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	Author	Caen, J.; Schalm, O.; van der Snickt, G.; van der Linden, V.; Frederickx, P.; Schryvers, D.; Janssens, K.; Cornelis, E.; van Dyck, D.; Schreiner, M.
	Title	Enamels in stained-glass windows : preparation, chemical composition, microstructure and causes of deterioration			Type	P3 Proceeding
	Year	2005	Publication		Abbreviated Journal
	Volume		Issue		Pages	121-126
	Keywords	P3 Proceeding; Art; Electron microscopy for materials research (EMAT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Vision lab
	Abstract
	Address
	Corporate Author				Thesis
	Publisher	Glassac	Place of Publication	Lisbon	Editor
	Language		Wos		Publication Date	0000-00-00
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	Most recent IF: NA
	Call Number	UA @ lucian @ c:irua:112025			Serial	1036
Permanent link to this record



	Author	de Nolf, W.; Jaroszewicz, J.; van der Snickt, G.; Janssens, K.; Farnell, S.; Klaassen, L.
	Title	Combined micro-XRF/XRPD tomography on historical and modern paint multilayer samples at Beamline L			Type	H3 Book chapter
	Year	2008	Publication		Abbreviated Journal
	Volume		Issue		Pages	1633-1634
	Keywords	H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:74475			Serial	5522
Permanent link to this record



	Author	Dik, J.; Janssens, K.; van der Snickt, G.; Wallert, A.; Rickers, K.; Falkenberg, G.
	Title	High-E scanning m-XRF experiment on test paintings			Type	H3 Book chapter
	Year	2008	Publication		Abbreviated Journal
	Volume		Issue		Pages	1589-1590
	Keywords	H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:74469			Serial	5638
Permanent link to this record



	Author	Caen, J.; Legrand, S.; van der Snickt, G.; Janssens, K.
	Title	Macro X-ray fluorescence (MA-XRF) scanning : a new and efficient method for documenting stained-glass panels			Type	P3 Proceeding
	Year	2015	Publication		Abbreviated Journal
	Volume		Issue		Pages
	Keywords	P3 Proceeding; Engineering sciences. Technology; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN	978-2-9543731-1-9	Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:126832			Serial	5697
Permanent link to this record



	Author	de Nolf, W.; Vekemans, B.; Janssens, K.; van der Snickt, G.; Falkenberg, G.
	Title	Pigment identification by scanning μ-XRF/μ-XRD			Type	H3 Book chapter
	Year	2007	Publication		Abbreviated Journal
	Volume		Issue		Pages
	Keywords	H3 Book chapter; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:64595			Serial	5773
Permanent link to this record



	Author	Clerici, E.A.; De Meyer, S.; van der Snickt, G.; Janssens, K.
	Title	Synchroton X-ray powder diffraction study of lead white oxidation by sodium hypochloride			Type	P1 Proceeding
	Year	2017	Publication		Abbreviated Journal
	Volume		Issue		Pages	13-27
	Keywords	P1 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	978-80-87108-75-8	ISBN		Additional Links	UA library record; WoS full record
	Impact Factor		Times cited		Open Access
	Notes	; ;			Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:157219			Serial	5860
Permanent link to this record



	Author	Vanmeert, F.; De Meyer, S.; Gestels, A.; Clerici, E.A.; Deleu, N.; Legrand, S.; Van Espen, P.; Van der Snickt, G.; Alfeld, M.; Dik, J.; Monico, L.; De Nolf, W.; Cotte, M.; Gonzalez, V.; Saverwyns, S.; Depuydt-Elbaum, L.; Janssens, K.
	Title	Non-invasive and non-destructive examination of artists’ pigments, paints and paintings by means of X-ray imaging methods			Type	H1 Book chapter
	Year	2022	Publication		Abbreviated Journal
	Volume		Issue		Pages	317-357
	Keywords	H1 Book chapter; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)
	Abstract	Recent studies in which X-ray beams of (sub)micrometre to millimetre dimensions have been used for non-destructive analysis and characterization of pigments, minute paint samples and/or entire paintings from fifteenth to twentieth century artists are discussed. The overview presented encompasses the use of laboratory and synchrotron radiation-based instrumentation and deals with the use of several variants of X-ray fluorescence (XRF) as a method of elemental analysis and imaging as well as with the combined use with X-ray diffraction (XRD). Microscopic XRF (μ-XRF) is a variant of the XRF method able to visualize the elemental distribution of key elements, mostly metals, on the scale from 1 μm to 100 μm present inside multi-layered micro samples taken from paintings. In the context of the characterization of artists’ pigments subjected to natural degradation, in many cases the use of methods limited to elemental analysis or imaging does not suffice to elucidate the chemical transformations that have taken place. However, at synchrotron facilities, combinations of μ-XRF with related methods such as μ-XAS (microscopic X-ray absorption spectroscopy) and μ-XRD have proven themselves to be very suitable for such studies. Since microscopic investigation of a relatively limited number of minute paint samples may not yield representative information about the complete artefact they were taken from, several methods for macroscopic, non-invasive imaging have recently been developed. Combined macroscopic XRF/XRD scanning is able to provide a fairly complete overview of the inorganic pigments employed to create a work of art, to answer questions about ongoing degradation phenomena and about its authenticity. As such these newly developed non-invasive and highly specific imaging methods are of interest for many cultural heritage stakeholders.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2022-09-08
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN	978-3-030-86864-2	Additional Links	UA library record
	Impact Factor		Times cited		Open Access	Not_Open_Access
	Notes				Approved	Most recent IF: NA
	Call Number	UA @ admin @ c:irua:190777			Serial	7183
Permanent link to this record



	Author	Klaassen, L.; van der Snickt, G.; Legrand, S.; Higgitt, C.; Spring, M.; Vanmeert, F.; Rosi, F.; Brunetti, B.G.; Postec, M.; Janssens, K.
	Title	Characterization and removal of a disfiguring oxalate crust on a large altarpiece by Hans Memling			Type	H1 Book chapter
	Year	2019	Publication		Abbreviated Journal
	Volume		Issue		Pages	263-282 T2 - Metal soaps in art / Casadio, F. [edi
	Keywords	H1 Book chapter; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
	Abstract	During the conservation treatment of Memling’s Christ with Singing and Music-making Angels, three panel paintings that are among the most monumental works in early Netherlandish art, the conservators came across insoluble surface layers containing calcium oxalates. A very thin and irregular layer of this type, hardly visible to the naked eye, was spread across the surface of all three panels. A much thicker layer forming an opaque and highly disfiguring crust that obscured the composition (Figs. 15.1 and 15.7) was locally present on areas of dark copper-containing paint, where multiple layers of old discolored coatings and accretions remained in place before the most recent cleaning. This article describes the application of a wide range of analytical techniques in order to fully understand the stratigraphy and composition of the crusts on the Memling paintings. FTIR spectroscopy in transmission and reflection mode, micro-ATR-FTIR imaging and macro-rFTIR scanning, SEM-EDX, mobile XRD, and SR-μXRD showed that the crusts contained two related Ca-based oxalate salts, whewellite and weddellite, and were separated from the original paint surface by varnish, indicating that they did not originate from degradation of the original paint but from a combination of microbial action and a thick accumulation of dirt. Supported by the results from these different analytical techniques, which when used together proved to be very effective in providing complementary information that addressed this specific conservation problem, and aided by the presence of the intermediate varnish layer(s), the conservators were able to remove most of the crusts with spectacular results.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2019-03-23
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN	978-3-319-90616-4	Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:190778			Serial	7609
Permanent link to this record



