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Projeto de investigação
Glass and Ceramic for the Arts
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Publicações
Amarillo de Nápoles
Publication . Veronesi, Umberto; Bandiera, Mario; Manso, Marta; Ruivo, Andreia; Vilarigues, Márcia; Coentro, Susana; VICARTE - Vidro e Cerâmica para as Artes; LIBPhys-UNL; DCR - Departamento de Conservação e Restauro; Sociedad Espa?ola de Ceramica Y Vidrio
Naples yellow was widely used across different types of artwork. Technical studies identified a binary Pb–Sb type as well as modified ternary variants with either zinc or tin in the structure. Although these variants were the object of previous experimental studies, a better understanding of the impact of the glazing procedure on the chromatic, chemical and crystallographic characteristics of the pigment is still lacking. In this work, several historical Naples yellow recipes were re-worked and subsequently applied and fired on test tiles, over a white glaze. The results show that the interaction between pigment and glaze produces important modifications to the colour, chemistry and structure of the pigment. Such modifications will strongly impact the reconstruction of historical recipes, with major consequences for identifying Naples yellow variants on artwork and investigating artistic practices.
Lanterna Magica - Technology and Preservation of Painted Glass Slides for Projection with Magic Lanterns
Publication . Santos, Ângela Barros; Vilarigues, Márcia; Otero, Vanessa
Magic lantern is the term, deriving from the Latin
lanterna magica, used to designate an early
form of a slide projector in which transparent positive images depicted on glass slides (magic
lantern slides) were projected onto a white surface such as a wall or screen. The invention of this
apparatus in the mid-17th century allowed, for the first time, the projection of illuminated and
magnified images to be viewed by collective audiences.
The materials and methods applied to produce painted magic lantern glass slides and specific
conservation strategies remain an understudied field. As a result, their severe deterioration
problems represent an aggravated challenge for conservation professionals. The present work
was developed as the first systematic study on the materials and techniques used to produce
painted magic lantern glass slides (entirely painted and coloured over printed outlines), bridging
the gap between 18th- and 19th-century written and material sources while addressing preventive
conservation and restoration challenges.
A literature review of 18th- and 19th-century written sources stating the materials and
techniques applied in the magic lantern slide production was conducted, allowing for an
overview of the types of glass support procured and the colour palette and binders available.
The evolution of magic lantern instruments and illumination systems is also explored.
Formulations of Winsor & Newton watercolours were investigated, revealing great complexity
and individuality depending on the colourant used in each formulation.
The context of the use and impact of the magic lanterns in Portugal throughout time was
briefly investigated, and two Portuguese collections of magic lantern slides held by the
Portuguese Cinematheque – Museum of Cinema (CPMC) and the National Museum of Natural
History and Science (MUHNAC) of the University of Lisbon were selected for the present study.
These collections’ characteristics are discussed, and the glass support and painting materials
used in 48 of their slides, attributed to a European production of the 18th and 19th centuries, were
studied by resorting to a multi-analytical approach.
The techniques of Energy Dispersive X-Ray Fluorescence spectrometry (EDXRF), Ultraviolet-
Visible (UV-VIS) and Raman spectroscopies were applied
in situ, and Fourier Transformed
Infrared spectroscopy (FTIR) and Surface-enhanced Raman Spectroscopy (SERS) were carried
out on micro-samples. EDXRF allied with semi-quantitative analysis by WinAxil program
(making use of glass standards from Corning Museum of Glass (Corning, NY, USA) for
validation) allowed the identification of four main glass compositional groups: potassium-rich,
mixed-alkali, high-lime low-alkali, and synthetic soda-rich glass. These results, along with visual
analysis, verified the preference for high-quality glass reported by historical documentation, and the characteristics of each compositional group helped in the slides’ attributions to certain
regions and periods of production. By complementing EDXRF with UV-VIS, Raman, and FTIR
spectroscopy, it was possible to identify several colourants, including yellow ochre, gamboge,
red ochre, cochineal-based lakes, geranium lakes, vermilion, Prussian blue, ultramarine blue,
copper-green, and carbon black, and fillers such as gypsum. Regarding these paints’ binding
components, FTIR detected terpenoid resins, namely mastic and shellac and the possible
presence of oils. Finally, the SERS technique enabled the identification of carminic acid in a
reddish micro-sample. These analyses verified the use of a reduced colour palette, the artist’s
preference for bright and pure colours, and simple mixtures to create different hues and
gradients.
This material characterisation unveiled a strong correlation between the glass and painting
materials identified in 18th- and 19th-century slides and those described by coeval written sources
and enabled the development of a timeline comprising the evolution of glass procured and the
colour palette used in the production of painted slides. It was also possible to find differences
between manufacturers, countries, and periods, which may help attribute slides more precisely.
