José Carlos Frade

Spectroscopic characterization of a masterpiece: The Manueline foral charter of Sintra

The foral charter attributed by D. Manuel I of Portugal, in 1514, to the village of Sintra was studied using Energy Dispersive X-ray Fluorescence spectrometry, Raman and Infrared micro-spectroscopies. A complete characterization of the pictorial materials used in the production of this masterpiece allowed the identification of iron gall inks used in the written text; pigments such as malachite, azurite, lead white, cinnabar, yellow ochre, gold, silver and carbon black in the illuminations and letterings; filler and binder used in the production of coloring materials and inks. Gum and calcium carbonate were the most recurrent binder and filler identified in this study. Silvering and gilding were mostly obtained by applying ground silver and gold on parchment.

Applying pyrolysis-gas chromatography/mass spectrometry to the identification of oriental lacquers: study of two lacquered shields

AbstractOriental lacquers have been used as coating materials for thousands of years for wooden, ceramics, leather and metal objects. Lacquers are natural polymers obtained from three species growing in different regions of Asia: Rhus vernicifera (China, Japan and Korea); Rhus succedanea (Vietnam and Taiwan); and Melanorrhoea usitate (Myanmar and Thailand). The identification of lacquer films is important for conservation and restoration purposes, as well as for art history studies because it may help in determining the origin of the lacquered objects. In this work, pyrolysis-gas chromatography/mass spectrometry using a filament-type pyrolyser was successfully applied to the characterization of oriental lacquers. A method to identify the three kinds of lacquer was developed and applied to the study of two lacquered shields imported from Asia in the sixteenth century. The materials that constitute the shields were also examined by Fourier-transform infrared microspectroscopy and details of the lacquering technique are reported. FigureTwo lacquered shields of unknown origin imported from Asia in the 16th century

New development on materials and techniques used in the heraldic designs of illuminated Manueline foral charters by multi-analytical methods.

In the illuminated foral charters commissioned by D. Manuel I, King of Portugal (1495-1521), heraldry played a prominent role. In this work, royal emblems corresponding to the third heraldic design, applied to the Charter of Couto de Teixedo, are studied by means of EDXRF, SEM-EDS, micro-Raman, micro-FTIR and HPLC-DAD to characterize the materials and techniques used to produce this masterpiece of Portuguese Renaissance. By comparing this data with the results previously obtained in other three charters, this research allows for the first time an accurate insight into the reformed manuscripts production, especially since the illuminated charters under consideration were all investigated on the basis of similar micro-spectroscopic techniques. Inks, metal coatings, pigments, organic dyes, fillers or extenders, and binding media are discussed, and their use enlightened by the politic and legal messages the foral charters had to convey. Parchment analysis allowed us to identify the animal species, and all undertaken processes along its preparation. HPLC-DAD allowed us to differentiate the gums used. CaSO4 was observed in the parchment as a degradation product of CaCO3 used in parchment production in the presence of metal sulfates coming from the ink. Pigments used in the different colors as well as some specific phases for some colors were identified. Silvering and gilding processes, metal caratage and silver oxidation compounds were also objects of the present study.

Multianalytical approach for the authenticity of an eighteenth-century Pascal Taskin harpsichord

This paper surveys a detailed characterization of a prestigious harpsichord brought into fashion in 1782 by Pascal Taskin. The implemented analytical methodology required the use of in situ Energy Dispersive X-Ray Fluorescence (EDXRF) for elemental analysis of the color palette, optical and SEM imaging (SE and BSE modes) for the layered structure identification, Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDS) for elemental composition of the inorganic compounds, Fourier Transform Infrared (FTIR) spectroscopy for some binders and THM-GC/MS as well for resinous layers identification. By cross-checking these data with those obtained by digital radiography, it was concluded that a true ravalement of the harpsichord was in fact undertaken and that, among more than five interventions applied to the instrument until the present day, the third one may correspond to the one performed at Pascal Taskins time.

Microscopy and X-Ray Spectroscopy Analyses for Assessment of Gilding and Silvering Techniques of Portuguese Illuminated Manuscripts

The objects of this study are various local charters (cartas de foral, in Portuguese) granted by Dom Manuel I, King of Portugal (1495-1521), which substituted for medieval ones and were intended to achieve an administrative unification. These are luxuriously illuminated manuscripts, and our study aims at obtaining a better understanding of the gilding and silvering techniques applied to the parchments, in which the forais were written, between 1500 and 1520. The combined use of microscopy and X-ray spectroscopy analyses allowed us to identify the vestigial materials used for making the parchments, including products such as salt (NaCl), lime (CaO), pumice stone (SiO2+Al2O3), and chalk (CaCO3). Chalk was employed as a whitening agent to give the parchment its final color and opacity. Shell-gold and shell-silver mixed in with animal glue or gum binding media were directly applied on type 1 and 3 forais, while very thin gold leaves (<1 µm) were applied over lead-based tempera grounds (50-180 µm thick) in type 2 forais. Silver was always employed in its finest form without a further protective layer (thus its recursive state of corrosion), while gold was used in various alloy grades.

Análise comparativa das técnicas e materiais em pinturas de caixotões no norte de Portugal

As origens dos tectos em caixotoes remontam a Antiguidade Classica. Mais tarde, utilizaram‑seno Renascimento Italiano, mas foi no panorama portugues que atingiram uma especialsingularidade artistica.A presente investigacao pretende colmatar a carencia de estudos no que respeita as tipologias,as formas, as tematicas, as tecnicas e aos materiais utilizados neste genero artisticono Norte de Portugal.A construcao de uma base de dados para cinco distritos e a posterior quantificacao dosresultados foram metodologias imprescindiveis para a classificacao das pinturas em caixotoes.Atraves da realizacao de exames e analises foi feita uma comparacao a nivel tecnico ematerial de dois casos da mesma autoria em que se verificaram diferencas sobretudo nacamada de preparacao.