Foto Marc Bolsius

Omvangrijkste onderzoeksproject naar Jheronimus Bosch ooit werpt nieuw licht op zijn œuvre

1 februari 2016

Valuable discoveries and a much greater understanding of Hieronymus Bosch’s work are the key achievements of years of systematic research and technological innovation by the Bosch Research and Conservation Project. In this way, the BRCP has made an important contribution to our understanding of the creativity and genius of this son of ’s-Hertogenbosch (Den Bosch). The BRCP’s findings have, moreover, expanded Bosch’s relatively small known oeuvre. Meanwhile, a substantial number of his paintings and drawings have been restored in the run-up to the celebration of 500 years of Hieronymus Bosch, giving them back their original lustre and reflecting the project’s twin focus on conservation as well as research. The BRCP is an initiative of Radboud University Nijmegen, the Hieronymus Bosch 500 Foundation and Het Noordbrabants Museum. It came about with the financial support of the Gieskes-Strijbis Fund and the Getty Foundation (Panel Paintings Initiative).

Bosch Research and Conservation Project (BRCP)

The Bosch Research and Conservation Project (BRCP) is the largest international art-historical initiative ever undertaken into the paintings and drawings of Hieronymus Bosch (c. 1450–Den Bosch 1516). A team of nine experts specialising in different fields has intensively and systematically examined Bosch’s entire oeuvre worldwide since 2010.


Virtually the whole of Bosch’s oeuvre has been documented using a standardised, scientific research procedure. Bosch research has traditionally tended to focus on the meaning of the painter’s artworks, with questions such as painting technique, workshop practice and the condition of the works receiving far less attention. Detailed analysis is, however, crucial to understanding the meaning of these frequently enigmatic images. The BRCP’s first concern, therefore, was to establish a painstaking, standardised body of documentation for the paintings. This was achieved using infrared reflectography and ultra-high resolution digital macrophotography, in both infrared and visible light.

Principal discoveries

Using the advanced digital infrastructure developed by the BRCP, it was possible to identify hitherto unnoticed connections. The distinctive way in which Bosch often ‘drew’ details in paint and modelled in impasto can now be visualised effortlessly and compared directly and precisely across all the paintings. A connection has also been made for the first time between the paintings and drawings – worlds that had largely remained separate. It was found that the way Bosch painted shows significant similarities with the way he drew. In addition to providing a much better insight into the genesis of the artworks, the BRCP documentation has played an important role in the attribution of works that had not previously been ascribed to Bosch himself. The most surprising outcome of the research, however, is the attribution to Bosch of the relatively unknown painting the Temptation of St. Anthony from the Nelson-Atkins Museum (Kansas City, Missouri), where it had been held in storage (see separate press release). All these works can be seen at the exhibition in Den Bosch.

The number of drawings attributed to the master has almost doubled. The BRCP team was able, for instance, to identify the hitherto anonymous drawing Infernal Landscape as an authentic work by Hieronymus Bosch. Up to now, the drawing had been hidden away in private ownership and will be shown in public for the first time during the large-scale Hieronymus Bosch exhibition opening on 13 February 2016 at Het Noordbrabants Museum. The painting of the Last Judgement from Bruges has also been attributed once and for all to Bosch by the BRCP; the cleaning and restoration of the grisailles on the exterior of the wings have brought out the immense painterly quality of this work once more and have revealed the same artist’s hand that we find in the Haywain and St. John on Patmos.

Composition of the BRCP team

The international BRCP team consists of nine researchers, each specialising in a particular field. They include art historians (both technical and theoretical), a photographer, a restorer and a computer expert (see list for more details). The photographer, for instance, used a standard approach and equipment to document the paintings and drawings at unprecedentedly high resolution. This was done not only in visible light, but also using infrared photography, infrared reflectography and digital X-radiography. Not only were the smallest details made visible this way, so too were the preparatory underdrawings, normally concealed beneath the various layers of paint and invisible to the naked eye. Dozens, and in some cases hundreds, of 60-megapixel photographs were taken of each painting. A restorer then analysed each of Bosch’s paintings according to a fixed protocol in order to learn more about the techniques used to create them and about the current condition of these five-hundred-year-old paintings.

