CODART, Dutch and Flemish art in museums worldwide

Research Group Reveals to the Eye Overpainted Portrait beneath Van Gogh Landscape

The Universities of Delft and Antwerp, working with the European Synchrotron Radiation Facility in Hamburg and the Kröller-Müller Museum in Otterlo, have announced spectacular results in making an overpainted head beneath a van Gogh landscape in the Kröller-Müller Museum visible to the eye.


PRESS RELEASE – Persbericht in het Nederlands
Looking through Van Gogh
Advanced X-ray analysis reveals a portrait below the painting of a landscape
A new technique allows pictures which were later painted over to be revealed once more in unprecedented detail.
An international research team, including members from the Technical University of Delft (NL) and the University of Antwerp (B) has successfully applied this technique for the first time to the painting entitled Grasgrond (Patch of grass) by Vincent van Gogh.
Behind this painting is the portrait of a woman.


It is well-known that Vincent van Gogh often painted over his older works. Experts estimate that about thirty percent of his paintings conceal other compositions under them. A new technique, based on synchrotron radiation induced X-ray fluorescence spectroscopy, reveals this type of hidden painting.

The techniques usually employed to reveal concealed layers of paintings, such as conventional X-ray radiography and Infra-red reflectography, have their limitations. Together with experts from the Deutsches Elektronen-Synchrotron in Hamburg and the Kröller-Müller Museum, TU Delft materials expert and art historian Dr Joris Dik and University of Antwerp chemistry professor Koen Janssens therefore chose to adopt a different approach. The painting is subjected to an X-ray beam from a synchrotron radiation source, and the fluorescence of the layers of paint is measured. This technique has the major advantage that the measured fluorescence is specific to each chemical element. Each type of atom (e.g. lead or mercury) and also individual paint pigments can therefore be charted individually. The benefit of using synchrotron radiation of high energy is that it is strongly penetrating so that element specific analysis well below the visible surface becomes possible. The upper layers of paint distort the measurements only to a small degree. Moreover, the speed of measurement is high, which allows relatively large areas to be visualised.

Patch of Grass

This method was applied to a painting by Vincent van Gogh. The work in question, Grasgrond, was painted by Van Gogh in Paris in 1887 and is owned by the Kröller-Müller Museum (Otterlo, The Netherlands). Previous research had already discovered the vague outline of a head behind the painting. It was scanned at the synchrotron radiation source DORIS at Deutsches Elektronen-Synchrotron DESY in Hamburg using an intense but small X-ray beam. Over the course of two days, the area covering the image of a woman’s head was scanned, measuring 17.5 x 17.5 cm.

The measurements enabled researchers to reconstruct the concealed painting in unparalleled detail. In particular the combination of the distribution of the elements mercury and antimony (from specific paint pigments) provided a ‘colour photo’ of the portrait which had been painted over.
The reconstruction enables art historians to understand the evolution of Van Gogh’s work better. The applied technique is expected to pave the way for research into many other concealed paintings.

Additional investigations performed at the European Synchrotron Radiation Facility (ESRF, Grenoble) revealed the presence of the pigments Naples’ Yellow (lead antimonate, yellow-brown) and Vermillion (mercury sulphide, red), employed by Van Gogh to paint the portrait.



Under embargo until 30 July 2008    
3 min. presentation by art historian Joris Dik summarizing the examination results (low resolution Quicktime movie)
Click here to download (.MOV)

(10 MB,
600 x 450 pixels/frame)




© TU Delft, NL

3 min. presentation by art historian Joris Dik summarizing the examination results (high resolution Quicktime movie)
Click here to download (.MOV)

(140 MB,
1200 x 900 pixels/frame)




© TU Delft, NL

Reprint of Analytical Chemistry paper dd. 29 July 2008,
doi 10.1021/ac800965g

Click here to download (.PDF)

(3 MB)
Published electronically on 30 July 2008, in print on 15 August 2008 by the American Chemical Society.

High resolution photograph of Patch of Grass

Click here to download (.JPG)

(2 MB, 1642 × 1280 pixels)

source: Wikipedia
© Kröller-Müller Museum, NL

Analytical chemist Koen Janssens (B) adjusting the alignment of the painting in the X-ray fluorescence spectrometer at beamline L of the DORIS synchrotron facility, Hamburg

Click here to dow
nload (.JPG)
(6 MB, 4256 x 2832 pixels)
Click here to download (.AVI)
(61 MB, 720 x 576 pixels/frame)




© DESY Hamburg, D

© DESY Hamburg, D

Conservators Luuk Van der Loeff (NL, left) and Geert Van der Snickt (B) discussing the results
Click here to download (.JPG)

(5 MB, 4256 x 2832 pixels)




© DESY Hamburg, D

Happy faces at the end of a succesful experiment at the Hamburg synchrotron
Left to right: Koen Janssens (B), Joris Dik (NL), Rinus van Beek (NL), Luuk Van der Loeff (NL), Karin Rickers (D), Geert Van der Snickt (B)

Click here to download (.JPG)
(6 MB, (4256 x 2832 pixels)




© DESY Hamburg, D




Conservation scientist Marine Cotte (F) at work in the control hutch of ESRF beamline ID21

Click here to download (.JPG)
(0.5 MB, 2409 x 1807pixels)




© ESRF Grenoble, F







Painting conservator Luuk van der Loeff (NL) removing the painting from the scanning stage at the end of the experiment.

Click here to download (.AVI)

(72 MB, 720 x 576 pixels)

Click here to download (.AVI)

(63 MB, 720 x 576 pixels)




© DESY Hamburg, D




© DESY Hamburg, D







Is it a landscape ? It’s also a portrait !

Click here to download (.JPG)

(0.7 MB, 903 x 1160 pixels)







© DESY Hamburg, D


Press release by TU Delft, NL
Press release by DESY, Hamburg, D including additional images

Contact information

  Office phone Mobile phone
Dr. Joris Dik, Technical University of Delft (NL) +31 152 789 571 +31 624 806 855
Prof. Koen Janssens, University of Antwerp (B) +32 3 820 2373 +32 474 465 532
Geert Van der Snickt, University of Antwerp (B) +32 3 820 2363 +32 494 624 473
Luuk Van der Loeff, Kröller-Müller Museum (NL) +31 318 596 158 +31 612 509 778
Dr. Karin Rickers, Hamburger Synchrotron Radiation Laboratory (D) +49 408 998 2930  
Dr. Marine Cotte, European Synchrotron Radiation Facility (F) +33 476 882 127