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For the first time, IR reflectography was used for analysing the production technique of incunabula, unveiling impressive results concerning the identification of underprintings and the relation with its coloured illuminated representations. In this work, the procedures followed for producing a late-fifteenth-early-sixteenth century incunabulum produced in the Parisian workshop of Germain Hardouyn held by the Biblioteca Pública de Évora (Inc.438) were characterized by IR reflectography. Unexpected features concerning the creative process of the hand-coloured procedures were achieved, reflecting an illuminator strongly influenced by the devotions that were in fashion at the time, unlike the engraving plates used on the incunabulum, whose representations faithfully followed the references of the Holy Scriptures. For the evaluation of the originality of the painted surfaces, a representative painted illustration — the Adoration of the Magi , f. 11 — was full characterized using a microscopic and spectroscopic approach (OM, SEM-EDS, Raman microscopy, μ-FTIR). Three representative coloured-paints (white, blue and gilding) of the painted illustrations from the Adoration of the Magi (f. 11), the Pietà (f. 47v) and the Pentecost (f. 65v) were characterized and compared to infer on the contemporaneity of these painted illustrations. [ABSTRACT FROM AUTHOR]

Abstract: Vermilion red, mercury sulphide (α-HgS), was one of the most important reds in art and its use as a pigment dates back to Antiquity. In medieval Europe, it could be mined as cinnabar, or produced as vermilion by heating mercury with sulphur. This work aims to study the production of synthetic vermilion as a medieval pigment and to confirm which was the source (mineral or artificial) of the reds used in Portuguese medieval illuminations. The production of synthetic vermilion was based on the process described in the Judaeo-Portuguese medieval treatise “The book on how to make colours”, using materials and technologies as close as possible to the medieval ones. The reaction mechanism was studied by following the heating process by X-ray diffraction, and it was possible to conclude that the transformation from black cubic β-HgS into red hexagonal α-HgS is a solid-state phase transition, occurring at 235 °C. This result is contrary to what published in technical art literature, in which this process is described as a sublimation. Moreover, Scanning Electron Microscopy evidenced a sinterization effect on the artificial vermilion, not found in medieval original samples nor in paints prepared with mineral cinnabar from Almadén (Spain). Red mercury sulphide, natural and synthetic, was then prepared as a parchment-glue paint and compared to proteinaceous red paints from 12th–13th century miniatures produced in important medieval monasteries, previously fully characterized by a multi-analytical approach (μ-Energy dispersive X-ray fluorescence, μ-Fourier Transform Infrared Spectroscopy, Raman microscopy). A comparative Electron probe microanalysis of the red paints point to a mineral provenance for medieval vermilion found in Portuguese illuminations. [Copyright &y& Elsevier]

• 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]