Spectacular restorations

In addition to research, the BRCP’s mission has been to focus on the conservation and restoration of Bosch’s paintings. Meticulous study of the condition of the panels revealed that many of the works were in need of care. This prompted the restoration of a substantial proportion of the oeuvre, thanks to subsidies from the BRCP and the Getty Foundation (Panel Paintings Initiative). The result is a series of spectacular restorations, including that of the Wilgefortis Triptych, the Hermit Saints Triptych and the Visions of the Afterlife from Venice, St. Jerome from Ghent, St. Christopher from Rotterdam and the Last Judgement from Bruges. Restoration uncovered a number of concealed features. ‘We’re now seeing the real Bosch, which means we can interpret and evaluate his paintings better than in the past’, says Luuk Hoogstede, who worked on the project as a restorer.

Innovative website

The information assembled by the BRCP has been made accessible to all via the website The master’s work can be viewed and compared there down to the smallest details using the groundbreaking ‘curtain viewers’ developed by the computer scientist Robert G. Erdmann. These offer visitors to the site an accessible way to process and compare the large amount of data assembled using the new imaging and photographic techniques. Each type of photograph is overlaid in a series of ‘curtains’ that can be drawn back to allow the user to concentrate on a single detail without losing sight of the context. The website makes it possible to journey through each layer of a particular painting.

‘This is the first time the entire oeuvre of a single artist has been visually documented using the same standards’, says Erdmann, who is attached to the Rijksmuseum in Amsterdam, and has also worked for institutions like MoMA and the Metropolitan Museum of Art in New York. ‘Each museum normally uses its own cameras, with different lighting and formats, which makes it hard for researchers to compare artworks properly. In scientific terms, standardising the research process represents a significant advance, as we can now be sure that it is the paintings and drawings we are comparing with one another, and not just the way they have been photographed.’

Erdmann developed another compelling new application for the BRCP, based on the ‘Morelli method’, which takes its name from the nineteenth-century Italian art historian Giovanni Morelli (1816–1891), who devised a method for determining the authenticity of an artwork based on comparison of painted details such as ears and hands. It is in small details like this, after all, that the artist’s ‘signature’ can be found. Erdmann modernised Morelli’s ideas for the Bosch project. When a series of ears from different works by Bosch are viewed side by side on a computer screen, the similarities and differences are immediately apparent. All the BRCP’s photographic documentation is available online at


All archive sources on Hieronymus Bosch, his immediate context and his work have been made available, together with translations and notes, on the BoschDoc website – a collaborative project with Huygens ING, Den Bosch Municipal Archive and Radboud University Nijmegen. BoschDoc can be accessed via

Scholarly publications by the BRCP

The results of the BRCP’s international research have been published in a monograph comprising a two-volume scholarly reference work totalling over 1,000 pages and with an unprecedented range of illustrations. Volume 1, the Catalogue raisonné, deals with all drawings and paintings by Bosch and his workshop, accompanied by discussions of several paintings until recently considered to be autograph. The Catalogue raisonné is introduced by four essays exploring Bosch’s life and career, the question ‘what is a Bosch?’, the materials and techniques he used and the conservation and restoration history of his works. Volume 2, Technical Studies, contains all the research reports on the examined paintings, introduced by two essays on the photography and image-processing performed by the BRCP.