	Author	Monico, L.; Hendriks, E.; Geldof, M.; Miliani, C.; Janssens, K.; Brunetti, B.G.; Cotte, M.; Vanmeert, F.; Chieli, A.; Van der Snickt, G.; Romani, A.; Melo, M.J.
	Title	Chemical alteration and colour changes in the Amsterdam sunflowers			Type	H1 Book chapter
	Year	2019	Publication		Abbreviated Journal
	Volume		Issue		Pages	125-158 T2 - Van Gogh’s Sunflowers illuminated – a
	Keywords	H1 Book chapter; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
	Abstract	This chapter provides a description of colour changes in the Amsterdam Sunflowers due to chemical alteration of pigments, with a focus on geranium lakes and chrome yellows. The brilliant and forceful colours of these and other late nineteenth-century synthetic materials offered artists such as Vincent van Gogh new means of artistic expression that exploited a range of contrasting hues and tints. However, geranium lakes have a strong tendency to fade and chrome yellows to darken under the influence of light. Van Gogh, like other artists of his day, was aware of this drawback, yet he continued to favour the use of both pigments up until his death in July 1890 due to the unparalleled effects they gave. In April 1888, Vincent wrote to his brother Theo: Van Gogh's use of unstable colours opens a series of questions regarding the extent to which colour change affects the way his paintings look today, as discussed here in relation to the Amsterdam Sunflowers. Furthermore, given the frequency with which geranium lakes and chrome yellows occur in Van Gogh's paintings of the period 1888–90 and the predominance of chrome yellows in Sunflowers, it becomes important to understand the factors that can drive these processes of deterioration in order to develop appropriate strategies for conserving the artist's works.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2020-11-25
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN	978-94-6372-532-3	Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:190779			Serial	7640
Permanent link to this record



	Author	Hendriks, E.; Geldof, M.; van den Berg, K.J.; Monico, L.; Miliani, C.; Moretti, P.; Iwanicka, M.; Targowski, P.; Megens, L.; de Groot, S.; van Keulen, H.; Janssens, K.; Vanmeert, F.; van der Snickt, G.
	Title	Conservation of the Amsterdam sunflowers : from past to future			Type	H1 Book chapter
	Year	2019	Publication		Abbreviated Journal
	Volume		Issue		Pages	175-205 T2 - Van Gogh’s Sunflowers illuminated – a
	Keywords	H1 Book chapter; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
	Abstract	This chapter lays out a conservation timeline, from past to future, for the Amsterdam version of Van Gogh's Sunflowers. It starts by considering the restoration history of the painting in order to assess its current physical state, and looks ahead to formulate an appropriate strategy for future conservation treatment and display. Due attention is paid to the two recorded episodes of restoration performed in 1927 and 1961 by the Dutch restorer, Jan Cornelis Traas. Based on physical and chemical investigation of Sunflowers we attempt to reconstruct what these former treatments (which are barely documented) entailed and consider the repercussions for the present condition of the painting. The former interventions by Traas also serve as a benchmark to reflect on current choices made, highlighting the extent to which ideas and methodologies have continued to evolve over the past century as conservation has moved further away from being a singularly craft-based activity to become an established historical and scientific discipline underpinned by ethical guidelines. Jan Cornelis Traas (1898–1984) As mentioned, the two main recorded interventions to the Amsterdam Sunflowers may be associated with the Dutch restorer, Jan Cornelis Traas, who treated the picture in 1927, close to the start of his career, and again in 1961, shortly before he retired. Traas was the first restorer to be appointed at the Mauritshuis in The Hague where he worked from 1931 to 1962 and treated hundreds of paintings, including iconic masterpieces such as Girl with a Pearl Earring by Johannes Vermeer. Yet despite the magnitude and importance of his restoration oeuvre, J.C. Traas (as he is usually referred to in surviving documents), has remained somewhat obscure. He is shown here in the only known surviving photograph of him at work, shortly before he retired (fig. 7.1). Unlike his illustrious contemporaries, A. Martin de Wild (1899–1969) and Helmut Ruhemann (1891–1973), for example, Traas did not publish anything, he appears to have kept no records of his work and no personal archive is known. However, the study of some newly discovered historical documents, combined with physical examination of Sunflowers and a large number of other works he treated, allows us to recover an idea of his working practices and approaches viewed within the context of his day.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2020-11-25
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN	978-94-6372-532-3	Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:190780			Serial	7727
Permanent link to this record



	Author	Janssens, K.; Alfeld, M.; Van der Snickt, G.; De Nolf, W.; Vanmeert, F.; Monico, L.; Legrand, S.; Dik, J.; Cotte, M.; Falkenberg, G.; van der Loeff, L.; Leeuwestein, M.; Hendriks, E.
	Title	Examination of Vincent van Gogh's paintings and pigments by means of state-of-the-art analytical methods			Type	H2 Book chapter
	Year	2014	Publication		Abbreviated Journal
	Volume		Issue		Pages	373-403 T2 - Science and art : the painted surface
	Keywords	H2 Book chapter; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	Recent studies in which X-ray beams of macroscopic to (sub) microscopic dimensions were used for non-destructive analysis and characterization of pigments, paint micro samples and/or entire paintings by Vincent van Gogh are concisely reviewed. The overview presented encompasses the use of laboratory and synchrotron radiation-based instrumentation and deals with the use of several variants of X-ray fluorescence (XRF) as a method of elemental analysis and imaging as well as with the combined use of X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS). Microscopic and macroscopic XRF are variants of the method that are well suited to visualize the elemental distribution of key elements, mostly metals, present in paint multi layers, either on the length scale from 1–100 μm inside micro samples taken from paintings or on the 1–100 cm length scale when the (subsurface) distribution of specific pigments in entire paintings is concerned. In the context of the characterization of van Gogh's pigments subject to natural degradation, the use of methods limited to elemental analysis or imaging usually is not sufficient to elucidate the chemical transformations that have taken place. However, at synchrotron facilities, combinations of μ-XRF with related methods such as μ-XAS and μ-XRD have proven themselves to be very suitable for such studies. Their use is often combined with microscopic Fourier transform infra-red (μ-FTIR) spectroscopy since this method delivers complementary information at more or less the same length scale as the X-ray microprobe techniques. Also in the context of macroscopic imaging of works of art, the complementary use of X-ray based and infra-red based imaging appears very promising; some recent developments are discussed.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2020-02-24
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN	978-1-84973-818-7	Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:190782			Serial	7943
Permanent link to this record



