resulting in a re-analysis of experimental results. This research shows the importance of combining multispectral surface exams and chemical analysis in the understanding of the artistic creative processes of 16th century easel paintings.

Preparação, caracterização e modificação de adsorventes para remoção de pesticidas de águas

O objectivo principal deste trabalho de mestrado consistiu em avaliar a potencial utilização de materiais adsorventes, nomeadamente, de carvões activados (AC) preparados por activação química com KOH, a partir de PET reciclado, e de materiais com estrutura mesoporosa ordenada, do tipo MCM-41 e SBA-15, na remoção de ácido 4 - cloro - 2 - metilfenoxiacético (MCPA) e de azul de metileno (MB), presentes nas águas. Nesta tese apresentam-se estudos de preparação e caracterização de materiais micro e mesoporosos e também estudos de avaliação da capacidade adsortiva em fase líquida. Prepararam-se três materiais microporosos, nomeadamente, PET-2-700, PET-2-700ox (AC oxidado) e PET-2-700red (AC reduzido), dois materiais constituídos exclusivamente por mesoporos, Si-MCM-41 e Ti-MCM-41-50 e dois materiais contendo maioritariamente mesoporos, mas que também possuem alguma microporosidade, tais corno, Si-SBA-15 e Ti-SBA-15-50. A caracterização textural dos adsorventes foi inferida por adsorção de azoto a 77K e por de difracção de raios X. Recorreu-se a três métodos de análise das isotérmicas, nomeadamente, Dubinin-Radushkevich, Brunauer-Ernrnett-Teller e alfa-s (as). A caracterização química dos AC foi realizada recorrendo-se a técnicas de análise elementar (AE) e espectroscopia de infravermelho com transformadas de Fourier (FTIR) e à determinação do ponto de carga zero. Os três carvões activados possuem valores de área superficial externa idênticos, o PET-2-700 possui o maior volume microporoso e o PET-2-700ox exibe o maior diâmetro de poros. Por outro lado, o PET-2-700ox possui um carácter fortemente ácido, o PET-2-700 exibe carácter ligeiramente ácido e o PET-2-700red apresenta propriedades ligeiramente alcalinas. Com base na AE, todas as amostras possuem percentagens de carbono elevadas, sendo que o PET-2-700red apresenta o valor mais elevado. Os resultados obtidos para a caracterização estrutural dos revelaram a obtenção de materiais mesoporosos de alta qualidade, definida pela elevada regularidade e uniformidade da estrutura porosa. A análise dos parâmetros de caracterização textura! permitiu inferir que os quatro materiais mesoporosos possuem valores de área superficial elevados, e que os materiais SBA-15 apresentam valores de volume poroso total e de tamanho de poros superiores aos manifestados pelos MCM-41. A incorporação de titânio não conduziu a uma perda significativa de qualidade dos materiais substituídos em relação às correspondentes amostras de sílica. Efectuaram-se estudos de adsorção em fase líquida de forma a avaliar a possível aplicação dos vários adsorventes na remoção de MCPA e de MB de efluentes líquidos. concluiu-se que o tempo de equilíbrio de 72 horas seria adequado e que a capacidade de adsorção dos vários AC era superior em meio ácido. Com base nas isotérmicas de adsorção do MCPA e do MB e na aplicação da representação de Langmuir e de Freundlich, foi possível concluir que o PET-2-700 possui a maior capacidade de adsorção do MCPA, 1.42 mmol/g, enquanto que o PET-2-700ox revelou a maior capacidade de adsorção do MB, 1.43 mmol/g. Na realidade, os materiais microporosos estudados apresentaram percentagens de remoção elevadas, tanto do MCPA como do MB. Relativamente aos materiais mesoporosos ordenados preparados neste trabalho, a percentagem de remoção de para os poluentes em estudo foi relativamente baixa, constatando-se que nesta fase dos estudos não constituem uma alternativa viável à utilização dos AC. No entanto, uma funcionalização criteriosa dos mesmos pode eventualmente proporcionar um aumento da capacidade adsortiva. ABSTRACT: The work presented in this master thesis, consisted of evaluating the potential use of different adsorbents materials, like activated carbon (AC) prepared by chemical activation with KOH, from recycled poly (ethylene terephthalate) (PET) and materials with ordered mesoporous structure such as MCM-41 and SBA-15, for removing acid 4-chlorine-2-metilfenoxiacétic and methylene blue from aqueous phase. We had prepared three microporous materials, PET-200-700, PET-2-700ox (AC oxidized) and PET-2-700red (reduced AC), two materials consisting exclusively of mesopores, Si-MCM-41 and Ti-MCM-41-50 and two materials containing mainly mesopores, but also having some microporosity, such as Si-SBA-15 and Ti-SBA-15-50. The textural characterization of the adsorbents was inferred by nitrogen adsorption at 77K and X-ray diffraction. Three methods were used to analyse the isotherms, namely, Dubinin-Radushkevich, Brunauer-Emmett-Teller and alpha-s (as). The chemical characterization of AC was performed using the elementary analysis, Fourier transform infrared spectroscopy (FTIR) and determination of the point of zero charge. Concerning the AC, the three present almost the same externa! surface area, PET-2-700 has a high micropore volume and PET-2-700ox shows the largest pore size diameter. On the other hand, PET-2-700ox had a strong acid character, PET-2-700 exhibits just a slightly acid character and PET-2-700red presents alkaline properties. The AE analysis allows confirming the high carbon content of theses AC, with PET-2-700red exhibiting the highest carbon proportion. The results from the structural characterization of the mesoporous materials, had disclosed the attainment of materials with high quality, defined by the raised regularity and uniformity of the porous structure. The analysis of the textural parameters allowed inferring that the four studied mesoporous materials possess high superficial area. The SBA-15 type materials present higher values of total porous volume and pores size diameter as the MCM-41. Also, the titanium incorporation did not lead to a significant loss of quality of the materials substituted in relation to the corresponding silica samples. The adsorption studies in liquid phase allow evaluating the possibility of using the different adsorbents for the MCPA and the MB removal. The kinetic studies had allowed to state the equilibrium time as 72 hours and a higher adsorption capacity was achieved in an acid medium. The influence of the pH of the medium, on the MCPA adsorption was evaluated. The MCPA and MB isotherms were analysed based on the Langmuir and Freundlich equation, the representations presented an excellent linearity, indicating the applicability of these equations to these systems. Also, it allows concluded that PET-2-700 had a higher adsorption capacity for MCPA, 1.42 mmol/g, and PET-2-700ox had a higher adsorption capacity for MB, 1.43 mmol/g. The AC used presented high removal percentages for MCPA and MB. Concerning the mesoporous materials prepared in this work, the percentage removal for the pollutants in study was relatively low, and evidencing that at the moment these mesoporous materials do not constitute a viable alternative to the AC. However, an astute funcionalisation of the same ones can, eventually provide an increase of the adsorption capacity.