The BRCP team

Dr Matthijs Ilsink (art historian, BRCP coordinator, Radboud University Nijmegen)
Matthijs Ilsink graduated in the History of Art at Radboud University Nijmegen with a thesis on Roman Baroque drawings (1999). At Nijmegen he also received his Ph.D. (2009, cum laude) for a study on the selfreflexivity of works by Jheronimus Bosch and Pieter Bruegel: Bosch en Bruegel als Bosch. Kunst over kunst bij Pieter Bruegel (ca. 1528-1569) en Jheronimus Bosch (c. 1450-1516) [Bosch and Bruegel as Bosch. Art about art in the work of Pieter Bruegel the Elder (c. 1528-1569) and Jheronimus Bosch (c. 1450-1516)]. He worked as an assistant-curator on two international loan exhibitions at Museum Boijmans Van Beuningen in Rotterdam: Jheronimus Bosch and Pieter Bruegel the Elder: Master Draftsman (both 2001). At the moment Matthijs Ilsink is responsible for the coordination of the Jheronimus Bosch Research & Conservation Project, an international scientific research project that will lead to the commemoration of the death of Bosch 500 years ago in 2016. He also teaches at Nijmegen University.
Prof. Jos Koldeweij (art historian, chair of the BRCP scholarly committee, Radboud University Nijmegen)
Jos Koldeweij has been Professor of Medieval Art History at Radboud University Nijmegen since 1993. He previously worked as a lecturer and researcher at the Universities of Utrecht and Nijmegen, and as conservator at Het Noordbrabants Museum in ’s-Hertogenbosch. Koldeweij studied art history in Utrecht, where he graduated cum laude in 1985 with a thesis on medieval image-formation around the figure of St Servatius. He focuses in particular on the visual arts in the late Middle Ages in a cultural-historical context, with the emphasis on North-West Europe. Koldeweij has curated exhibitions including ‘Hieronymus Bosch’ (Museum Boijmans Van Beuningen, Rotterdam 2001, with two-volume scholarly catalogue) and ‘Geloof & Geluk. Sieraad en devotie in middeleeuws Vlaanderen’ (Gruuthuse Museum, Bruges 2006–07, with scholarly catalogue). The work of Hieronymus Bosch is a key theme in his present research. This has been reflected to date in the foundation and supervision of the Jheronimus Bosch Art Center in ’s-Hertogenbosch and a series of international conferences on Bosch (2001, 2007, 2012 and 2016), as well as the Bosch Research and Conservation Project, culminating in the commemoration of the five-hundredth anniversary of the painter’s death (1516–2016). Jos Koldeweij is the initiator and academic head of the Bosch Research and Conservation Project and, in collaboration with Dr Matthijs Ilsink, guest curator of the exhibition Hieronymus Bosch – Visions of a Genius at Het Noordbrabants Museum in the early part of 2016 (with accompanying catalogue).
Prof. Ron Spronk (technical art historian, Queen’s University, Kingston, Ontario, Radboud University Nijmegen)
Ron Spronk has been Professor of Art History at Queen’s University in Kingston, Ontario, since 2007. He has also been Hieronymus Bosch Special Chair at Radboud University Nijmegen since 2010. He worked at Harvard Art Museum in Cambridge, Massachusetts, from 1994 to 2007, as an art-historical researcher attached to the Straus Center for Conservation and Technical Studies. Spronk is a technical art historian with a special interest in painting materials and techniques. He studies the genesis and condition of easel paintings with techniques such as infrared reflectography and X-radiography. Spronk has worked on a number of major interdisciplinary research and exhibition projects, all of which entailed close collaboration with art historians, restorers, chemists and other scholars. Alongside his work for the BRCP, he is also actively involved in the restoration of the Ghent Altarpiece, for which he coordinated the on-line research tool Closer to Van Eyck, and an exhibition on Pieter Bruegel in Vienna (2018).
Luuk Hoogstede, MA (painting restorer, Stichting Restauratie Atelier Limburg (SRAL))
Luuk Hoogstede is Paintings Conservator at the Stichting Restauratie Atelier Limburg (SRAL) in Maastricht and member of the multidisciplinary BRCP Research Team. Hoogstede graduated cum-laude in Art History and is trained in Paintings Conservation, gaining experience at both the Van Gogh Museum and Rijksmuseum in Amsterdam. In 2009, he was granted a Fellowship at the New York Metropolitan Museum of Art, to research and practice techniques used in the structural conservation of panel paintings. As both Art historian and Conservator, for the BRCP Hoogstede investigates the painting technique, Bosch’s use of materials and assesses the condition of the panels. He is also responsible for compiling the technical reports on the examined paintings and advises on conservation needs. Hoogstede co-restored the Venetian Bosch paintings (2013-16) and has had an advisory role in treatments of several other works by Jheronimus Bosch. He specializes in the conservation of panel paintings and is participant of the Getty Foundation’s Panel Paintings Initiative. In 2013, Hoogstede was awarded a grant from the Gieskes Strijbis Foundation to have his Bosch research and conservation work result in a Ph.D.-thesis.