	Author	van der Snickt, G.
	Title	James Ensor's pigments studied by means of portable and synchrotron radiation-based X-ray techniques : evolution, context and degradation			Type	Doctoral thesis
	Year	2012	Publication		Abbreviated Journal
	Volume		Issue		Pages	501 p.
	Keywords	Doctoral thesis; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN		Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:100628			Serial	8135
Permanent link to this record



	Author	Geldof, M.; Monico, L.; Johnson, D.H.; Miliani, C.; Romani, A.; Grazia, C.; Buti, D.; Brunetti, B.G.; Janssens, K.; Van der Snickt, G.; Vanmeert, F.
	Title	Methods and materials of the Amsterdam sunflowers			Type	H1 Book chapter
	Year	2019	Publication		Abbreviated Journal
	Volume		Issue		Pages	85-123 T2 - Van Gogh’s Sunflowers illuminated – ar
	Keywords	H1 Book chapter; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation); Antwerp Cultural Heritage Sciences (ARCHES)
	Abstract	This chapter explains the materials and techniques employed in the Amsterdam Sunflowers, enabling a comparison with the London version described in chapter 3. Building upon the 2016 article published in the National Gallery Technical Bulletin, it incorporates the latest findings gained by computer-assisted methods used to characterize the canvas support, as well as in-situ campaigns of non-invasive investigation together with further analysis of microscopic paint samples. The chapter sequence follows the steps in Van Gogh's working practice. Starting with the canvas, automated analysis of the weave enables the provenance of the canvas to be traced back to a particular roll of linen ordered by Van Gogh. Combining technical evidence with knowledge of historical manufacturing techniques further allows us to reconstruct the way in which Van Gogh divided his canvas roll into pieces used for Sunflowers and other paintings. We go on to consider how, with the original painting at hand, he used charcoal to transfer the motif of the London Sunflowers onto his blank canvas. Despite careful planning of the composition, an adjustment was required late in the working process, when Van Gogh added a painted wooden strip to extend the background above the flower at the top edge of the canvas. The artist's process of working up the composition in paint is described, paying special attention to his use of colour. The pigments and pigment mixtures used in the Amsterdam Sunflowers have been comprehensively mapped and are compared with the London picture, with discussion of some similarities and differences that account for the distinctive colour scheme of each painting. This understanding of colour application in the Amsterdam Sunflowers lays the foundation for subsequent chapters that will go on to consider the impact of light-induced colour changes that have taken place over time, and the related need to define appropriate lighting guidelines for the future safe preservation of this painting and others made with similar materials (chapters 5 and 7).
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date	2020-11-25
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN	978-94-6372-532-3	Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:190781			Serial	8223
Permanent link to this record



	Author	van der Snickt, G.; de Boeck, A.; Keutgens, K.; Anthierens, D.
	Title	The SALUT project : study of advanced laser techniques for the uncovering of polychromed works of art			Type	P1 Proceeding
	Year	2007	Publication		Abbreviated Journal
	Volume	116	Issue		Pages	151-158 T2 - Proceedings of the 6th International
	Keywords	P1 Proceeding; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	In order to find out whether the existing laser systems can be employed to remove superimposed layers of paint on secco wall paintings in a selective way, laser tests were carried out on three types of prepared samples simulating three stratigraphies that are frequently encountered in practice. OM, EPMA, colorimetry, mu Raman, and FT-IR were used to evaluate the results. It was found that Q-switched Nd:YAG lasers emitting at 1,064 nm could be employed to remove unwanted layers of oil paint and limewash, but the treatment of large areas requires implementation of a computer-controlled X-Y-Z station in order to control the parameters. However, the applicability of this technique will remain limited as ablation at the established optimum parameters implied a discoloration of the pigments cinnabar, yellow ochre, and burnt sienna. Moreover, it was observed that no ablation took place when the limewash thickness exceeds 25 mu m. Unwanted layers of acrylic could be removed in an efficient way with an excimer laser emitting at 193 nm.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000252680500018	Publication Date
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	978-3-540-72129-1; 0930-8989	ISBN		Additional Links	UA library record; WoS full record
	Impact Factor		Times cited		Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:157216			Serial	8491
Permanent link to this record



	Author	Vanmeert, F.; Van der Snickt, G.; Legrand, S.; Janssens, K.
	Title	Velázquez? A portrait of Pope Innocent X : an X-ray imaging investigation (II)			Type	H3 Book chapter
	Year	2019	Publication		Abbreviated Journal
	Volume		Issue		Pages	132-141 T2 - Velázquez : Anregungen, Vorschläge, L
	Keywords	H3 Book chapter; Art; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	Encompassing a broad spectrum of methodological approaches and aims, the scholars contributing to this volume offer renewed perspectives on the multifaceted oeuvre of Diego Velázquez. The seventeenth-century artist’s exceptional religious works as well as his numerous portraits are examined within the social and historical context of Velázquez’s milieu which included both the Spanish court as well as circles comprising important intellectual figures of his time. Following a close investigation of his works, which also includes the results of recent technological examinations on his paintings, the contributors to this volume offer new, exciting findings and discussions on the inspirations, sources and possible intentions of Velázquez.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN		ISBN	978-3-99020-155-8	Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:190783			Serial	8736
Permanent link to this record



	Author	Derks, K.; Youchaeva, M.; Van der Snickt, G.; Van der Stighelen, K.; Janssens, K.
	Title	Reconstructing Sweerts : practical insights into the historical dark halo technique based on paint reconstructions			Type	P1 Proceeding
	Year	2024	Publication		Abbreviated Journal
	Volume		Issue		Pages	259-271 T2 - Alla maniera : technical art history
	Keywords	P1 Proceeding; Engineering sciences. Technology; Art; Antwerp Cultural Heritage Sciences (ARCHES); Antwerp X-ray Imaging and Spectroscopy (AXIS)
	Abstract
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos		Publication Date
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	978-90-429-5216-4	ISBN		Additional Links	UA library record
	Impact Factor		Times cited		Open Access
	Notes				Approved	no
	Call Number	UA @ admin @ c:irua:203062			Serial	9082
Permanent link to this record