Finally, the conservation challenges faced by caretakers and conservation professionals were
addressed. The state of preservation of more than 350 slides of interest from the Portuguese
collections studied was assessed, and the most common damages were identified, some of them
resorting to Optical Microscopy. This study demonstrated that the glass and the painting layers
are the most fragile and damaged materials that compose these slides. Considering the material
knowledge gathered and inputs from national and international institutions shared through a
questionnaire, preventive conservation guidelines tailored to painted slide collections were
developed to complement current conservation standards. As around 20 % of the slides studied
are in poor or very poor conditions and need remedial or restoration actions, and no guidelines
for these procedures on painted magic lantern slides were found by the author, this study also
explored methods for cleaning painted surfaces and reassembling their glass support. However,
a deep investigation regarding consolidation materials and methods for these transparent
painting layers is fundamental.
This interdisciplinary research offers a valuable contribution to the understanding of painted
magic lantern slides, aiming at increasing awareness and appreciation for these collections to
ensure their long-term preservation and fruition by present and future generations.
CIE color coordinates for the design of luminescent glass materials
Publication . Ruivo, Andreia; Laia, César; VICARTE - Vidro e Cerâmica para as Artes; DCR - Departamento de Conservação e Restauro; LAQV@REQUIMTE; John Wiley & Sons, Inc.
New photoluminescent materials have numerous possibilities in many different areas from technological applications to contemporary glass art and design, encouraging the development of new forms and products. Glass luminescent materials, known for their exceptional durability and recyclability, position glass as an ideal solution for fostering a more sustainable future. In recent years, white luminescence in glass and ceramics has been the subject of several investigations about its possible application in white light-emitting diodes (WLED). Color coordinates and CIE chromaticity diagrams serve as valuable tools to represent and define the range of luminescent colors achievable in a particular composition. These aid in understanding wheter a composition can be used to produce white luminescence or various other colors. In this study, a soda-lime silicate glass composition was doped with a mixture of different lanthanide oxides to increase the luminescence color palette. The same glass sample can also present different colors by changing the excitation light, allowing higher tunability of luminescent colors. It was effectively demonstrated the extensive spectrum of colors produced, which was represented through luminescence color coordinates for all synthesized glasses. Moreover, the possibility of detecting if an excited state process is occurring was studied by calculating the lanthanides factors and comparing them with those used in the glass synthesis. Nevertheless, it is shown that the energy transfer process has to be significant to influence the color coordinates and the calculation of the factors.
Amber “Alchemy”
Publication . Santos, Catarina Reis; Ruivo, Andreia; Carneiro, Ana; Veiga, João Pedro; Palomar, Teresa; Coutinho, Inês; DCR - Departamento de Conservação e Restauro; VICARTE - Vidro e Cerâmica para as Artes; CIUHCT - Centro Interuniversitário de História das Ciências e da Tecnologia; CENIMAT-i3N - Centro de Investigação de Materiais (Lab. Associado I3N)
Amber glass has been produced since at least the 6th century BC. Its value derives from its ability to mimic natural amber and, later, from its ultraviolet filtering properties. Until the 19th century, amber glass was widely used for the storage of food and medicines because its protective properties had been empirically recognized. This study investigates historical methods of amber glass production by using glass recipes from four Portuguese arcana (1793–1975) and focusing on Fe-S and Fe-Mn chromophores. Five recipes were reproduced under controlled laboratory conditions, resulting in 21 experiments. Of these, only 10 produced amber glasses were with different shades. Chemical compositions were analysed by WDXRF, while DSC and dilatometry were used to assess thermal properties. Vickers hardness tests and UV–visible absorption spectroscopy provided insight into mechanical strength and chromophore presence. The study found that FeS amber glass was more difficult to produce than Fe-Mn amber glass, given the complex variables involved in the former, such as SO3 volatility affecting the final product. Reproduction of historical recipes showed that, even without modern chemical knowledge, historical glassmakers developed practical, empirical methods for making amber glass. These findings contribute to a broader understanding of glass conservation and highlight the importance of historical glass recipes for the interpretation and conservation of glass objects.
Determination of Boron Content in Surface Paintings From Historical Stained-Glass Windows
Publication . Maestro-Guijarro, Laura; Sedano, Mercedes; Schibille, Nadine; Pradell, Trinitat; Castillejo, Marta; Oujja, Mohamed; Palomar, Teresa; VICARTE - Vidro e Cerâmica para as Artes; Wiley
Stained-glass windows are often painted with grisailles and enamels. These glassy materials have a low melting temperature and are fixed to the base glass by firing processes. Lead and/or boron are commonly added to the painting material to lower their melting temperature so that they can melt without deforming the glass support. In the present study, model glass samples (with well-known boron content), replica and historical materials were analysed for their composition using Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS) and Laser Induced Breakdown Spectroscopy (LIBS). The imprint left on the analysed samples after laser irradiation was observed using optical profilometry. The feasibility of using LIBS in situ as a suitable quantitative analytical technique to detect the presence of boron in historical enamels even in very small quantities was assessed. Quantitative information on historical Spanish enamels and grisailles was obtained from calibration curves generated from the model glass samples with known boron content. The proposed procedure enables a satisfactory chemical quantitative study of historical glass materials in situ, regardless of their size, provenance, and chronology.
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Entidade financiadora
Fundação para a Ciência e a Tecnologia
Programa de financiamento
6817 - DCRRNI ID
Número da atribuição
UIDP/00729/2020