“XRDUA : crystalline phase distribution maps by two-dimensional scanning and tomographic (micro) X-ray powder diffraction”. de Nolf W, Vanmeert F, Janssens K, Journal of applied crystallography 47, 1107 (2014). http://doi.org/10.1107/S1600576714008218
Abstract: Imaging of crystalline phase distributions in heterogeneous materials, either plane projected or in virtual cross sections of the object under investigation, can be achieved by scanning X-ray powder diffraction employing X-ray micro beams and X-ray-sensitive area detectors. Software exists to convert the two-dimensional powder diffraction patterns that are recorded by these detectors to one-dimensional diffractograms, which may be analysed by the broad variety of powder diffraction software developed by the crystallography community. However, employing these tools for the construction of crystalline phase distribution maps proves to be very difficult, especially when employing micro-focused X-ray beams, as most diffraction software tools have mainly been developed having structure solution in mind and are not suitable for phase imaging purposes. XRDUA has been developed to facilitate the execution of the complete sequence of data reduction and interpretation steps required to convert large sequences of powder diffraction patterns into a limited set of crystalline phase maps in an integrated fashion.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 62
DOI: 10.1107/S1600576714008218
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“Pigment identification by scanning μ-XRF/μ-XRD”. de Nolf W, Vekemans B, Janssens K, van der Snickt G, Falkenberg G (2007).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Echt of namaak? Venetiaans glas uit het oude Antwerpen”. de Raedt I, Janssens K, Veeckman J, De wetenschappelijke bibliotheek 67, 58 (1999)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“On the distinction between 16th and 17th century Venetian glass and façon-de-Venise glass”. de Raedt I, Janssens K, Veeckman J page 95 (2002).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Composition of facon-de-venise and Venetian glass from Antwerp and the Southern Netherlands”. de Raedt I, Janssens K, Veeckman J, Adams F page 346 (2000).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Samenstelling van 15de- tot 17de-eeuwse glazen voorwerpen opgegraven in Antwerpen”. de Raedt I, Janssens K, Veeckman J, Adams F page 89 (1998).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Samenstelling van 15de- tot 17de-eeuwse glazen voorwerpen opgegraven in Antwerpen: deel 1”. de Raedt I, Janssens K, Veeckman J, Adams F, Journaal van de Belgische Vereniging voor Glastechnieken , 9 (1998)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Samenstelling van 15de- tot 17de-eeuwse glazen voorwerpen opgegraven in Antwerpen: deel 2”. de Raedt I, Janssens K, Veeckman J, Adams F, Journaal van de Belgische Vereniging voor Glastechnieken , 5 (1998)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Glass trade in Antwerp during the 15th through 17th century”. de Raedt I, Janssens K, Veeckman J, Adriaens A, Adams F page 38 (2000).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Trace analysis allows to distinguish between Venetian and facon-de-Venise glass vessels of the 16th and 17th century”. de Raedt I, Janssens K, Veeckman J, Vincze L, Vekemans B, Jeffries T, Journal of analytical atomic spectrometry 16, 1012 (2001). http://doi.org/10.1039/B102597J
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.379
Times cited: 49
DOI: 10.1039/B102597J
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“Synchrotron light through ancient glass”. de Raedt I, Vekemans B, Janssens K, Adams F, Europhysics news 31, 15 (2000)
Keywords: A3 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“The consolidation of cracks and fissures in dalle de verre : assessment of selected adhesives”. De Vis K, Caen J, Janssens K, Jacobs P page 43 (2013).
Abstract: Dalle de verre windows, created from 19301940 onwards, consist of glass pieces with a thickness of approximately 2 to 5 cm, set in a matrix of (reinforced) concrete. Besides the degradation of the concrete, the windows suffer mainly from a complex three-dimensional form of cracking of the glass elements. The cracks need to be consolidated in order to ensure stability and improve transparency. A selection of possible adhesives was evaluated: Araldite® 2020, Hxtal NYL-1, Fynebond, Paraloid® B-72, LV740, A18 and OR-G®. An attempt has been made to objectively compare these adhesives using a bench-marking system. None of the adhesives appears to be suitable for in situ application; sufficient penetration of the adhesives can only be realised with the help of vacuum techniques.