	Author	Monico, L.; van der Snickt, G.; Janssens, K.; de Nolf, W.; Miliani, C.; Verbeeck, J.; Tian, H.; Tan, H.; Dik, J.; Radepont, M.; Cotte, M.
	Title	Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of synchrotron X-ray spectromicroscopy and related methods : 1 : artificially aged model samples			Type	A1 Journal article
	Year	2011	Publication	Analytical chemistry	Abbreviated Journal	Anal Chem
	Volume	83	Issue	4	Pages	1214-1223
	Keywords	A1 Journal article; Electron microscopy for materials research (EMAT); AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	On several paintings by artists of the end of the 19th century and the beginning of the 20th Century a darkening of the original yellow areas, painted with the chrome yellow pigment (PbCrO4, PbCrO4·xPbSO4, or PbCrO4·xPbO) is observed. The most famous of these are the various Sunflowers paintings Vincent van Gogh made during his career. In the first part of this work, we attempt to elucidate the degradation process of chrome yellow by studying artificially aged model samples. In view of the very thin (1−3 μm) alteration layers that are formed, high lateral resolution spectroscopic methods such as microscopic X-ray absorption near edge (μ-XANES), X-ray fluorescence spectrometry (μ-XRF), and electron energy loss spectrometry (EELS) were employed. Some of these use synchrotron radiation (SR). Additionally, microscopic SR X-ray diffraction (SR μ-XRD), μ-Raman, and mid-FTIR spectroscopy were employed to completely characterize the samples. The formation of Cr(III) compounds at the surface of the chrome yellow paint layers is particularly observed in one aged model sample taken from a historic paint tube (ca. 1914). About two-thirds of the chromium that is present at the surface has reduced from the hexavalent to the trivalent state. The EELS and μ-XANES spectra are consistent with the presence of Cr2O3·2H2O (viridian). Moreover, as demonstrated by μ-XANES, the presence of another Cr(III) compound, such as either Cr2(SO4)3·H2O or (CH3CO2)7Cr3(OH)2 [chromium(III) acetate hydroxide], is likely.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication	Washington, D.C.	Editor
	Language		Wos	000287176900011	Publication Date	2011-02-14
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-2700;1520-6882;	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.32	Times cited	113	Open Access
	Notes	Iuap; Fwo			Approved	Most recent IF: 6.32; 2011 IF: 5.856
	Call Number	UA @ lucian @ c:irua:88794UA @ admin @ c:irua:88794			Serial	632
Permanent link to this record



	Author	van der Snickt, G.; Dik, J.; Cotte, M.; Janssens, K.; Jaroszewicz, J.; de Nolf, W.; Groenewegen, J.; van der Loeff, L.
	Title	Characterization of a degraded cadmium yellow (CdS) pigment in an oil painting by means of synchrotron radiation based X-ray techniques			Type	A1 Journal article
	Year	2009	Publication	Analytical chemistry	Abbreviated Journal	Anal Chem
	Volume	81	Issue	7	Pages	2600-2610
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	On several paintings of James Ensor (1860−1949), a gradual fading of originally bright yellow areas, painted with the pigment cadmium yellow (CdS), is observed. Additionally, in some areas exposed to light, the formation of small white-colored globules on top of the original paint surface is observed. In this paper the chemical transformation leading to the color change and to the formation of the globules is elucidated. Microscopic X-ray absorption near-edge spectroscopy (ì-XANES) experiments show that sulfur, originally present in sulfidic form (S2−), is oxidized during the transformation to the sulfate form (S6+). Upon formation (at or immediately below the surface), the highly soluble cadmium sulfate is assumed to be transported to the surface in solution and reprecipitates there, forming the whitish globules. The presence of cadmium sulfate (CdSO4·2H2O) and ammonium cadmium sulfate [(NH4)2Cd(SO4)2] at the surface is confirmed by microscopic X-ray diffraction measurements, where the latter salt is suspected to result from a secondary reaction of cadmium sulfate with ammonia. Measurements performed on cross sections reveal that the oxidation front has penetrated into the yellow paint down to ca. 1−2 ìm. The morphology and elemental distribution of the paint and degradation product were examined by means of scanning electron microscopy equipped with an energy-dispersive spectrometer (SEM-EDS) and synchrotron radiation based micro-X-ray fluorescence spectrometry (SR ì-XRF). In addition, ultraviolet-induced visible fluorescence photography (UIVFP) revealed itself to be a straightforward technique for documenting the occurrence of this specific kind of degradation on a macroscale by painting conservators.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000264759400025	Publication Date	2009-03-11
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-2700; 5206-882x	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.32	Times cited	91	Open Access
	Notes				Approved	Most recent IF: 6.32; 2009 IF: 5.214
	Call Number	UA @ admin @ c:irua:76415			Serial	5501
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	Author	van der Snickt, G.; Janssens, K.; Dik, J.; de Nolf, W.; Vanmeert, F.; Jaroszewicz, J.; Cotte, M.; Falkenberg, G.; Van der Loeff, L.
	Title	Combined use of synchrotron radiation based micro-X-ray fluorescence, micro-X-ray diffraction, micro-X-ray absorption near-edge, and micro-fourier transform infrared spectroscopies for revealing an alternative degradation pathway of the pigment cadmium yellow in a painting by Van Gogh			Type	A1 Journal article
	Year	2012	Publication	Analytical chemistry	Abbreviated Journal	Anal Chem
	Volume	84	Issue	23	Pages	10221-10228
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	Over the past years a number of studies have described the instability of the pigment cadmium yellow (CdS). In a previous paper we have shown how cadmium sulfide on paintings by James Ensor oxidizes to CdSO4 center dot H2O. The degradation process gives rise to the fading of the bright yellow color and the formation of disfiguring white crystals that are present on the paint surface in approximately 50 mu m sized globular agglomerations. Here, we study cadmium yellow in the painting “Flowers in a blue vase” by Vincent van Gogh. This painting differs from the Ensor case in the fact that (a) a varnish was superimposed onto the degraded paint surface and (b) the CdS paint area is entirely covered with an opaque crust. The latter obscures the yellow color completely and thus presents a seemingly more advanced state of degradation. Analysis of a cross-sectioned and a crushed sample by combining scanning microscopic X-ray diffraction (mu-XRD), microscopic X-ray absorption near-edge spectroscopy (mu-XANES), microscopic X-ray fluorescence (mu-XRF) based chemical state mapping and scanning microscopic Fourier transform infrared (mu-FT-IR) spectrometry allowed unravelling the complex alteration pathway. Although no crystalline CdSO4 compounds were identified on the Van Gogh paint samples, we conclude that the observed degradation was initially caused by oxidation of the original CdS pigment, similar as for the previous Ensor case. However, due to the presence of an overlying varnish containing lead-based driers and oxalate ions, secondary reactions took place. In particular, it appears that upon the photoinduced oxidation of its sulfidic counterion, the Cd2+ ions reprecipitated at the paint/varnish interface after having formed a complex with oxalate ions that themselves are considered to be degradation products of the resin and/or oil in the varnish. The SO42- anions, for their part, found a suitable reaction partner in Pb2+ ions stemming from a dissolved lead-based siccative that was added to the varnish to promote its drying. The resulting opaque anglesite compound in the varnish, in combination with the underlying CdC2O4 layer at the paint/varnish interface, account for the orange-gray crust that is disfiguring the painting on a macroscopic level. In this way, the results presented in this paper demonstrate how, through a judicious combined use of several microanalytical methods with speciation capabilities, many new insights can be obtained from two minute, but highly complex and heterogeneous paint samples.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000311815300013	Publication Date	2012-08-30
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-2700; 5206-882x	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.32	Times cited	59	Open Access
	Notes	; This research was supported by BELSPO via the Interuniversity Attraction Poles Programme (IUAP VI/16) and the S2-ART project (SD/RI/04A) and funded by Grants from the ESRF (EC-442) and PETRA-III (I-20120312 EC). The text also presents results of GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and from FWO (Brussels, Belgium) project nos. G.0103.04, G.0689.06, and G.0704.08. The staff of the Kroller-Muller Museum and painting conservators Margje Leeuwestein and Esther Van Duijn are acknowledged for this pleasant cooperation and the authorization for the publication of the images in this article. ;			Approved	Most recent IF: 6.32; 2012 IF: 5.695
	Call Number	UA @ admin @ c:irua:105971			Serial	5526
Permanent link to this record