Calcium sulfate fillers and binders in Portuguese 15th and 16th centuries: Ground layers from a family painting workshop — Study by multianalytical spectroscopic techniques

This study presents results on a developed methodology to characterize ground layers in Portuguese workshops. In this work a set of altarpieces of the 15th and 16th centuries, assigned to Coimbra painting workshop was studied, overall the masters Vicente Gil (doc. Coimbra 1498–1525), Manuel Vicente (doc. Coimbra 1521–1530) and Bernardo Manuel (act. c. 1559–94), father, son and grandson, encompassing from late gothic to mannerist periods. The aim of the study is to compare ground layers, fillers and binders of Coimbra workshop, and to correlate their characteristics to understand the technical evolution of this family of painters, using complementary microscopic techniques. The cross-sections from the groups of paintings were examined by optical microscopy and the results were integrated through the analysis obtained by μ-X–ray diffraction, scanning electron microscopy with energy dispersive X–ray Spectrometry, μ-confocal Raman and occasionally with μ-Fourier transform infrared spectroscopy imaging. Ground layers are of calcium sulfate, present as gesso grosso (mainly anhydrite with small amounts of gypsum) in the first and last phases of the workshop and gesso mate (mainly gypsum with small amounts of anhydrite) in an intermediate period. Binders have protein and oleic characteristics.

Analytical evaluation of paper degradation

The aim of this work was in first place to define a methodology for the use of Py-GC/MS as a characterization technique for the organic compounds present in paper samples containing foxing stains, paper have a complex structure and mostly consist with cellulose fibers. Additionally, it was intent to characterize paper samples containing foxing stains with a batch of non-destructive analytical techniques. The work intent to deepen our knowledge on foxing stains, its chemical nature and morphological aspects. For characterization of the morphology of paper samples and foxing stains was used photography under different illuminations and optical microscopy. The presence of fibers disruption was observed with scanning electron microscopy coupled with energy dispersive spectroscopy (SEM-EDS), and also the nature of the fillers that is present in different areas. Attenuated total reflection Fourier transform infrared spectroscopy (ATR-FTIR) was used for identification of the sizing agents, determination of the chemical composition of additives that were used for production of paper, and comparison between foxing stains and unfoxed areas was allowed. Micro X-ray diffraction was used to evaluate the crystalline fillers in the sample. Pyrolysis-Gas Chromatography/Mass Spectrometry (Py-GC/MS was used for chemical analysis to identify the organic components and different classes of organic compounds; Resumo: O objetivo deste trabalho foi definir, em primeiro lugar, uma metodologia para o uso de Py-GC / MS como técnica de caracterização dos compostos orgânicos presentes em amostras de papel contendo manchas de foxing, o papel tem uma estrutura complexa e consiste principalmente com fibras de celulose. Além disso, pretendia caracterizar amostras de papel contendo manchas de raposas com técnicas analíticas não destrutivas. Para a caracterização da morfologia das amostras de papel e das manchas de foxing foi usada fotografia sob diferentes iluminações e microscopia óptica. A presença de fibras de ruptura foi observada por microscopia electrónica de varrimento juntamente com espectroscopia dispersiva de energia (EDS-SEM), assim como a natureza dos materiais de enchimento que está presente em diferentes áreas. Espectroscopia de infravermelho com transformada de Fourier em modo de reflexão total atenuada (ATR-FTIR) foi utilizada na identificação dos agentes de colagem, e na determinação da composição química de aditivos usados na produção de papel, e a comparação entre foxing manchas e áreas unfoxed foi deixada. Micro difracção de raios X foi usada para avaliar o enchimentos cristalinos na amostra. Cromatografia pirólise-gasosa / espectrometria de massa (Py-GC / MS) foi utilizada para análise química para identificar os componentes orgânicos e diferentes classes de compostos orgânicos.