Keywords: H2 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
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De Vis K, Cagno S, Van Mol W, Schalm O, Janssens K, Caen J (2012) The decolourization of manganese-stained glass : the conversion reaction and evaluation of its effectiveness. 463–468
Keywords: P2 Proceeding; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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De Vis K, Jacobs P, Caen J, Janssens K (2010) The use of glass bricks in architecture in the 19th and 20th centuries : a case study. 194–201
Keywords: P2 Proceeding; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“The consolidation of cracks in architectural glass and dalle de verre : first assessment of possible adhesives”. De Vis K, Jacobs P, Janssens K, Caen J, (2011)
Keywords: P3 Proceeding; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Dealing with architectural glasses : maintenance, monitoring and emergency treatment”. De Vis K, Janssens K, Jacobs P, Caen J, (2015)
Keywords: P3 Proceeding; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
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“Integrated X-ray fluorescence and diffuse visible-to-near-infrared reflectance scanner for standoff elemental and molecular spectroscopic imaging of paints and works on paper”. Delaney JK, Conover DM, Dooley KA, Glinsman L, Janssens K, Loew M, Heritage science 6, 31 (2018). http://doi.org/10.1186/S40494-018-0197-Y
Abstract: Prior studies have shown the improved ability to identify artists' pigments by combining results from X-ray fluorescence (XRF), which provides elemental information, with reflectance spectroscopy in the visible to near infrared (400-1000 nm) that provides information on electronic transitions. Extending the spectral range of reflectance spectroscopy into the UV, 350-400 nm, allows identification of several white pigments since their electronic transitions occur in this region (e.g., zinc white and rutile and anatase forms of titanium white). Extending the range further into the infrared, out to 2500 nm, provides information on vibrational transitions of various functional groups, such as hydroxyl, carbonate, and methyl groups. This allows better identification of mineral-based pigments and some paint binders. The combination of elemental information with electronic and vibrational transitions provides a more robust method to identify artists' materials in situ. The collection of both sets of spectral information across works of art, such as paintings and works on paper, allows generating a more complete map of artists' materials. Here, we describe a 2-D scanner that simultaneously collects XRF spectra and reflectance spectra from 350 to 2500 nm across the surfaces of works of art. The scanner consists of a stationary, single pixel XRF spectrometer and fiber optic reflectance spectrometer along with a 2-D position-controlled easel that moves the artwork in front of the two detection systems. The dual-mode scanner has been tested on a variety of works of art from illuminated manuscripts (0.1 x 0.1 m(2)) to paintings as large as 1.7 x 1.9 m(2). The scanner is described and two sets of results are presented. The first is the XRF scanning of a large warped panel painting by Andrea del Sarto titled Charity. The second is a combined XRF and reflectance scan of Georges Seurat's painting titled Haymakers at Montfermeil. The XRF was collected at 1 mm spatial sampling and the reflectance spectral data at 3 mm. Combining the results from the data sets was found to enhance the identification of pigments as well as yield distribution maps, in spite of the relatively low reflectance spatial sampling. The elemental and reflectance maps allowed the identification and mapping of lead white, cobalt blue, viridian, ochres, and likely chrome yellow. The maps also provide information on the mixing of pigments. While the reflectance image cube has 10-20x larger spatial samples than desired, the elimination of having to use two hyperspectral cameras to cover the range from 400 to 2500 nm makes for a low cost dual modality scanner.