	Author	Monico, L.; Janssens, K.; Miliani, C.; van der Snickt, G.; Brunetti, B.G.; Guidi, M.C.; Radepont, M.; Cotte, M.
	Title	Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods : 4 : artificial aging of model samples of co-precipitates of lead chromate and lead sulfate			Type	A1 Journal article
	Year	2013	Publication	Analytical chemistry	Abbreviated Journal	Anal Chem
	Volume	85	Issue	2	Pages	860-867
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	Previous investigations about the darkening of chrome yellow pigments revealed that this form of alteration is attributable to a reduction of the original Cr(VI) to Cr(III), and that the presence of sulfur-containing compounds, most often sulfates, plays a key role during this process. We recently demonstrated that different crystal forms of chrome yellow pigments (PbCrO4 and PbCr1xSxO4) are present in paintings by Vincent van Gogh. In the present work, we show how both the chemical composition and the crystalline structure of lead chromate-based pigments influence their stability. For this purpose, oil model samples made with in-house synthesized powders of PbCrO4 and PbCr1xSxO4 were artificially aged and characterized. We observed a profound darkening only for those paint models made with PbCr1xSxO4, rich in SO42 (x ≥ 0.4), and orthorhombic phases (>30 wt %). Cr and S K-edge micro X-ray absorption near edge structure investigations revealed in an unequivocal manner the formation of up to about 60% of Cr(III)-species in the outer layer of the most altered samples; conversely, independent of the paint models chemical composition, no change in the S-oxidation state was observed. Analyses employing UVvisible diffuse reflectance and Fourier transform infrared spectroscopy were performed on unaged and aged model samples in order to obtain additional information on the physicochemical changes induced by the aging treatment.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000313668400032	Publication Date	2012-10-10
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-2700; 5206-882x	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.32	Times cited	49	Open Access
	Notes	; This research was supported by grants from ESRF (experiment EC-799), the Interuniversity Attraction Poles Programme-Belgian Science Policy (IUAP VI/16), and the BELSPO-SDD S2-ART (SD/RI/04) project. The text also presents results from GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and FWO (Brussels, Belgium) projects G.0704.08 and G.01769.09. The EU FP7 programme CHARISMA (Grant Agreement 228330) and MIUR (PRIN08, Materiali e sistemi innovativi per la conservazione dell'arte contemporanea 2008 FFXXN9) are also acknowledged. ;			Approved	Most recent IF: 6.32; 2013 IF: 5.825
	Call Number	UA @ admin @ c:irua:110471			Serial	5569
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	Author	Monico, L.; Janssens, K.; Vanmeert, F.; Cotte, M.; Brunetti, B.G.; van der Snickt, G.; Leeuwestein, M.; Plisson, J.S.; Menu, M.; Miliani, C.
	Title	Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of spectromicroscopic methods : part 5 : effects of nonoriginal surface coatings into the nature and distribution of chromium and sulfur species in chrome yellow paints			Type	A1 Journal article
	Year	2014	Publication	Analytical chemistry	Abbreviated Journal	Anal Chem
	Volume	86	Issue	21	Pages	10804-10811
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	The darkening of lead chromate yellow pigments, caused by a reduction of the chromate ions to Cr(III) compounds, is known to affect the appearance of several paintings by Vincent van Gogh. In previous papers of this series, we demonstrated that the darkening is activated by light and depends on the chemical composition and crystalline structure of the pigments. In this work, the results of Part 2 are extended and complemented with a new study aimed at deepening the knowledge of the nature and distribution of Cr and S species at the interface between the chrome yellow paint and the nonoriginal coating layer. For this purpose, three microsamples from two varnished paintings by Van Gogh and a waxed low relief by Gauguin (all originally uncoated) have been examined. Because nonoriginal coatings are often present in artwork by Van Gogh and contemporaries, the understanding of whether or not their application has influenced the morphological and/or physicochemical properties of the chrome yellow paint underneath is relevant in view of the conservation of these masterpieces. In all the samples studied, microscopic X-ray fluorescence (mu-XRF) and X-ray absorption near edge structure (mu-XANES) investigations showed that Cr(III)-based alteration products are present in the form of grains inside the coating (generally enriched of S species) and also homogeneously widespread at the paint surface. The distribution of Cr(III) species may be explained by the mechanical friction caused by the coating application by brush that picked up and redistributed the superficial Cr compounds, likely already present in the reduced state as result of the photodegradation process. The analysis of the XANES profiles allowed us to obtain new insights into the nature of the Cr(III) alteration products, that were identified as sulfate-, oxide-, organo-metal-, and chloride-based compounds. Building upon the knowledge acquired through the examination of original paint samples and from the investigation of aged model paints in the last Part 4 paper, in this study we aim to characterize a possible relation between the chemical composition of the coating and the chrome yellow degradation pathways by studying photochemically aged model samples covered with a dammar varnish contaminated with sulfide and sulfate salts. Cr speciation results did not show any evidence of the active role of the varnish and added S species on the reduction process of chrome yellows.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000344510200043	Publication Date	2014-10-10
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-2700; 5206-882x	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.32	Times cited	25	Open Access
	Notes	; This research was supported by the Italian projects PRIN (SICH) and PON (ITACHA). The text also presents results from Interuniversity Attraction Poles Programme Belgian Science Policy (S2-ART project S4DA), GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and FWO (Brussels, Belgium) projects no. G.0704.08 and G.01769.09. ESRF is acknowledged for the grants received (experiments EC-799 and EC-1051). L.M. acknowledges the CNR for the financial support received in the framework of the Short Term Mobility Programme 2013. Thanks are expressed to Ella Hendriks (Van Gogh Museum, Amsterdam) and Muriel Geldof (Cultural Heritage Agency of The Netherlands) for selecting and sharing the information on the cross-section taken from Bank of the Seine. All the staff of the Van Gogh Museum, the Kroller-Muller Museum, and the Musee d'Orsay are acknowledged for the agreeable cooperation. ;			Approved	Most recent IF: 6.32; 2014 IF: 5.636
	Call Number	UA @ admin @ c:irua:122100			Serial	5570
Permanent link to this record



