The origins of materials and practices – A review

UID/QUI/50006/2013. POCI-01-0145-FEDER-007265This paper is the fifth of a series and focuses on tracing the history of the use of gypsum based products as well as of the use of ground layers, centred on a review of published analytical evidence. The purpose is to contribute for the understanding of these long traditions which led to the choice of specific materials and practices used for producing gilding grounds in southern Europe. In fact, several practices and the raw material gypsum used in gilded surfaces do have an extremely long tradition, which can be traced back to the Pre-Pottery Neolithic B. The systematic use of these materials, especially the use of ground layers for decoration and other purposes, suggests not only an intention but also, somehow, the notion of a complex concept, the concept of a composite material, even at these very early periods, from which gilding origins. In addition, the particular case of Portugal shows that aspects such as religious, political, and sociocultural influences played a central role in the choice of gypsum as the raw material, which was curiously used exclusively for gilding.publishersversionpublishe

Monitoring the Natural Heating of Two Art Nouveau Glass Windows by Infrared Thermography

UID/EAT/00729/2019 SFRH/BPD/108403/2015publishersversionpublishe

Impact of solar radiation and environmental temperature on Art Nouveau glass windows

Fundacao para a Ciencia e Tecnologia of Portugal (Project Ref. UID/EAT/00729/2019). Fundacion General CSIC of Spain (ComFuturo Programme). We also acknowledge support of the publication fee by the CSIC Open Access Publication Support Initiative through its Unit of Information Resources for Research (URICI).This work presents the results of the evaluation of two Art Nouveau glass windows from the Casa-Museu Dr. Anastácio Gonçalves (Lisbon, Portugal) with IR-thermography during the summer solstice. According to the measurements, the surface temperature of glass depended on the outdoor environmental temperature and, mainly, on the direct solar radiation. Colored glasses presented a higher surface temperature due to the absorption of their chromophores at near-IR wavelengths. Enamels and grisailles showed higher surface temperatures than their support glasses due to both their chemical composition and color. The protective glazing, with small slits in one of the window panels, induced a hot-air pocket in its upper part due to the insufficient ventilation.[Figure not available: see fulltext.]publishersversionpublishe

Earth mortars stabilization: A review

A terra como material de construção tem sido alvo de um renovado interesse por se enquadrar nas actuais preocupações ambientais e de eco-eficiência. De facto, é um material ecológico e economicamente eficiente, revelando também propriedades de optimização do conforto no interior de edifícios. As argamassas de terra apresentam, no entanto, uma limitação: a sua susceptibilidade à água. De forma a viabilizar a sua utilização de forma mais abrangente, em ambientes interiores e exteriores onde possa existir contacto com água, tem vindo a ser estudada a inclusão de agentes estabilizantes. Neste artigo apresenta-se uma revisão critica do efeito de estabilizantes mais comuns utilizados em argamassas de terra, nomeadamente: fibras vegetais; ligantes tais como sulfatos de cálcio, cais aéreas e cais com propriedades hidráulicas, cimento; e óleos. Verifica-se que alguns destes estabilizantes parecem melhorar a resistência da terra à água líquida. No entanto, na maior parte das vezes, essa melhoria ocorre em detrimento de outras propriedades importantes, que são também discutidas.publishersversionepub_ahead_of_prin

An Investigation into the Suitability and Stability of a New Pigmented Wax-Resin Formulation for Infilling and Reintegration of Losses in Paintings

Publisher Copyright: © 2023 The Author(s). Published by Informa UK Limited, trading as Taylor & Francis Group.A new Pigmented Wax-Resin (PWR) formulation for infilling and reintegration of losses in paintings is introduced and tested for its suitability and stability. It consists of a mixture of Cosmoloid H80 microcrystalline wax and Regalrez 1126 hydrogenated hydrocarbon resin with dry pigments and/or fillers. Unlike other PWR formulations, including those sold by Gamblin Conservation Colors, it does not contain beeswax. Beeswax is reported to develop bloom and to corrode copper supports. The authors share methodologies and techniques used to characterize and assess the suitability of the new formulation in terms of its physical and optical properties, and to assess its stability to fluctuating relative humidity and temperature, particularly high temperatures. The new formulation was evaluated for its workability, opacity, and flexibility and for its compatibility with a selection of varnish coatings and inpainting media. Results showed that 1.5 parts of Cosmoloid H80 to 1 part of Regalrez 1126 (by weight), mixed with pigments and/or fillers, is a viable alternative to other infilling and inpainting media. It has good optical and working properties, a suitable degree of hardness, and remains stable during fluctuations in relative humidity and temperature, as well as to temperatures as high as 70°C.publishersversionepub_ahead_of_prin