Keywords: A1 Journal article; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Times cited: 7
DOI: 10.1186/S40494-018-0197-Y
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“Combined macro X-ray fluorescence (MA-XRF) and pulse phase thermography (PPT) imaging for the technical study of panel paintings”. Deleu N, Hillen M, Steenackers G, Borms G, Janssens K, Van der Stighelen K, Van der Snickt G, Talanta : the international journal of pure and applied analytical chemistry 270, 125533 (2024). http://doi.org/10.1016/J.TALANTA.2023.125533
Abstract: Museum staff usually relies on a proven combination of X-ray radiography (XRR) and infrared reflectography (IRR) to study paintings in a non-destructive manner. In the last decades, however, the research toolbox of heritage scientists has expanded considerably, with a prime example being macro X-ray fluorescence (MA-XRF), producing element-specific images. The goal of this article is to illustrate the added value of augmenting MA-XRF with pulse phase thermography (PPT), a variant of active infrared thermographic imaging (IRT), which is an innovative diagnostic method that is able to reveal variations between or in materials, based on a different response to minor fluctuations in temperature when irradiated with optical radiation. By examining three 16thand 17th-century panel paintings we assess the extent in which combined MA-XRF and PPT contributes to a better understanding of two commonly encountered interventions to panel paintings: (a) Anstuckungen (enlargement of the panel) or (b) substitutions (replacement of part of the panel). Yielding information from different depths of the painting, these two techniques proved highly complementary with IRR and XRR, expanding the understanding of the build-up, genesis, and material history of the paintings. While MA-XRF documented the interventions to the wooden substrate indirectly by revealing variations in painting materials, paint handling and/ or layer sequence between the original part and the extended or replaced planks, PPT proved beneficial for the study of the wooden support itself, by providing a clear image of the wood structure quasi-free of distortion by the superimposed paint or cradling. XRR, on the other hand, revealed other features from the wood structure, not visible with PPT, and allowed looking through the wooden panels, revealing e.g. the dowels used for joining the planks. Additionally, IRR visualised dissimilarities in the underdrawings. In this way, the results indicate that PPT has the potential to become an acknowledged add-on to the expanding set of imaging methods for paintings, especially when used in combination with MA-XRF, IRR and XRR.
Keywords: A1 Journal article; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)
Impact Factor: 6.1
DOI: 10.1016/J.TALANTA.2023.125533
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“Spatially resolved micro-X-ray fluorescence and micro-X-ray absorption fine structure study of a fractured granite bore core following a radiotracer experiment”. Denecke MA, Brendebach B, de Nolf W, Falkenberg G, Janssens K, Simon R, Spectrochimica acta: part B : atomic spectroscopy 64, 791 (2009). http://doi.org/10.1016/J.SAB.2009.05.025
Abstract: Spatially resolved X-ray absorption and fluorescence investigation with a micrometer-scale resolution on actinide-containing samples provide information necessary for safety assessment of nuclear waste disposal. In this paper one example of such an experiment is presented. This example entails neptunium speciation in a fractured granite bore core from the Swedish Äspö Hard Rock Laboratory following a radiotracer experiment using µ-XAFS and µ-XRF. In order to probe micro-volumes below the surface in the granite samples and thereby avoid potential changes in the Np speciation during cutting of the bore core, a confocal irradiationdetection geometry is employed. µ-XAFS results for a selected granite bore core cross section with ~ 3 nmol Np/g reveal that Np, originally introduced as Np(V) in the tracer cocktail, is present in the granite in its reduced Np(IV) form. The Np(IV) is often present as particles, tens of µm in size. Elemental distribution maps show the tracer Np to be located in fissures and permeable channels not larger than 100 µm. The Np distribution appears often correlated with Zn also present in some fissures. We observe small granite fissures containing Fe (presumably Fe(II)), where we do not detect any Np. It is feasible that inflowing Np(V) has a shorter residence time in large fractures, while in the smaller fissures migration is slower, leading to longer residence times, i.e., reaction times, where it is reduced to less soluble Np(IV) and becomes thereby immobilized.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.241
