Estudo do efeito da adição de iões metálicos na corrosão de vidros potássicos

Dissertação apresentada para obtenção do Grau de Doutor em Conservação e Restauro, especialidade em Ciências da Conservação, pela Universidade Nova de Lisboa, Faculdade de Ciências e TecnologiaFragmentos de vitrais do séc. XV, provenientes do Mosteiro de Santa Maria da Vitória (Batalha), foram analisados pela primeira vez, de forma sistemática, de forma a obter-se um termo de referência para o estudo da corrosão de vidros potássicos antigos. Pare este estudo recorreu-se às espectroscopias de feixes de iões e de infravermelhos, tendo-se determinado que os vidros de base são formados por misturas de óxidos de Si, K, Ca, e de óxidos de Mn, Fe e Cu, usados como corantes, em composições que estão de acordo com o receituário da época. As grisalhas revelaram-se misturas de óxidos de Si e Pb, com elevadas concentrações de Fe e Cu, e também de Zn, cuja presença é notável uma vez que não se encontra habitualmente associado com aqueles metais. A camada de corrosão mostrou-se formada por carbonatos e oxalatos de Ca. Estabelecida a composição de referência, pretendeu-se estudar neste trabalho o efeito da introdução de elementos de coloração na deterioração de vidro potássico em presença de água, para compreender os mecanismos de corrosão dos vitrais medievais,essencial a um trabalho de conservação adequado. Assim, produziram-se vidros modelo com composições SiO2−CaO−K2O semelhantes às encontradas nos vitrais do Mosteiro da Batalha, a que foram adicionados óxidos de Cu, Fe ou Mn, isoladamente ou em combinação. Estes vidros foram sujeitos a ensaios de imersão em água de forma a simular ambientes de elevada humidade. A corrosão e a sua progressão foram caracterizadas por técnicas espectroscópicas de feixes de iões e de infravermelhos com transformada de Fourier, e por microscopia óptica, em combinação com a avaliação das alterações da solução aquosa, em particular o seu pH. As condições de testes exploradas, com e sem agitação do meio, conduziram a diferentes morfologias de superfície associadas com as diferentes taxas da corrosão. Mostra-se que se formam camadas superficiais de carbonato de Ca, e uma camada rica em Si nos períodos mais longos da imersão. Para além destas, encontram-se camadas enriquecidas nos elementos da transição, e uma corrosão inicial mais rápida nos vidros dopados com Cu. Este trabalho mostra que as condições experimentais escolhidas reproduzem bem a forma de corrosão encontrada nos vidros antigos de composição similar e sujeitos às condições atmosféricas ao longo de cinco séculos, e que o pH pode ser um bom parâmetro para estudar as cinéticas da corrosão em condições de humidade elevada

A new and simple optical sensor for the detection of formic acid unleashed by wooden storage or display materials used in museums and responsible for accelerating glass deterioration

Organic pollutants such as formic acid , acetic acid and formaldehyde released by some materials (mainly wood) used for storage and display can play an important role on the alteration of the glass structure due to the alkali leaching process. It as been determined that formic acid when present inside storage or display cabinets is the one that affects most glass integrity , accelerating and deepening the alkali leaching from the silica matrix. As this situation can affect many museums on their glass collections , monitoring this compound would be of great importance for indoor preservation purposes. An optical sensor based on the layer-­‐by-­‐layer (LbL) electrostatic self-­‐assembly process is under development to identify indoor formic acid based on the immobilization of chemo-­‐responsive dyes in polymeric structures. The sensors are based on an optical response resulting from the reaction between immobilized dyes and the referred organic pollutant .publishersversionpublishe

A closer look at radiation, colour and museum lighting topics

Funding Information: Research funding: This work was supported by National Funds through FCT-Portuguese Foundation for Science and Technology under the Projects (UIDB/50006/2020 and UIDP/50006/2020 – LAQV; and UIDB/00729/2020 and UIDP/00729/2020 – VICARTE). Publisher Copyright: © 2023 the author(s), published by De Gruyter, Berlin/Boston 2023.Introduction to Conservation Science (ICS) is a curricular unit (CU) from the bachelor's degree in Conservation-Restoration at NOVA School of Science and Technology. This CU was created in 2017 to fill a gap in the academic degree - the need for a bridge between fundamental sciences (1st year) and conservation-restoration diagnosis (3rd year). For this reason, ICS was designed with the main goal of teaching 2nd year students how to look at, approach and solve problems of Cultural Heritage, through the combination of reflexive thinking and object-led analysis. ICS was first designed by an expert in Conservation Science with academic background in physics. However, from the perception of the students' struggle to understand the purpose of ICS subjects to their future professional activity, a professor with expertise in Conservation and Restoration was invited in 2019 to work together in the re-design of the CU, through an integrated approach between the two experts. ICS was then revised with the introduction of new perspectives and topics, as well as new communication routes to students. This work highlights this partnership as a good practice methodology to involve conservation-restoration students into science, focusing on the ICS classes specifically dedicated to radiation, colour, and museum lighting.publishersversionpublishe