Prof. Robert G. Erdmann (computer scientist, Rijksmuseum, University of Amsterdam, Radboud University Nijmegen)
Prior to earning his Ph.D. from the University of Arizona in 2006, Robert Erdmann started a science and engineering software company and worked extensively on computational materials science while working at Sandia National Laboratories. He subsequently joined the faculty at the University of Arizona in the Program in Applied Mathematics and the Department of Materials Science and Engineering as Assistant Professor and then Associate Professor, where he worked on multiscale material process modelling and image processing and data fusion for cultural heritage. In 2013, he was a Fellow in Residence at the Netherlands Institute for Advanced Study, and in 2014 he moved permanently to Amsterdam to focus full-time on combining materials science and computer science to help the world access, understand, and preserve its cultural heritage. He is currently Senior Scientist at the Rijksmuseum, and he holds the Rijksmuseum Chair in Conservation Science as a Professor at the University of Amsterdam and the Special Chair for the Visualization of Art History at Radboud University. He is the director of the Thread Counting Automation Project (TCAP) and is responsible for digital infrastructure for the Bosch Research and Conservation Project (BRCP), where he developed a variety of image-processing and visualization techniques for the project (
Rik Klein Gotink (photographer)
Rik Klein Gotink has been a freelance cultural heritage photographer since 1993 for a variety of museums, including the Rijksmuseum Kröller-Müller, the Rijksmuseum Twenthe, the Gemeentemuseum in The Hague, the Stedelijk Museum Amsterdam, De Lakenhal in Leiden, the Koninklijk Museum voor Schone Kunsten in Antwerp, Museum Boijmans van Beuningen in Rotterdam and Kasteel Twickel in Delden. He also works part-time for the Rijksmuseum in Amsterdam as part of a team of eight photographers. He provides photography training and guest lessons for restorers for the University of Amsterdam, Queen’s University, Kingston, Ontario and the Kunsthistorisches Museum in Vienna, among others. His own training consisted of a two-year foundation course in Technical Physics at the University of Twente, and study at the AKI (now ARTEZ) art academy in Enschede. (
Hanneke Nap, MA (research assistant)
Hanneke Nap studied art history at Radboud University Nijmegen, where she was awarded her Master’s in 2011. She specialised during her studies in late-medieval painting. Having completed her internship at the Bosch Research and Conservation Project, she has been employed as a research assistant at the BRCP since 2012. As such, she has been involved in all the different aspects of the project.
Daan Veldhuizen, MA (research assistant)
Daan Veldhuizen has worked as a research assistant for the BRCP since the summer of 2014. He graduated cum laude in art history at Radboud University Nijmegen in February 2015. His master’s thesis was on seventeenth-century propaganda prints featuring Maurice of Nassau.
Travis Sawyer, BSc. (research assistant to Robert G. Erdmann)
Loes Scholten
Loes Scholten followed her art school training with the transfer programme and Master of Art History course at Radboud University Nijmegen. She took the opportunity during her Master’s studies to focus on the work of Hieronymus Bosch and graduated with a thesis on the iconography and attribution of drawings associated with Hieronymus Bosch. Having received her Master’s, she remained at Radboud University Nijmegen where she carried out archive research into Bosch’s family and work situation, resulting in an article on Bosch’s relationship with the Van Aken family workshop. Loes Scholten is currently working for the Bosch Research and Conservation Project on the compilation of the BoschDoc database, which will store all the available archive material on Bosch, his work, and his living and working situation.

See also:

Bosch Research and Conservation Project

Press File including Images