Times cited: 21
DOI: 10.1016/J.SAB.2009.05.025
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“mu-X-ray fluorescence and mu-X-ray diffraction investigations of sediment from the Ruprechtov nuclear waste disposal natural analog site”. Denecke MA, de Nolf W, Janssens K, Brendebach B, Falkenberg G, Noseck U, Rothkirch A, Spectrochimica acta: part B : atomic spectroscopy 63, 484 (2008). http://doi.org/10.1016/J.SAB.2008.01.001
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 3.241
Times cited: 7
DOI: 10.1016/J.SAB.2008.01.001
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“Confocal mu-XRF, mu-XAFS, and mu-XRD studies of sediment from a nuclear waste disposal natural analogue site and fractured granite following a radiotracer migration experiment”. Denecke MA, Janssens K, Brendebach B, de Nolf W, Falkenberg G, Rothe J, Simon R, Somogyi A, Vekemans B, Noseck U, AIP conference proceedings 882, 187 (2007)
Abstract: Combined mu-XRF, mu-XAFS, and mu-XRD investigations of a uranium-rich tertiary sediment, from a nuclear repository natural analogue site, and a fractured granite bore core section after a column tracer experiment using a Np(V) containing cocktail have been performed. Most mu-XRF/mu-XAFS measurements are recorded in a confocal geometry to provide added depth information. The U-rich sediment results show uranium to be present as a tetravalent phosphate and that U(IV) is associated with As(V). Arsenic present is either As(V) or As(0). The As(0) form thin coatings on the surface of pyrite nodules. A hypothesis for the mechanism of uranium immobilization is proposed, where arsenopyrite acted as reductant of ground water dissolved U(VI) leading to precipitation of less soluble U(IV) and thereby forming As(V). Results for the granite sample show the immobilized Np to be tetravalent and associated with facture material.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Confocal μ-XRF and μ-XAFS studies of fractured granite following a radiotracer migration experiment”. Denecke MA, Janssens K, Brendebach B, Falkenberg G, de Nolf W, Römer J (2007).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Confocal μ-XRF and μ-XAFS studies on fractured granite following a radiotracer migration experiment”. Denecke MA, Janssens K, Brendebach B, Falkenberg G, Römer J, Simon R, Vekemans B, (2007)
Keywords: P3 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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“Confocal micrometer-scale X-ray fluorescence and X-ray absorption fine structure studies of uranium speciation in a tertiary sediment from a waste disposal natural analogue site”. Denecke MA, Janssens K, Proost K, Rothe J, Noseck U, Environmental science and technology 39, 2049 (2005). http://doi.org/10.1021/ES048644K
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.198
Times cited: 47
DOI: 10.1021/ES048644K
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“Microanalysis (micro-XRF, micro-XANES, and micro-XRD) of a tertiary sediment using microfocused synchrotron radiation”. Denecke MA, Somogyi A, Janssens K, Simon R, Dardenne K, Noseck U, Microscopy and microanalysis 13, 165 (2007). http://doi.org/10.1017/S1431927607070316
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 1.891
Times cited: 31
DOI: 10.1017/S1431927607070316
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“Compositional distinctions between 16th century “Façon-de-Venise&rdquo, and Venetian glass vessels, excavated in Antwerp, Belgium”. Deraedt I, Janssens K, Veeckman J, Journal of analytical atomic spectroscopy 14, 483 (1999). http://doi.org/10.1039/A808385A
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
DOI: 10.1039/A808385A
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“The dark halo technique in the oeuvre of Michael Sweerts and other Flemish and Dutch baroque painters. A 17th c. empirical solution to mitigate the optical 'simultaneous contrast' effect?”.Derks K, van der Snickt G, Legrand S, van der Stighelen K, Janssens K, Heritage science 10, 5 (2022). http://doi.org/10.1186/S40494-021-00634-W