	Author	Monico, L.; van der Snickt, G.; Janssens, K.; de Nolf, W.; Miliani, C.; Dik, J.; Radepont, M.; Hendriks, E.; Geldof, M.; Cotte, M.
	Title	Degradation process of lead chromate in paintings by Vincent van Gogh studied by means of synchrotron X-ray spectromicroscopy and related methods : 2 : original paint layer samples			Type	A1 Journal article
	Year	2011	Publication	Analytical chemistry	Abbreviated Journal	Anal Chem
	Volume	83	Issue	4	Pages	1224-1231
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	The darkening of the original yellow areas painted with the chrome yellow pigment (PbCrO4, PbCrO4·xPbSO4, or PbCrO4·xPbO) is a phenomenon widely observed on several paintings by Vincent van Gogh, such as the famous different versions of Sunflowers. During our previous investigations on artificially aged model samples of lead chromate, we established for the first time that darkening of chrome yellow is caused by reduction of PbCrO4 to Cr2O3·2H2O (viridian green), likely accompanied by the presence of another Cr(III) compound, such as either Cr2(SO4)3·H2O or (CH3CO2)7Cr3(OH)2 [chromium(III) acetate hydroxide]. In the second part of this work, in order to demonstrate that this reduction phenomenon effectively takes place in real paintings, we study original paint samples from two paintings of V. van Gogh. As with the model samples, in view of the thin superficial alteration layers that are present, high lateral resolution spectroscopic methods that make use of synchrotron radiation (SR), such as microscopic X-ray absorption near edge (μ-XANES) and X-ray fluorescence spectrometry (μ-XRF) were employed. Additionally, μ-Raman and mid-FTIR analyses were carried out to completely characterize the samples. On both paint microsamples, the local presence of reduced Cr was demonstrated by means of μ-XANES point measurements. The presence of Cr(III) was revealed in specific areas, in some cases correlated to the presence of Ba(sulfate) and/or to that of aluminum silicate compounds.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000287176900012	Publication Date	2011-02-14
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-2700; 5206-882x	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.32	Times cited	84	Open Access
	Notes	; This research was funded by grants from ESRF (experiment EC-504) and by HASYLAB (experiments 11-20080130 EC and 11-20070157 EC) and was supported by the Interuniversity Attraction Poles Programme-Belgian Science Policy (IUAP VI/16). The text also presents results of GOA “XANES meets ELNES” (Research Fund University of Antwerp, Belgium) and from FWO (Brussels, Belgium) project nos. G.0103.04, G.0689.06, and G.0704.08. The staff of the Van Gogh Museum, Amsterdam, is acknowledged for their agreeable cooperation and for the authorization to publish the images of the paintings in this article. L.M. was financially supported by the Erasmus Placement in the framework of Lifelong Learning Programme (A.Y. 2009-2010). The EU Community's FP7 Research Infrastructures program under the CHARISMA Project (Grant Agreement 228330) is also acknowledged. ;			Approved	Most recent IF: 6.32; 2011 IF: 5.856
	Call Number	UA @ admin @ c:irua:88795			Serial	5571
Permanent link to this record



	Author	Dik, J.; Janssens, K.; van der Snickt, G.; van der Loeff, L.; Rickers, K.; Cotte, M.
	Title	Visualization of a lost painting by Vincent van Gogh using synchrotron radiation based X-ray fluorescence elemental mapping			Type	A1 Journal article
	Year	2008	Publication	Analytical chemistry	Abbreviated Journal	Anal Chem
	Volume	80	Issue	16	Pages	6436-6442
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	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.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000258448100039	Publication Date	2008-07-29
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0003-2700; 5206-882x	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	6.32	Times cited	178	Open Access
	Notes				Approved	Most recent IF: 6.32; 2008 IF: 5.712
	Call Number	UA @ admin @ c:irua:74466			Serial	5906
Permanent link to this record



	Author	Vanmeert, F.; Hendriks, E.; van der Snickt, G.; Monico, L.; Dik, J.; Janssens, K.
	Title	Chemical Mapping by Macroscopic X-ray Powder Diffraction (MA-XRPD) of Van Gogh's Sunflowers : identification of areas with higher degradation risk			Type	A1 Journal article
	Year	2018	Publication	Angewandte Chemie: international edition in English	Abbreviated Journal	Angew Chem Int Edit
	Volume	57	Issue	25	Pages	7418-7422
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	The discoloration rate of chrome yellow (CY), a class of synthetic inorganic pigments (PbCr1-xSxO4) frequently used by Van Gogh and his contemporaries, strongly depends on its sulfate content and on its crystalline structure (either monoclinic or orthorhombic). Macroscopic X-Ray powder diffraction imaging of selected areas on Van Gogh's Sunflowers (Van Gogh Museum, Amsterdam) revealed the presence of two subtypes of CY: the light-fast monoclinic PbCrO4 (LF-CY) and the light-sensitive monoclinic PbCr1-xSxO4 (x approximate to 0.5; LS-CY). The latter was encountered in large parts of the painting (e.g., in the pale-yellow background and the bright-yellow petals, but also in the green stems and flower hearts), thus indicating their higher risk for past or future darkening. Overall, it is present in more than 50% of the CY regions. Preferred orientation of LS-CY allows observation of a significant ordering of the elongated crystallites along the direction of Van Gogh's brush strokes.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000434949200023	Publication Date	2018-03-02
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1433-7851; 0570-0833	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	11.994	Times cited	10	Open Access
	Notes	; The authors acknowledge financial support from BELSPO (Brussels) S2-ART, the NWO (The Hague) Science4Arts “ReVisRembrandt” project, the GOA Project Solarpaint (University of Antwerp Research Council), and the Interreg Smart*Light project. Raman analyses were performed using the European MOLAB platform, which is financially supported by the Horizon 2020 Programme (IPERION CH Grant 654028). The authors thank the staff of the Van Gogh Museum for their collaboration. ;			Approved	Most recent IF: 11.994
	Call Number	UA @ admin @ c:irua:153185			Serial	5517
Permanent link to this record