Defining the first preventive conservation guidelines for hand-painted magic lantern glass slides

The authors acknowledge the support of the Portuguese Foundation for Science and Technology (FCT-MCTES), through the doctoral program CORES-PD/00253/2012, for the PhD grant PD/BD/136694/2018 (Ângela Santos), and Research Unit VICARTE (UIDB/00729/2020). This research has benefited from the use of the infrastructure PRISC (Portuguese Research Infrastructure of Scientific Collections). The authors are also grateful to all the institutions and individuals that accepted to participate in the online survey, and to the Portuguese Cinematheque – Museum of Cinema, and National Museum of Natural History and Science of the University of Lisbon for the collaboration with the project "Lanterna Magica – Technology and Preservation of Painted Glass Slides for Projection with Magic Lanterns". The authors would also like to acknowledge for the relevant comments of the reviewers that significantly contributed to the improvement of the manuscript.This article intends to define and make available guidelines for the preventive conservation of hand-painted glass slides for magic lanterns, the first optical instruments for the projection of images, invented in the 17th century. For this purpose, around 300 hand-painted glass slides from the Portuguese Cinematheque - Museum of Cinema (CP) and Nacional Museum of Natural History and Science of the University of Lisbon (MUHNAC), were studied in terms of representativity in these collections, discursive genre, type of construction or movement mechanism, state of preservation and degradation problems. A survey was designed and distributed to institutions across the globe aiming for an overview of the formal characteristics of the collections of magic lantern slides and the preventive and interventive conservation measures undertaken. The guidelines are focused on the environmental conditions (temperature, relative humidity, and light), fine particles and pest control, storage and display conditions and materials, as well as handling. Recommendations on performative projections or demonstrations are also provided.publishersversionpublishe

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

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

The Influence of Raw Materials on the Stability of Grisaille Paint Layers

This research was funded by Fundação para a Ciência e Tecnologia de Portugal (project UIDB/50025/2020-2023, researcher grant CEECIND/02249/2021. Publisher Copyright: © 2022 by the authors.Grisaille is a glass-based paint made by mixing metal oxides (iron or copper) with ground lead-silica glass. The different materials used in the grisailles production (coloring agents, base glasses, or vehicles) can significantly impact their long-term stability along with the firing conditions. The main objective of this study was to achieve a better understanding of how raw materials influence the production and stability of these paints. To achieve this goal, 27 grisailles were produced, changing the raw materials, proportions, and firing conditions. The produced grisailles were characterized by X-ray fluorescence and diffraction, colorimetry, roughness measurement, and contact angle analysis. Adhesion and cleaning tests were also made. The use of different coloring agents has a significant impact on the final appearance and on the chemical and mechanical stability of the grisailles, but the latest is more affected by both firing temperature and the proportion between pigments and base glasses.publishersversionpublishe

A First Approach to the Study of Winsor & Newton’s 19th-Century Manufacture of Madder Red Lake Pigments

