Possible Radiation-Induced Damage to the Molecular Structure of Wooden Artifacts Due to Micro-Computed Tomography, Handheld X-Ray Fluorescence, and X-Ray Photoelectron Spectroscopic Techniques

This study was undertaken to ascertain whether radiation produced by X-ray photoelectron spectroscopy (XPS), micro-computed tomography (μCT) and/or portable handheld X-ray fluorescence (XRF) equipment might damage wood artifacts during analysis. Changes at the molecular level were monitored by Fourier transform infrared (FTIR) analysis. No significant changes in FTIR spectra were observed as a result of μCT or handheld XRF analysis. No substantial changes in the collected FTIR spectra were observed when XPS analytical times on the order of minutes were used. However, XPS analysis collected over tens of hours did produce significant changes in the FTIR spectra

French Rococo Ébénisterie in the J. Paul Getty Museum

The first comprehensive catalogue of the Getty Museum’s significant collection of French Rococo ébénisterie furniture. This catalogue focuses on French ébénisterie furniture in the Rococo style dating from 1735 to 1760. These splendid objects directly reflect the tastes of the Museum’s founder, J. Paul Getty, who started collecting in this area in 1938 and continued until his death in 1976. The Museum’s collection is particularly rich in examples created by the most talented cabinet masters then active in Paris, including Bernard van Risenburgh II (after 1696–ca. 1766), Jacques Dubois (1694–1763), and Jean-François Oeben (1721–1763). Working for members of the French royal family and aristocracy, these craftsmen excelled at producing veneered and marquetried pieces of furniture (tables, cabinets, and chests of drawers) fashionable for their lavish surfaces, refined gilt-bronze mounts, and elaborate design. These objects were renowned throughout Europe at a time when Paris was considered the capital of good taste. The entry on each work comprises both a curatorial section, with description and commentary, and a conservation report, with construction diagrams. An introduction by Anne-Lise Desmas traces the collection’s acquisition history, and two technical essays by Arlen Heginbotham present methodologies and findings on the analysis of gilt-bronze mounts and lacquer

The treatment of a longcase clock attributed to Jean-Pierre Latz: alternative approaches to the removal of copper corrosion products on Boulle-style marquetry

A longcase clock attributed to Jean-Pierre Latz from the collection of the Cleveland Museum of Art was treated at the J. Paul Getty Museum in 2012. The clock is dated to 1744 and is decorated with Boulle-style marquetry and elaborate gilt-bronze mounts. As part of the treatment, the tarnished brass marquetry was to be cleaned and brought into visual balance with the mounts’ gilded surfaces. The application of a peelable protein poultice proved effective in removing copper corrosion products from the brass elements without compromising the marquetry and its engravings. Accompanying research has pointed out the vulnerability of aged turtle shell to the heat and alkalinity related to the application of the protein poultice. As a result of this, precautionary measures could be identified.L’équipe du J. Paul Getty Museum a restauré en 2012 un régulateur de parquet attribué à Jean-Pierre Latz actuellement dans la collection du Cleveland Museum of Art. Cette horloge à décor de marqueterie Boulle richement ornée de bronzes dorés est datée de 1744. Il était en particulier nécessaire de rendre leur éclat aux parties en laiton, devenues trop ternes en regard de la dorure des bronzes. L’utilisation d’un film de gel pelable appliqué sur une compresse à la colle protéique a démontré son efficacité dans l’élimination des produits de la corrosion du cuivre sur les éléments en laiton, sans altérer la marqueterie et ses gravures. Les recherches menées à cette occasion ont mis en lumière la fragilité de l’écaille de tortue ancienne en présence du milieu chaud et alcalin introduit par la compresse à la colle protéique. Des mesures de précaution ont pu être définies à cet égard

Ochre-Based Pigments in the Tablinum of the House of the Bicentenary (Herculaneum, Italy) between Decorative Technology and Natural Disasters