	Author	Monico, L.; Janssens, K.; Hendriks, E.; Vanmeert, F.; van der Snickt, G.; Cotte, M.; Falkenberg, G.; Brunetti, B.G.; Miliani, C.
	Title	Evidence for degradation of the chrome yellows in Van Gogh's sunflowers : a study using noninvasive in situ methods and synchrotron-radiation-based x-ray techniques			Type	A1 Journal article
	Year	2015	Publication	Angewandte Chemie: international edition in English	Abbreviated Journal	Angew Chem Int Edit
	Volume	54	Issue	47	Pages	13923-13927
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	This paper presents firm evidence for the chemical alteration of chrome yellow pigments in Van Gogh's Sunflowers (Van Gogh Museum, Amsterdam). Noninvasive in situ spectroscopic analysis at several spots on the painting, combined with synchrotron-radiation-based X-ray investigations of two microsamples, revealed the presence of different types of chrome yellow used by Van Gogh, including the lightfast PbCrO4 and the sulfur-rich PbCr1-xSxO4 (x approximate to 0.5) variety that is known for its high propensity to undergo photoinduced reduction. The products of this degradation process, i.e., Cr-III compounds, were found at the interface between the paint and the varnish. Selected locations of the painting with the highest risk of color modification by chemical deterioration of chrome yellow are identified, thus calling for careful monitoring in the future.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000367722500009	Publication Date	2015-10-20
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1433-7851; 0570-0833	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	11.994	Times cited	24	Open Access
	Notes	; We acknowledge financial support from the Italian MIUR project SICH-PRIN (2010329WPF_001) and BELSPO (Brussels) Project S2-ART (SD04A), GOA “SOLARPAINT” (Research Fund Antwerp University, BOF-2015), and FWO (Brussels) projects G.0C12.13, G.0704.08, G.01769.09. We thank ESRF (EC-1051, HG-26) and DESY (I-20120312 EC) for beamtime grants received. Noninvasive analysis of Sunflowers were supported by the EU FP7 programme CHARISMA (Grant 228330) and the Fund Inbev-Baillet Latour (Brussels). L.M. acknowledges financial support from the CNR Short Term Mobility Programme-2013. We thank Muriel Geldof, Luc Megens, Suzan de Groot (The Netherlands Cultural Heritage Agency, RCE), Chiara Grazia, David Buti (CNR-ISTM and SMAArt Centre), and the staff of the Van Gogh Museum for their collaboration. ;			Approved	Most recent IF: 11.994; 2015 IF: 11.261
	Call Number	UA @ admin @ c:irua:131110			Serial	5617
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	Author	van der Snickt, G.; Dubois, H.; Sanyova, J.; Legrand, S.; Coudray, A.; Glaude, C.; Postec, M.; van Espen, P.; Janssens, K.
	Title	Large-area elemental imaging reveals Van Eyck's original paint layers on the Ghent altarpiece (1432), rescoping its conservation treatment			Type	A1 Journal article
	Year	2017	Publication	Angewandte Chemie: international edition in English	Abbreviated Journal	Angew Chem Int Edit
	Volume	56	Issue	17	Pages	4797-4801
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	A combination of large-scale and micro-scale elemental imaging, yielding elemental distribution maps obtained by, respectively non-invasive macroscopic X-ray fluorescence (MA-XRF) and by secondary electron microscopy/energy dispersive X-ray analysis (SEM-EDX) and synchrotron radiation-based micro-XRF (SR m-XRF) imaging was employed to reorient and optimize the conservation strategy of van Eyck's renowned Ghent Altarpiece. By exploiting the penetrative properties of X-rays together with the elemental specificity offered by XRF, it was possible to visualize the original paint layers by van Eyck hidden below the overpainted surface and to simultaneously assess their condition. The distribution of the high-energy Pb-L and Hg-L emission lines revealed the exact location of hidden paint losses, while Fe-K maps demonstrated how and where these lacunae were filled-up using an iron-containing material. The chemical maps nourished the scholarly debate on the overpaint removal with objective, chemical arguments, leading to the decision to remove all skillfully applied overpaints, hitherto interpreted as work by van Eyck. MA-XRF was also employed for monitoring the removal of the overpaint during the treatment phase. To gather complementary information on the in-depth layer build-up, SEM-EDX and SR mu-XRF imaging was used on paint cross sections to record microscale elemental maps.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000398576000019	Publication Date	2017-03-23
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1433-7851; 0570-0833	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	11.994	Times cited	11	Open Access
	Notes	; This research was supported by the Baillet Latour fund, the Belgian Science Policy Office (Projects MO/39/011) and the Gieskes-Strijbis fund. The authors are also indebted to the BOF-GOA SOLAR Paint project of the University of Antwerp Research Council. The church wardens of the cathedral of St. Bavo and their chairman L. Collin are acknowledged for this agreeable collaboration. We also wish to thank conservators L. Depuydt, B. De Volder, F. Rosier, N. Laquiere and G. Steyaert as well as the members of the international committee. We are indebted to Prof. Em. A. Van Grevenstein-Kruse. ;			Approved	Most recent IF: 11.994
	Call Number	UA @ admin @ c:irua:142376			Serial	5688
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	Author	Vanmeert, F.; van der Snickt, G.; Janssens, K.
	Title	Plumbonacrite identified by X-ray powder diffraction tomography as a missing link during degradation of red lead in a Van Gogh painting			Type	A1 Journal article
	Year	2015	Publication	Angewandte Chemie: international edition in English	Abbreviated Journal	Angew Chem Int Edit
	Volume	54	Issue	12	Pages	3607-3610
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	Red lead, a semiconductor pigment used by artists since antiquity, is known to undergo several discoloration phenomena. These transformations are either described as darkening of the pigment caused by the formation of either plattnerite (β-PbO2) or galena (PbS) or as whitening by which red lead is converted into anglesite (PbSO4) or (hydro)cerussite (2 PbCO3⋅Pb(OH)2; PbCO3). X-ray powder diffraction tomography, a powerful analytical method that allows visualization of the internal distribution of different crystalline compounds in complex samples, was used to investigate a microscopic paint sample from a Van Gogh painting. A very rare lead mineral, plumbonacrite (3 PbCO3⋅ Pb(OH)2⋅PbO), was revealed to be present. This is the first reported occurrence of this compound in a painting dating from before the mid 20th century. It constitutes the missing link between on the one hand the photoinduced reduction of red lead and on the other hand (hydro)cerussite, and thus sheds new light on the whitening of red lead.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000351178300008	Publication Date	2015-02-20
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1433-7851; 0570-0833	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	11.994	Times cited	24	Open Access
	Notes	; The authors acknowledge L. Van der Loeff and M. Leeuwestein (Kroller-Muller Museum) for providing the paint sample. We thank Dr. J. Jaroszewicz (WUT) for performing the CT measurements. This research was carried out at the light source PETRA III at DESY, a member of the Helmholtz Association (HGF). We thank Dr. G. Falkenberg and the members of his team for their assistance in using beam line P06. We acknowledge financial support from the University of Antwerp GOA projects “XANES meets EELS” and “SOLARPaint”, as well as from BELSPO (Brussels) Project S2-ART and FWO (Brussels) project “ESRF-Dubble”. ;			Approved	Most recent IF: 11.994; 2015 IF: 11.261