Funding Information: We are grateful to Winsor & Newton, ColArt Fine Art & Graphics Ltd., for allowing the creation of the archive project. The W&N 19th Century Archive Database, designed by Mark Clarke and Leslie Carlyle, was funded by the Netherlands Institute for Scientific Research (NWO) as part of the De Mayerne Programme and, in the UK, by a Resource Enhancement Grant from the Arts and Humanities Research Council (AHRC). We thank Marta F. Campos for purchasing the Rose Madder 19th-century oil paint tube on eBay and dating it. We also appreciate the comments of the participants at the Dyes in History and Archaeology 41. Funding Information: This work was funded by the Portuguese Foundation for Science and Technology (FCT) of the Ministry of Science, Technology and Higher Education (MCTES) through the Research Units VICARTE (UIDB/00729/2020; UIDP/00729/2020) and LAQV-REQUIMTE (UIDB/50006/2020; UIDP/50006/2020), project MAGICA (PTDC/ART-PER/1702/2021), project REDiscover (2022.02909.PTDC), Vanessa Otero’s 2020.00647.CEECIND and Paula Nabais’s 2021.01344.CEECIND. Publisher Copyright: © 2023 by the authors.This paper focuses on the first investigation of the 19th-century manufacture of red lake pigments obtained from madder by Winsor & Newton (W&N), prominent artists’ colourman at that time. The first approach to their manufacture was carried out by studying the madder entries of the company’s book P1, found in the W&N 19th Century Archive Database. Eleven production records were discovered under names such as Rose Madder, Madder Carmine, Madder Lake and Madder Rose. Three main methods of synthesis were identified and reproduced, revealing three main steps: washing of the madder roots (Rubia tinctorum L.); extraction in acid media and complexation with Al3+ using alum; and precipitation by the addition of salts such as ammonium carbonate and sodium borate. The syntheses were followed by UV-VIS spectroscopy, and the pigments were further characterised by colourimetry, Energy-Dispersive X-Ray Fluorescence Spectrometry (XRF), Fourier Transform Infrared Spectroscopy (FTIR) and High-Performance Liquid Chromatography-Diode Array Detector (HPLC-DAD). They all exhibited a rose hue in a highly insoluble aluminate matrix. Although the dye extraction was incomplete, alizarin, purpurin and pseudopurpurin were identified. An analytical comparison with a Rose Madder 19th-century oil paint tube was also performed by micro-FTIR and microspectrofluorimetry. This work intends to be foundational to a systematic study of the W&N’s 19th-century madder colours aiming to contribute new knowledge towards their identification and preservation in heritage objects.publishersversionpublishe

Nanotechnology in Roman Opaque Red Glass from the 2nd Century AD. Archaeometric Investigation in Red Sectilia from the Decoration of the Lucius Verus Villa in Rome

PD/BD/135053/2017 UID/EAT/00729/2019This work aims to characterise the chemical composition of Roman opaque red glass sectilia dated to the 2nd century A.D and to shed light on Roman glassmaking production of different shades of red, from red to reddish-brown. Due to the lack of technical historical sources for this period many questions about technological aspects still remain. In this project a multi-disciplinary approach is in progress to investigate the red glass sectilia with several red hues from the Imperial Villa of Lucius Verus (161–169 A.D.) in Rome. First, colorimetric measurements were taken to identify the various red hues. The second step was chemical characterization of the samples and the identification of crystalline colouring phases. Particle Induced X-Ray Emission (PIXE) analysis was used to investigate the chemical composition of these glass samples, while the crystalline phases were identified by Raman Spectroscopy and Scanning Electrons Microscope with Energy Dispersive X-ray Spectrometry (SEM-EDS). Using SEM-EDS nanoparticles were detected as a colouring agent, the chemical composition and the morphology of which has been studied in depth. This information has been compared with the colorimetric analysis to establish any correlation with the different colour hues.publishersversionpublishe

Glass in Cultural Heritage – An Introduction

Proceedings of the Chemistry and Conservation ScienceA brief description of different types of silicate glasses is made and the origin of colour in glasses is discussed. The principles of corrosion in glass, illustrated with a few examples, will be explained. Applications of several techniques in the chemical characterization of glasses will be shown, namely X-ray Fluorescence Spectrometry (XRF), Scanning Electron Microscopy (SEM), Optical Absorption Spectroscopy and Laser Ablation Fourier Transform Ion Cyclotron Resonance Mass Spectrometry (LA-FTICR/MS), and Particle Induced X-ray Emission (PIXE)

An Overview of Germanic Grisailles through the Stained-Glass Collection at Pena Palace

The authors would like to thank António Nunes Pereira (Director) and all the team at Pena National Palace for in their efforts to make this and similar ongoing research possible through their collaboration and stimulus, as well as to Parques de Sintra—Monte da Lua for access to the collection studied. The authors also thank the anonymous reviewers for their valuable contribution to the improvement and enrichment of the manuscript. Publisher Copyright: © 2022 by the authors. Licensee MDPI, Basel, Switzerland.The lack of studies reporting the characterisation of Germanic grisaille is evident, despite the recent interest of researchers in this glass painting material. This work consists of the first assessment of Germanic grisaille’ chemical composition on a wide chronology (14th–19th centuries), that was only possible through the unique stained-glass collection of King Ferdinand II of Portugal. From the considerable amount of panels produced in Germanic territory and assembled by Ferdinand, twenty-two panels were characterised, and some trends of glass support typical composition and grisaille recipes were verified through this case study. A copper-based grisaille appears to have been the preference up to the 18th century. The 19th century shows higher diversity in composition, with new compounds (such as Co, Cr, Mn) appearing as colourising materials. However, with a limited number of analyses, and dispersed throughout time and different geographic locations, the results of this study are unprecedented, by being able to present the first overview on grisaille composition in Germanic stained glasses.publishersversionpublishe