Jana Sanyova

Orpiment and realgar, both arsenic sulfide pigments respectively used for their vivid yellow and red-orange hues, are two of many artists' pigments that appear not to be stable upon light exposure, quickly degrading to arsenic trioxide and arsenate. This often results in whitening or transparency in the painted surfaces. While conventional techniques such as microscopic Raman (μ-RS) and microscopic Fourier transform infrared (μ-FTIR) spectroscopies can allow a quick and relatively easy identification of the orpiment, realgar, artificial arsenic sulfide glass and, to some extent, arsenic oxide, the identification and visualization of distributions of the degradation products – and especially arsenate compounds – in the paint micro-samples is generally more challenging. This challenge is due to the rather unfavorable limit of detection and low spectral resolution of such conventional spectroscopic techniques. This restricts the conclusions that can be drawn regarding the conservation state of valuable works of art. In this paper, we present how synchrotron radiation (SR) based techniques can overcome this challenge while working on painting cross-sections taken from a 17th-century painting by the Flemish artist Daniël Seghers (oil on canvas, Statens Museum for Kunst, Denmark) and an 18th-century French Chinoiserie (private collection, France). SR micro-X-ray fluorescence (μ-XRF) mapping analysis performed on a visually degraded orpiment-containing paint stratigraphy reveals that arsenic is distributed throughout the entire cross-section, while X-ray absorption near edge structure (μ-XANES) demonstrated that the arsenic is present in both arsenite (As-III) and arsenate (As-V) forms. The latter compound(s), despite being barely identifiable by means of FTIR, were not only located at the surface of large and partially altered grains of arsenic sulfide but also spread throughout the entire paint stratigraphy. Their presence and distribution are attributed either to the complete degradation of smaller arsenic sulfide grains or to migration of the arsenates within the paint layer away from their original location of formation. The combination of μ-XRF and μ-XANES was very useful for the characterization of the advanced degradation state of the arsenic-containing pigments in paint systems; this type of information could not be obtained by means of conventional spectroscopic methods of microanalysis.

L'aventurine, une technique de décoration peinte de l'époque baroque rarement documentée. En restauration de sculptures et d'objets polychromes, on est très souvent confronté à une superposition de plusieurs couches picturales rendant la compréhension de l'original ou d'une autre intervention délicate. La compatibilité des matériaux et techniques de conservation-restauration appliqués à ces œuvres est une des raisons de bien étudier la nature des couches sousjacentes. Pensons, par exemple, aux brocards appliqués à la cire, abîmés par un fixage à chaud, ou à la dénaturation d'une couche mate par un corps gras ou une résine brillante. Dans le cas, où l'on veut remettre à jour une couche ancienne par dégagement des surpeints, la compréhension de la stratigraphie devient primordiale. Une couche transparente se trouvant à la limite entre deux interventions peut aussi bien être considérée comme couche de finition que comme couche d'isolation ou préparatoire...

The Entombment of Christ in the Collegiate Church of St Vincent of Soignies which probably can be dated between 1435 en 1440, is an undisputed masterpiece of the Late Gothic style. More precisely it represents the basis of the Late Gothic style of Tournai, as introduced to the Brussels area by Delemer and Van der Weyden. A style which will become of great infl uence on the artistic developments in that specifi c region. As with all sculptures of this age, the Entombment of Soignies has been subject of previous restorations. The most recent restoration performed in 1970s by KIK-IRPA is documented by restoration reports. This 1970 restoration mostly affected the sculptures’ surroundings. The original setting of this sculpture group consist of the niche with its architectural framing and the mural paintings in the background, which have been exposed in the 1970s. The sculpture group and its niche represent a fascinating unity which is clearly emphasized by the recently executed polychr...

ABSTRACT Surface preparation with gas cluster ion beam (GCIB) sputtering was performed on paint cross-sections, which belong to the collection of the Royal Institute for Cultural Heritage (KIKIRPA), Brussels, Belgium. Superficial cleaning of cross sections with residual embedding resin surface contamination was studied with different sputtering times in order to obtain a gain in the spectral and imaging mode. Sputtering was made directly through the Time-of-Flight-SIMS apparatus. It was thus demonstrated that GCIB sputtering for a short period was very efficient for the superficial decontamination of cultural heritage cross-sections without visible damage on the valuable samples. The GCIB sputtering time and dose can be highly decreased when combined with a monoatomic argon ion beam preparation techniques such as the ion milling systems. Copyright © 2014 John Wiley & Sons, Ltd.

Painted metal knight shields of the Order of the Elephant produced during the last part of the 20th century are characterized by a striking variety in their conservation state. Three different coat systems were identified and investigated by Fourier transform infrared microscopy (μ-FTIR), micro-Raman spectroscopy (MRS), scanning electron microscopy-Energy dispersive X-ray spectroscopy (SEM-EDX) and Thermally assisted hydrolysis and methylation-gas chromatography-mass Spectrometry (THM-GC-MS). Chalking of the white paint layer on the first group of knight shields displayed in the window niches was found to be related to the use of titanium white of the anatase type. A pristine condition of the second group could be attributed to priming of the lead rich metal support with a zinc potassium chromate based primer and the use of mainly stable white pigments in the top coat. Severe delamination of the paint layer of the third group was caused by the formation of lead corrosion products be...

A proteomics approach was used for the identification of protein binders in historical paints: the proteins were digested enzymatically into peptides using trypsin before being separated and detected by high performance liquid chromatography-electrospray ionisation tandem mass spectrometry (HPLC-ESI-MS/MS). Mascot (Matrix Science) was used to analyse the resulting data and for protein identification. In contrast to amino acid analysis, amino acid sequences could be studied that retain much more information about the proteins. The best extraction strategy was selected based on the number of peptides that were identified in the protein content of paint replicas using different methods. The influence of pigments on the extraction method was studied and the analytical characteristics of the selected method were determined. Finally this method was applied to historical paint microsamples on the anonymous early 15th century panel painting Crucifixion with St Catherine and St Barbara (Calvary of the Tanners), the St Catherine Altarpiece by Joes Beyaert (c. 1479) and two paintings by Pieter Brueghel the Younger (1617-1628).