Koen Janssens

University of Antwerp

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Frederik Vanmeert

University of Antwerp

Bart Vekemans

Ghent University

Simone Cagno

Norwegian University of Life Sciences

Steven De Meyer

University of Antwerp

Joost Caen

University of Antwerp

Geert Van der Snickt

University of Antwerp

Wout De Nolf

European Synchrotron Radiation Facility

Roberto Terzano

University of Bari Aldo Moro

Olivier Schalm

Antwerp Maritime Academy

Frank E. Brenker

Goethe University Frankfurt

Cooperative Institutions

Centre National de la Recherche Scientifique

362

California Institute of Technology

305

Université Paris Cité

173

Cardiff University

147

Laboratoire AstroParticule et Cosmologie

143

Max Planck Institute for Gravitational Physics

142

The University of Tokyo

140

LIGO Scientific Collaboration

136

National Institute for Subatomic Physics

127

Massachusetts Institute of Technology

115

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Protection of Stone Monuments Using a Brushing Treatment with Ammonium Oxalate

Coatings (2021)

Domagoj Mudronja Frederik Vanmeert Stjepko Fazinić Koen Janssens Darko Tibljaš

Stone monuments and buildings are susceptible to weathering. Carbonate-based stones are especially vulnerable in acidic environments, whereas magmatic acidic stones are more susceptible to chemical weathering in basic environments. To slow down surface corrosion of limestone and marble artworks/buildings, protective coatings which inhibit calcite dissolution have been proposed. In this work, samples from two stone types with different porosity were treated with ammonium oxalate (AmOx) to create a protective layer of calcium oxalate (CaOx) using the previously developed brushing method. Two different synchrotron microscopy experiments were performed to determine its protective capability. X-ray powder diffraction (SR-μ-XRPD) in transmission geometry allowed visualization of the distributions of calcium carbonate and oxalates along the sample depths. In a second step, X-ray fluorescence (SR-μ-XRF) was used to check the efficiency/integrity of the protective surface coating layer. This was done by measuring the sulfur distribution on the stone surface after exposing the protected stones to sulfuric acid. XRPD showed the formation of a protective oxalate layer with a thickness of 5–15 µm on the less porous stone, while a 20–30 µm thick layer formed on the more porous stone. The XRF study showed that the optimal treatment time depends on the stone porosity. Increasing the treatment time from 1 to 3 h resulted in a decreased efficiency of the protective layer for the low porosity stone. We assume that this is due to the formation of vertical channels (cracks) in the protective layer.

Ammonium oxalate

Ammonium carbonate

10.3390/coatings11040379

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Citations (5)

Efficiency of applying ammonium oxalate for protection of monumental limestone by poultice, immersion and brushing methods

Applied Physics A (2012)

Domagoj Mudronja Frederik Vanmeert K. Hellemans Stjepko Fazinić Koen Janssens

Ammonium oxalate

10.1007/s00339-012-7365-9

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Citations (30)

Reviving degraded colors of yellow flowers in 17th century still life paintings with macro- and microscale chemical imaging

Science Advances (2022)

Nouchka De Keyser Fréderique Broers Frederik Vanmeert Steven De Meyer Francesca Gabrieli

Over time, artist pigments are prone to degradation, which can decrease the readability of the artwork or notably change the artist’s intention. In this article, the visual implication of secondary degradation products in a degraded yellow rose in a still life painting by A. Mignon is discussed as a case study. A multimodal combination of chemical and optical imaging techniques, including noninvasive macroscopic x-ray powder diffraction (MA-XRPD) and macroscopic x-ray fluorescence imaging, allowed us to gain a 3D understanding of the transformation of the original intended appearance of the rose into its current degraded state. MA-XRPD enabled us to precisely correlate in situ formed products with what is optically visible on the surface and demonstrated that the precipitated lead arsenates and arsenolite from the yellow pigment orpiment and the light-induced fading of an organic yellow lake irreversibly changed the artist’s intentional light-shadow modeling.

Microscale chemistry

Macro

10.1126/sciadv.abn6344

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Citations (11)

A methodology for the identification of glass panes of different origin in a single stained glass window: Application on two 13th century windows

Journal of Cultural Heritage (2010)

Olivier Schalm I. De Raedt Joost Caen Koen Janssens

Float glass

Flat glass

Stained glass

10.1016/j.culher.2010.05.004

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Citations (8)

Non-destructive 3D measurements of sandstone’s internal micro-architecture using high resolution micro-CT

Springer eBooks (2008)

Elke Van de Casteele Simone Bugani Mara Camaiti Luciano Morselli Koen Janssens

10.1007/978-3-540-85226-1_419

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Citations (0)

Evidence of early medieval soda ash glass in the archaeological site of San Genesio (Tuscany)

Journal of Archaeological Science (2012)

Simone Cagno L. Favaretto M. Mendera Andrei Izmer Frank Vanhaecke

Volcanic glass

Trace element

Glass Production

Lead glass

10.1016/j.jas.2011.12.031

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Citations (50)

Deeply colored and black-appearing Roman glass: a continued research

Journal of Archaeological Science (2013)

Simone Cagno Peter Cosyns Andrei Izmer Frank Vanhaecke Karin Nys

Colored

10.1016/j.jas.2013.11.003

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Citations (40)

Science Advances (2023)

Fréderique Broers Ige Verslype Koen W. Bossers Frederik Vanmeert Víctor González

The Night Watch , one of the most famous masterpieces by Rembrandt, is the subject of a large research and conservation project. For the conservation treatment, it is of great importance to understand its current condition. Correlated nano-tomography using x-ray fluorescence and ptychography revealed a—so far unknown—lead-containing “layer”, which likely acts as a protective impregnation layer applied on the canvas before the quartz-clay ground was applied. This layer might explain the presence of lead soap protrusions in areas where no other lead components are present. In addition to the three-dimensional elemental mapping, ptychography visualizes and quantifies components not detectable by hard x-ray fluorescence such as the organic fraction and quartz. The first-time use of this combination of synchrotron-based techniques on a historic paint micro-sample shows it to be an important tool to better interpret the results of noninvasive imaging techniques operating on the macroscale.

Lead (geology)

Ptychography

10.1126/sciadv.adj9394

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Citations (6)

Insights into the composition of ancient Egyptian red and black inks on papyri achieved by synchrotron-based microanalyses

Proceedings of the National Academy of Sciences (2020)

Thomas L. Christiansen Marine Cotte Wout De Nolf Elouan Mouro Juan Reyes-Herrera

Significance Ink, invented in ancient Egypt circa 5,000 y ago, is the established and time-honored medium wherewith humankind commits words to writing. A comprehensive synchrotron-based microanalysis of a considerable corpus of ancient Egyptian papyri from the Roman period, inscribed with red and black inks, reveal a hitherto undetected complex composition of inks. Highlighted by the presence of iron, the red color can be attributed to the use of ocher. Unexpectedly, lead is regularly present in both the red and black inks and is associated to phosphate, sulfate, chloride, and carboxylate ions. The analysis shows that lead was probably used as a drier rather than as a pigment, similar to its usage in 15th century Europe during the development of oil paintings.

Inscribed figure

10.1073/pnas.2004534117

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Citations (35)

Microscopic single particle characterization of zeolites synthesized in a soil polluted by copper or cadmium and treated with coal fly ash

Applied Clay Science (2006)

Roberto Terzano Matteo Spagnuolo L. Medici W. Dorriné Koen Janssens

Sodalite

10.1016/j.clay.2006.07.005

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Citations (33)