Portuguese medieval polychrome sculpture in the European context: what is (un)known regarding the materials and techniques of its polychromy

A policromia é um elemento indissociável da escultura medieval, sem o qual não é possível entendê-la na sua plenitude. A degradação e a perda dos materiais, assim como as frequentes repolicromias que ocorrem ao longo do tempo, impedem muitas vezes a leitura e compreensão destas superfícies. Os estudos materiais e técnicos fornecem informação fundamental sobre a aparência e propósito originais destas obras de arte. Contudo, o conhecimento acerca da policromia portuguesa é escasso, enquanto na Europa têm vindo a ser mais sistematicamente estudadas. O presente artigo consiste numa revisão da literatura sobre materiais e técnicas utilizados na policromia original da escultura medieval, e tem como principal objetivo contextualizar as policromias portuguesas no seio das práticas Europeias. Apesar das dificuldades encontradas no tratamento de dados de estudos frequentemente muito díspares, esta revisão permitiu observar e identificar tendências, padrões, mas também particularidades geográficas, bem como cronológicas. Acima de tudo, esta revisão sublinhou o pouco que é conhecido relativamente à policromia medieval portuguesa, reforçando a urgência do seu estudo sistemático.The polychromy is an inseparable part of medieval polychrome sculptures, without which it cannot be fully understood. The degradation and loss of materials, as well as the frequent renovations of the polychromy over time result in a difficult reading and understanding of these surfaces. Material and technical studies provide a fundamental insight into the original appearance and intention of the artworks. However, the knowledge on Portuguese polychromy is scant, while in Europe it has been more systematically studied. This paper is a literature review on the materials and techniques of the polychromy of medieval sculptures, aiming to contextualize Portuguese polychromies within the European practices. Despite the difficulties in undertaking such comparisons among dissimilar studies, this review enabled to observe and identify geographical and chronological trends, patterns, and singularities. Above all, this review underlined that little is known regarding the polychromy of Portuguese medieval sculpture and reinforced the urgency of its systematic study

Painting on copper: The preparatory layer

Dans cette étude sur la technique de la peinture sur cuivre, 18 sources historiques, dans six langues différentes, datant du 17e et 18e siècle ont été rassemblées, permettant de systématiser la plupart des informations sur des matériaux utilisés et des techniques de mise en œuvre sur ce type de peintures. Douze peintures de la période mentionnée ci-dessus ont été étudiées et comparées avec la littérature historique.In this research about painting on copper technology, 18 historical sources, covering six different languages, dated from the 17th and 18th centuries were collected, allowing to systematise most information about materials and techniques applied on these sorts of paintings. Twelve paintings from the same period mentioned above were studied and compared with the historical literature

Painting on copper: research on the materials and techniques used on ground layer according to historical treatises and analytical study of two paintings attributed to the Portuguese and Flemish schools