Ochre-based pigments have been employed since the first artistic expressions of mankind, with widespread diffusion during the Roman civilization. Such prominent use influenced their technological development, focused on functional and aesthetic optimization through complex manufacturing procedures. Furthermore, their appearance is also influenced by degradation processes, sometimes driven by natural disasters such as the eruption of Mount Vesuvius in 79 AD, in which yellow ochres of Vesuvian sites were sometimes converted to red by thermal alteration. In this contribution, a multi-analytical approach was adopted based on preliminary non-invasive investigations complemented by laboratory analyses to characterize the painted surfaces of the tablinum of the House of the Bicentenary (Herculaneum) with a particular focus on the ochre-based monochrome backgrounds. The study was aimed at (a) reconstructing the original color scheme of the walls and (b) deciphering the complex decorative techniques adopted by Roman craftsmen. The analytical results allowed testing and defining analytical procedures for the discrimination between the original and converted red pigments. Furthermore, these studies indicated that specific decorative technologies were adopted according to aesthetic, functional, and economic purposes, including the utilization of various qualities of ochre with different compositional and textural properties, and the mixture of ochre pigments with other compounds

Analysis of the CHARM Cu-alloy reference materials using excimer ns-LA-ICP-MS: Assessment of matrix effects and applicability to artefact provenancing

Excimer nano-second laser ablation inductively coupled plasma mass spectrometry (ns-LA-ICP-MS) is an important tool in chemical characterization of Cu alloys. However, variable matrix-induced elemental fractionation in Cu alloys poses a significant challenge. We systematically investigate this issue by analysing the Cultural Heritage Alloy Reference Material Set (CHARM) of Cu alloy targets. The extent to which silicate glass reference materials can be used when analysing Cu alloy targets is determined, as is the optimal internal standard, for a wide range of Cu alloy compositions. Analyses were further optimized by quantitative assessments of the use of CHARM end-member materials as external standards for other CHARM Cu alloy targets. The variable magnitude of the observed matrix effects is most readily explained by variations in Cu/Zn ratios and resulting differences in melting and boiling points, compared with external reference materials, making the Zn-rich Cu alloy targets most prone to matrix effects. With the correct choice of an external matrix-matched standard (Pb-rich CHARM reference material 32X LB14F) and internal element standardization, an accuracy of < 20% can be achieved for virtually all elements of interest in brass and bronze artefacts, which is a significant improvement compared with the use of glass external reference materials

Analysis of the CHARM Cu-alloy reference materials using excimer ns-LA-ICP-MS: Assessment of matrix effects and applicability to artefact provenancing

Excimer nano-second laser ablation inductively coupled plasma mass spectrometry (ns-LA-ICP-MS) is an important tool in chemical characterization of Cu alloys. However, variable matrix-induced elemental fractionation in Cu alloys poses a significant challenge. We systematically investigate this issue by analysing the Cultural Heritage Alloy Reference Material Set (CHARM) of Cu alloy targets. The extent to which silicate glass reference materials can be used when analysing Cu alloy targets is determined, as is the optimal internal standard, for a wide range of Cu alloy compositions. Analyses were further optimized by quantitative assessments of the use of CHARM end-member materials as external standards for other CHARM Cu alloy targets. The variable magnitude of the observed matrix effects is most readily explained by variations in Cu/Zn ratios and resulting differences in melting and boiling points, compared with external reference materials, making the Zn-rich Cu alloy targets most prone to matrix effects. With the correct choice of an external matrix-matched standard (Pb-rich CHARM reference material 32X LB14F) and internal element standardization, an accuracy of < 20% can be achieved for virtually all elements of interest in brass and bronze artefacts, which is a significant improvement compared with the use of glass external reference materials

Agate Analysis by Raman, XRF, and Hyperspectral Imaging Spectroscopy for Provenance Determination

Raman, XRF, and hyperspectral data for the analysis of quartz and moganite ratios in agates from Brazil and Germany

The Copper CHARM Set: A New Set of Certified Reference Materials for the Standardization of Quantitative X-Ray Fluorescence Analysis of Heritage Copper Alloys

International audienceThis paper introduces a new set of certified reference materials designed to aid scientists and conservators working in cultural heritage fields with quantitative X-ray fluorescence analysis of historical and prehistoric copper alloys. This set has been designated as the Copper CHARM Set (Cultural Heritage Alloy Reference Material Set). The Copper CHARM Set is designed to be used by a wide range of museum-, art- and archaeology-oriented scientists and conservators to help improve the accuracy and range of their calibrations for quantitative ED–XRF spectrometry of copper alloys, and also increase the number of elements that can routinely be quantified. In addition, the common use of a single core set of the reference materials is designed to significantly improve inter-laboratory reproducibility, allowing greater data sharing between researchers and thus furthering possibilities for collaborative study