Abstract: Although the topic is rarely addressed in literature, a significant number of baroque paintings exhibit dark, halo-like shapes around the contours of the dramatis personae. Close examination of both finished and unfinished works suggests that this intriguing feature was a practical tool that helped the artist in the early painting stages. When applying the final brushwork, the halo lost its function, with some artists undertaking efforts to hide it. Although their visibility might not have been intended by the artists, today this dark paint beneath the surface is partially visible through the upper paint layers. Moreover, the disclosure of many halos using infrared photography (IRP), infrared reflectography (IRR) and macro X-ray fluorescence imaging (MA-XRF), additional to those that can be observed visually, suggests that this was a common and established element of 17th-century painting practice in Western Europe. Building on an existing hypothesis, we argue that halos can be considered as a solution to an optical problem that arose when baroque painters reversed the traditional, 15th- and 16th-century painting sequence of working from background to foreground. Instead, they started with the dominant parts of a composition, such as the face of a sitter. In that case, a temporary halo can provide the essential tonal reference to anticipate the chromatic impact of the final dark colored background on the adjacent delicate carnations. In particular, we attempt to clarify the prevalence of dark halos as a response to optical effects such as 'simultaneous contrast' and 'the crispening effect', described in literature only centuries later. As such, the recently termed 'ring condition' can be seen as the present-day equivalent of the 'halo solution' that was seemingly empirically or intuitively developed by 17th-century artists. Modern studies in visual perception proves that by laying a black ring around a target color, the optical impact of a surrounding color can be efficiently neutralized. Finally, by delving into works by Michael Sweerts, it becomes clear that resourceful artists might have adapted the halo technique and the underlying principles to their individual challenges, such as dealing with differently colored grounds.
Keywords: A1 Journal article; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)
Impact Factor: 2.5
DOI: 10.1186/S40494-021-00634-W
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“Reconstructing Sweerts : practical insights into the historical dark halo technique based on paint reconstructions”. Derks K, Youchaeva M, Van der Snickt G, Van der Stighelen K, Janssens K, , 259 (2024)
Keywords: P1 Proceeding; Engineering sciences. Technology; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)
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“Visualization of a lost painting by Vincent van Gogh using synchrotron radiation based X-ray fluorescence elemental mapping”. Dik J, Janssens K, van der Snickt G, van der Loeff L, Rickers K, Cotte M, Analytical chemistry 80, 6436 (2008). http://doi.org/10.1021/AC800965G
Abstract: Vincent van Gogh (1853−1890), one of the founding fathers of modern painting, is best known for his vivid colors, his vibrant painting style, and his short but highly productive career. His productivity is even higher than generally realized, as many of his known paintings cover a previous composition. This is thought to be the case in one-third of his early period paintings. Van Gogh would often reuse the canvas of an abandoned painting and paint a new or modified composition on top. These hidden paintings offer a unique and intimate insight into the genesis of his works. Yet, current museum-based imaging tools are unable to properly visualize many of these hidden images. We present the first-time use of synchrotron radiation based X-ray fluorescence mapping, applied to visualize a womans head hidden under the work Patch of Grass by Van Gogh. We recorded decimeter-scale, X-ray fluorescence intensity maps, reflecting the distribution of specific elements in the paint layers. In doing so we succeeded in visualizing the hidden face with unprecedented detail. In particular, the distribution of Hg and Sb in the red and light tones, respectively, enabled an approximate color reconstruction of the flesh tones. This reconstruction proved to be the missing link for the comparison of the hidden face with Van Goghs known paintings. Our approach literally opens up new vistas in the nondestructive study of hidden paint layers, which applies to the oeuvre of Van Gogh in particular and to old master paintings in general.
Keywords: A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
Impact Factor: 6.32
Times cited: 178
DOI: 10.1021/AC800965G
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“High-E scanning m-XRF experiment on test paintings”. Dik J, Janssens K, van der Snickt G, Wallert A, Rickers K, Falkenberg G page 1589 (2008).
Keywords: H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
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