Paintings on copper were mostly produced from the 16th century until the end of the 17th century. Nevertheless, its production never ceased completely, and examples can be found in the 20th century. This study encompassed two complementary sources of information: historical documentary research, on sources from the 17th and18th centuries; and analytical research, which involved the characterization of two paintings. The characterization included optical microscopy, for the study of the pictorial technique; micro-Raman spectroscopy, for the identification of pigments and fillers present in the preparatory layer; and stereomicroscopy, digital radiography and Particle induced X-ray emission, for the study of the support. The literature research revealed the existence of, at least, 20 documentary sources with information related to technique and materials used to paint on copper support. The analytical results confirmed the information collected from the historical literature. As pinturas sobre cobre foram produzidas, essencialmente, ao longo dos séculos XVI e XVII, mas a sua produção nunca cessou por completo, podendo encontrar-se pinturas sobre este tipo de suporte até ao século XX. Neste trabalho procedeu-se ao estudo deste tipo de pinturas segundo duas perspectivas. Por um lado, fez-se o levantamento das fontes documentais com interesse histórico e a sistematização da informação extraída da literatura dos séculos XVII e XVIII. Por outro lado, fez-se o estudo material de duas pinturas que envolveu a caracterização da técnica pictórica por microscopia óptica, a identificação de pigmentos e cargas presentes na camada preparatória por micro-espectroscopia de Raman e o estudo do suporte por estereomicroscopia, radiografia digital e espectrometria de emissão de raios X induzida por partículas (PIXE). Segundo os resultados obtidos, os materiais e as técnicas utilizadas nas duas obras são coerentes com a informação colhida nas 20 fontes literárias estudadas

Radiocarbon dating of lead white: novel application in the study of polychrome sculpture

Recently, radiocarbon dating underwent considerable technological advances allowing unprecedented sample size downscaling. These achievements introduced novel opportunities in dating cultural heritage objects. Within this pioneering research, the possibility of a direct 14C dating of lead white pigment and organic binder in paint samples was investigated on polychrome sculptures, a foremost artistic expression in human history. The polychromy, an indivisible part of polychrome sculpture, holds a key role in the interpretation and understanding of these artworks. Unlike in other painted artworks, the study of polychromies is repeatedly hampered by repaints and degradation. The omnipresence of lead white within the original polychromy was thus pursued as dating proxy. Thermal decomposition allowed bypassing geologic carbonate interferences caused by the object’s support material, while an added solvent extraction successfully removed conservation products. This radiocarbon dating survey of the polychromy from 16 Portuguese medieval limestone sculptures confrmed that some were produced within the proposed chronologies while others were revised. Within this multidisciplinary study, the potential of radiocarbon dating as a complementary source of information about these complex paint systems guiding their interpretation is demonstrated. The challenges of this innovative approach are highlighted and improvements on sampling and sample preparation are discussed

Microclimate frame for paintings on canvas exposed to extreme fluctuations in relative humidity

As autoras agradecem ao Ecomuseu Municipal do Seixal a oportunidade de realizar este estudo, nomeadamente à Dr.ª Ana Duarte e a José Meias pela grande disponibilidade e ajuda ao longo de todo o projecto. As autoras agradecem também a Stefan Michalski por ter apresentado o conceito de Garry Thomson de utilizar sílica-gel como um sistema passivo de redução das flutuações diárias e anuais de HR, no início de 1980, durante discussões com uma das autoras, a propósito do design de uma moldura microclimática para uma pintura sobre tela [28]. Este artigo foi escrito com o apoio das bolsas de doutoramento ref.ª PD/BD/135054/2017 (Sara Sá) e ref.ª PD/BD/135058/2017 (Raquel Marques) da Fundação para a Ciência e Tecnologia (FCT-MEC) e com o apoio do Laboratório Associado para a Química Verde – Tecnologias e Processos Limpos (LAQV) financiado por fundos nacionais através da FCT/MCTES (UID/ QUI/50006/2013) e co-financiado pelo FEDER, no âmbito do Acordo de Parceria PT2020 (POCI-01-0145-FEDER-007265).Ecomuseu Municipal do Seixal is aiming to exhibit three oil portraits on canvas from the 19th century in the Tide Mill of Corroios. Due to its location, intrinsic to its function of Tide Mill, the building exhibits environmental conditions characterized by severe fluctuations in temperature and relative humidity. This work aims to propose a model of microclimate frame that offers a solution for the continued preservation of the three paintings. The frame’s design was chosen based on the study of the environmental conditions (temperature and relative humidity) of the exhibition room at the Tide Mill as well as in the results of an in situ experiment involving model frames. The proposal here described, a microclimate frame with silica gel as buffering material, considered the designs presented in the literature, the individual needs of the paintings and, finally, the available budget.publishersversionpublishe