	Call Number	UA @ admin @ c:irua:124620			Serial	5774
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	Author	Janssens, K.; Alfeld, M.; van der Snickt, G.; de Nolf, W.; Vanmeert, F.; Radepont, M.; Monico, L.; et al.
	Title	The use of synchrotron radiation for the characterization of artists' pigments and paintings			Type	A1 Journal article
	Year	2013	Publication	Annual review of analytical chemistry	Abbreviated Journal	Annu Rev Anal Chem
	Volume	6	Issue		Pages	399-425
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	We review methods and recent studies in which macroscopic to (sub)microscopic X-ray beams were used for nondestructive analysis and characterization of pigments, paint microsamples, and/or entire paintings. We discuss the use of portable laboratory- and synchrotron-based instrumentation and describe several variants of X-ray fluorescence (XRF) analysis used for elemental analysis and imaging and combined with X-ray diffraction (XRD) and X-ray absorption spectroscopy (XAS). Macroscopic and microscopic (μ-)XRF variants of this method are suitable for visualizing the elemental distribution of key elements in paint multilayers. Technical innovations such as multielement, large-area XRF detectors have enabled such developments. The use of methods limited to elemental analysis or imaging usually is not sufficient to elucidate the chemical transformations that take place during natural pigment alteration processes. However, synchrotron-based combinations of μ-XRF, μ-XAS, and μ-XRD are suitable for such studies.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000323887500019	Publication Date	2013-06-18
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	1936-1327	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	7.435	Times cited	46	Open Access
	Notes	; ;			Approved	Most recent IF: 7.435; 2013 IF: 7.814
	Call Number	UA @ admin @ c:irua:111315			Serial	5902
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	Author	van der Snickt, G.; de Nolf, W.; Vekemans, B.; Janssens, K.
	Title	μ-XRF/μ-RS vs. SR μ-XRD for pigment identification in illuminated manuscripts			Type	A1 Journal article
	Year	2008	Publication	Applied physics A : materials science & processing	Abbreviated Journal	Appl Phys A-Mater
	Volume	92	Issue	1	Pages	59-68
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	For the non-destructive identification of pigments and colorants in works of art, in archaeological and in forensic materials, a wide range of analytical techniques can be used. Bearing in mind that every method holds particular limitations, two complementary spectroscopic techniques, namely confocal ì-Raman spectroscopy (ì-RS) and ì-X-ray fluorescence spectroscopy (ì-XRF), were joined in one instrument. The combined ì-XRF and ì-RS device, called PRAXIS unites both complementary techniques in one mobile setup, which allows ì- and in situ analysis. ì-XRF allows one to collect elemental and spatially-resolved information in a non-destructive way on major and minor constituents of a variety of materials. However, the main disadvantages of ì-XRF are the penetration depth of the X-rays and the fact that only elements and not specific molecular combinations of elements can be detected. As a result ì-XRF is often not specific enough to identify the pigments within complex mixtures. Confocal Raman microscopy (ì-RS) can offer a surplus as molecular information can be obtained from single pigment grains. However, in some cases the presence of a strong fluorescence background limits the applicability. In this paper, the concrete analytical possibilities of the combined PRAXIS device are evaluated by comparing the results on an illuminated sheet of parchment with the analytical information supplied by synchrotron radiation ì-X-ray diffraction (SR ì-XRD), a highly specific technique.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000256426000008	Publication Date	2008-03-19
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0947-8396	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	1.455	Times cited	56	Open Access
	Notes				Approved	Most recent IF: 1.455; 2008 IF: 1.884
	Call Number	UA @ admin @ c:irua:74465			Serial	5695
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	Author	Trentelman, K.; Janssens, K.; van der Snickt, G.; Szafran, Y.; Woollett, A.T.; Dik, J.
	Title	Rembrandt's An Old Man in Military Costume: the underlying image re-examined			Type	A1 Journal article
	Year	2015	Publication	Applied physics A : materials science & processing	Abbreviated Journal	Appl Phys A-Mater
	Volume	121	Issue	3	Pages	801-811
	Keywords	A1 Journal article; AXES (Antwerp X-ray Analysis, Electrochemistry and Speciation)
	Abstract	The painting An Old Man in Military Costume in the J. Paul Getty Museum, by Rembrandt Harmensz van Rijn, was studied using two complementary, element-specific imaging techniques-neutron activation autoradiography (NAAR) and macro-X-ray fluorescence (MA-XRF) mapping-to reveal the second, hidden painting. NAAR provided a strong image of the face and cloak of the underlying figure, along with an indication of the chemical composition. The single-element distribution maps produced by MA-XRF mapping provided additional details into the shape of the underlying image and the composition of the pigments used. The underlying figure's face is richer in mercury, indicative of the pigment vermilion, than the face of the figure on the surface. Likewise, the cloak of the underlying figure is richer in copper than the surface figure though the identity of the copper-containing pigment cannot be determined from these data. The use of iron earth pigments, specifically Si-rich umbers, is indicated through the complementary information provided by the NAAR and MA-XRF maps. These data are used to create a false color digital reconstruction, yielding the most detailed representation of the underlying painting to date.
	Address
	Corporate Author				Thesis
	Publisher		Place of Publication		Editor
	Language		Wos	000364914100003	Publication Date	2015-08-31
	Series Editor		Series Title		Abbreviated Series Title
	Series Volume		Series Issue		Edition
	ISSN	0947-8396	ISBN		Additional Links	UA library record; WoS full record; WoS citing articles
	Impact Factor	1.455	Times cited	22	Open Access
	Notes	; The authors gratefully acknowledge the assistance of all those who aided in the examination of this painting over the decades, that has culminated in the work presented here. Particular thanks go to Mark Leonard (former head of Paintings Conservation at the J. Paul Getty Museum) and Henry Prask (NIST) for carrying out the NAAR analysis; John Twilley (former GCI Scientist) for early investigations; Andrea Sartorius (former JPGM Paintings intern) for creating a mock-up painting used in earlier phases of this work; Peter Reishig (former GCI intern) for compiling the NAAR data; Catherine Patterson, Lynn Lee, and David Carson (GCI Science) and Gene Karraker (JPGM Paintings Conservation) for helping with the setup and operation of the M6 Jetstream; and Giacomo Chiari (former head of GCI Science) for performing the XRD analysis. Koen Janssens and Geert van der Snickt acknowledge the Fund Inbev-Baillet Latour for financial support. Joris Dik acknowledges the help of the Netherlands Organization for Scientific Research (NWO) in the form of a VIDI grant in the Innovational Research Incentive Scheme. ;			Approved	Most recent IF: 1.455; 2015 IF: 1.704
	Call Number	UA @ admin @ c:irua:130289			Serial	5812
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