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4 results on '"Miguel, Catarina"'

1. Behind the light – specificities of the materialities of a sixteenth century illuminated antiphonary housed in the Biblioteca Pública de Évora

Author

Miguel, Catarina, Jacobs, Whitney, Ferreira, Teresa, Dias, Cristina Barrocas, and Conde, Antónia Fialho

Subjects
FORS, manuscript, iluminuras, quotidiano, manuscrito, Humanities, Multidisciplinary, antiphonary, Social Sciences, Interdisciplinary, h-EDXRF, identidades, SEM-EDS, m-FTIR, antifonário, GTG, olhares, fronteiras, μ-FTIR, illuminations, SOC000000, douramento, espaços, gilding
Abstract

This work focuses on the material characterization of a sixteenth century illuminated antiphonary housed in the Biblioteca Pública de Évora (BPE) – the Manizola 116c. Based on several optical and spectroscopic techniques, namely optical microscopy (OM), scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDS), micro-Fourier transform infrared spectroscopy (μ-FTIR), Fibre­Optic Reflectance Spectroscopy (FORS) in the ultraviolet and visible range (UV-Vis) and handheld-energy dispersive X-ray fluorescence (h-EDXRF), it was possible to identify the use of different azurite ground on different degrees of fineness to produce a range of blue hues throughout the manuscript as well as some differences in some of the paints’ compositions suggesting the presence of two different hands for producing the illuminations. Digital images of the illuminations acquired with different angles for the light source revealed very interesting features concerning the painting technique used to produce these illuminations and with what could have been the intention of the illuminator to influence the relation between the reader and the manuscript. Este trabalho baseia-se na caracterização de algumas das especificidades materiais presentes num antifonário iluminado do século XVI à guarda da Biblioteca Pública de Évora (BPE) – o Códice Manizola 116c. Da análise com recurso a várias técnicas de microscopia e espectroscopia, nomeadamente a microscopia óptica (OM), microscopia eletrónica de varrimento com um sistema de microanálise por espectroscopia de raios-X por dispersão de energias acoplado (SEM-EDS), micro-espectroscopia de infravermelhos com transformada de Fourier (μ-FTIR), espectroscopia de reflectância (FORS) no ultravioleta-visível (UV-Vis) e fluorescência de raios-X por dispersão de energia portátil (h-EDXRF), foi possível identificar a utilização de diferentes granulometrias de azurite para produzir diferentes tons de azul ao longo do manuscrito, assim como diferenças nas composições de algumas tintas, sugerindo a presença de duas mãos diferentes para a produção das iluminuras. A aquisição de imagens digitais com diferentes ângulos de iluminação revelou características muito interessantes no que diz respeito à técnica de pintura utilizada para produzir as iluminuras e com o que poderia ter sido a intenção do iluminador de influenciar a relação entre o leitor e o manuscrito.

Published
2020

3. On the use of in-situ spectroscopic techniques for the study of the provenance of historic ivories.

Author

Parungao, Dorothy, Candeias, António, Lopes, João A., and Miguel, Catarina

Subjects
*ASIATIC elephant, *AFRICAN elephant, *PRINCIPAL components analysis, *IVORY industry, *FIBER optics
Abstract

• A nondestructive and practical approach using vibrational spectroscopy and chemometrics was developed to determine ivory provenance. • Geochemical conditions, elephant physiology, and diet alter ivory composition. • Collagen, water, and hydroxyapatite content in ivory drives this classification. • Ivory from African elephants had desirable mechanical properties making it a preferred carving material. • Knowledge of ivory provenance establishes artistic context and facilitates prevention of illegal ivory trade. Ivory trafficking is a multifaceted problem that has long endangered the fate of African and Asian elephants. In field investigations, it is essential to conduct ivory inspections in a nondestructive manner to prevent the inclusion of noncompliant materials. In this research, a practical approach to identify Asian and African elephants' ivories was developed using an integrated methodology of art history, vibrational spectroscopy, and chemometrics. Spectra were acquired by an FT-IR spectrometer and a fiber optics reflectance spectrometer (FORS) in the Vis-NIR region. The discriminant methods were calibrated with spectra acquired from Asian and African elephant ivory tusks and applied to historic ivory objects (n = 78) of uncertain origin. Models based on the chemometric methods Principal Component Analysis (PCA) and Partial Least Squares -Discriminant Analysis (PLS-DA) were able to successfully classify ivory objects into Asian and African ivory, with an estimated true prediction rate (TPR) of 99 % both for African and Asian ivory samples. This study demonstrated the potential of FT-IR spectroscopy and FORS with chemometric methods as suitable tools for ivory investigations, aiding to the existing set of ivory trafficking prevention methods. [Display omitted] [ABSTRACT FROM AUTHOR]

Published
2024
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