Hieronymus Bosch's paintings and drawings feature the most startling creatures. Thanks to the latest techniques, you can even look under the top layer of paint:to discover an equally fascinating, hidden world there. Kennislink visited the new exhibition of the famous painter in Den Bosch.
A devil on skates, flying fish and a funnel man. The most wonderful creatures are in the paintings of Hieronymus Bosch, also known as Hieronymus Bosch. But those are far from all the remarkable creatures he made. Thanks to new technology, art historians have discovered that under the top layer of paint is still a wonderful world. “This allows us to look over Bosch's shoulder,” says art historian Matthijs Ilsink of Radboud University. He is one of the compilers of the exhibition Jheronimus Bosch – Visions of a Genius in the Noordbrabants Museum.
Plant
Take Bosch's painting of John the Baptist. Cloaked in a red cloak, Johannes lies lost in thought. He points to a sheep (here no doubt meant as the Lamb of God). Monkeys climb trees, birds fly by. But the biggest eye-catcher is a fantastic plant. Bulbs full of seeds grow from the branches that birds peck out.
It gets even crazier when we look behind this visible layer of paint. Robert Erdmann, researcher at the Rijksmuseum and professor at the University of Amsterdam and Radboud University, pushes a button. Suddenly an infrared photo of the painting can be seen. A kneeling man with a hat appears behind the plant.
“Probably this man was the client,” says Erdmann in the Noordbrabants Museum. “Maybe the man didn't pay and that's why Bosch turned him into a plant.”
Handwriting of Bosch
Infrared photography looks at light with a different, longer wavelength than visible light. “This allows us to see what is under the outer layer of paint. In this way we expose the secrets of a painting”, explains Erdmann.
As long as there is carbon in the material with which Bosch made the signature, it can be seen, adds Jos Koldeweij (Radboud University) professor of art history. “Bosch often sketched with chalk and we make that largely visible with infrared. In addition, he used a thin watery paint or ink. Because we take the photos in such a high resolution, we can even see where he put down and lifted his brush. Because that will be a small drop. It is almost Bosch's handwriting.”
Revelations
Technique also takes a new look at one of Bosch's most beautiful paintings:Death and the Miser. An old man, very emaciated, is dying. Death (The Grim Reaper) opens the door and comes for him. Meanwhile, a devil tries to give him a bag of money. An angel points the miser to Jesus on the cross. Does the man choose the redemption of Christ or does he cling to the earthly money?
Erdmann shows the signature, which exposed infrared photography. Now the miser himself holds the bag of money. In his other sand is a richly decorated goblet. Now it looks like he wants to bribe death so he can live longer. “The same painting, but a completely different story,” says Erdmann.
These kinds of revelations are possible thanks to technology, which is why science is so eager to take advantage of them. The findings are not only available to researchers, but also to the general public. The Bosch Research and Conservation Project that applied the different techniques will soon publish all images on boschproject.org. So that visitors can easily sign Death and the miser can see. Erdmann made a very user-friendly curtain viewer especially for this purpose :a way to view the different versions of a painting (see image Triptych of the crucified martyr for a detailed explanation).
Frankenstein
All images of the paintings are made in very high resolution. To do this, the scientists took a lot of photos of parts of a painting or drawing. As a result, even the smallest detail is visible. “But it was difficult to put all those photos together again, so that you see a painting again,” says Erdmann. “It's a big puzzle. Compare it to a panoramic photo that you take yourself of a blue sky and grass. If you want to stitch a lot of photos together, it looks crazy. For example, the light falls slightly differently with each photo. In addition, the detail photos partly overlap and this must fit nicely. Is it not quite right or is the light just different? We immediately notice that, it has to do with the way people look.”
So the scientists couldn't get away with just cutting and pasting. Erdmann therefore created an algorithm through which the computer stitches the images together. Simply put, this calculation program classifies different parts of the painting according to the amount of detail. The sky contains largely the same color and that is why, for example, pieces of a thousand pixels merge into each other. But with small details, such as an owl in a tree, this happens at the level of only a few pixels. “It's like putting together Frankenstein's monster, but with a painting,” says Erdmann. “And if all those different parts merge neatly into each other, then you have the painting digitally in a particularly high resolution.”
And that has already paid off. These images allow art historians to compare details of the paintings. “This allows us to check even more closely whether we are seeing a real Bosch or an imitation,” says Ilsink. As an example he mentions comparing hands or ears. “Because of the extremely high resolution images, I can see them clearly next to each other on the computer. I used to have to print out images of much lower quality and put them on a table.”
Dragons
With the push of a button, Erdmann, for example, puts all hands together that Bosch painted. It is immediately noticeable that not all hands look alike. Erdmann clicks on eight hands, which look clearly different from the other hands that Bosch painted. “By selecting them, you can see where those hands come from,” he says. Christ Carrying the Cross appears on the screen. “All eight deviant hands are from this painting. Partly because of this, we suspect that this is not a real Bosch," says Erdmann.
Ilsink emphasizes how valuable this technique is. “We have never been able to look at his paintings in such detail before and that is what makes it so special.” It is a new litmus test for Bosch's work. And that can also be very beneficial. Thus, by looking at the details in the same way, the drawing Helllandscape recognized as a true Bosch. The magazine is in a private collection in Belgium.
Erdmann zooms in on details of the drawing. Like a barrel, which is just as drawn as on Bosch's paintings. Also a bell, a figure roasted like a pig on a spit and the dragons are much the same. “It's great that this method allows us to recognize this work as a Bosch. That is a great discovery,” says Erdmann.