The Science of Van Gogh's Bedrooms

It’s interesting that when people come to the Art Institute, they’re looking at The Bedroom and they think “Oh, I’ve seen this before,” without realizing that there are three versions, and they look very similar but there are a lot of differences And what makes this project so exciting is that now we included the conservators and scientists at Amsterdam and in Paris, and so that we’re really working collaboratively to find what makes one different. I’m a scientist here at the Art Institute, and as a scientist in the museum I use cutting edge scientific tools to understand the materials, understand how they may have changed over time, and help to answer many of the questions that The Bedroom has posed us through the years. We go from tools that are very simple but very important, our eyes, to high-powered microscopes, to tools that use x-rays, infrareds, ultraviolet light to penetrate below the surface of the works and to discover things that our eyes cannot see. I'm the research microscope in the conservation department. Going back into the seventies when we first took tiny little samples, scraping samples, we mounted them on slides and then we compared them to what pigments we have in our reference collection and we determined, you know what the palate was. We analyze the ground material, we looked at the paint we looked at the painting technique, all of those things. With raking light, we use an intense source of white light placed at a very sharp angle, close to the surface and that highlights the texture very effectively and it's really exciting because you can almost feel Van Gogh's gesture in applying the paint. In Chicago, the brush strokes are much more pronounced and expressive with a style of painting that has been described as graphic due to its more linear quality and in Amsterdam the application is more flat and Vincent says like a Japanese print. In our work we use x-rays to examine paintings the same way as we examine bodies–to reveal the inner structure. In the case of the Amsterdam version there are elements in the build-up of the paint that highlight how the wall paint was applied first and then, for example, the pictures that we see on the wall where applied. When we look at the Chicago painting we can see in that same area of the wall, there are some darker squares. In this case the artist had already an idea of where those pictures would be. He leaves the space for the paintings to be painted. As technology evolves there are more things that we can see and that we can discover. And there are definitely tools now that allow, for example, in one single sweep to reconstruct the palette That Van Gogh used that we didn't have five years ago. Using x-rays to read the chemical composition of the paint, and what this allows us to do is to really compare the different mixtures that Van Gigh used, for example, to depict the green in the Amsterdam version as opposed to the Chicago version. Really until twenty years ago the chronology and which one came first and which one came second that was still in question and art historians and conservators were still trying to figure out is the Amsterdam or the Chicago one the first? In his letters he talks about making a smaller repetition for his mother and sister and the Paris version is the smaller size, so we can know for sure that that was the version that was intended. We go to the letters as almost like a witness, first witness account, of what happened and Van Gogh describes damage that occurred while the first version was in the studio. So then we look carefully at the surface of the painting a little bit like a lunar landscape and looking for those craters that would be an evidence of the fact that with humidity, the canvas is going to expand and contract in different ways and the hard paint on top. And so what happens is the paint can flake and can expose bare canvas. On the Chicago painting it's evident that the flaking didn't of course down to the canvas. That is more likely another type of damage that Van Gogh also describe where he says "I paint very quickly and the solvent evaporates quickly and I have problems of adhesion of the different layers." We use the evidence and the different types of damages that are described, and our observations of the physical manifestation of the damage to determine which one came first. And our observations confirm that the Amsterdam version is indeed the first one that was painted. What we were able to discover is a definitive understanding of the color and the color change. So we removed a small sample from the walls and mounted as a cross section, which is basically like a layer cake, exposing layers from the preparation of the canvas up to the top. While the top of that wall paint was light blue, inside the layer there were many particles of bright pink pigment, and, of course, pink and blue makes purple. Even if it’s microscopic, you can see it with your naked eyes, it’s bigger than one pigment particle, and it was really the eureka moment, like now we know what was was the color that Van Gogh intended. We have today scientific techniques to identify if there are pigments that have almost disappeared. Even if there is just one remaining particle we can find it like a needle in a haystack, and the pigment was carmine lake. Van Gogh was well aware that color changed, in fact he said that “paintings fade like flowers,” but he was very attracted by these bright pinks and purples, and so he uses them thinking that if he paints them boldly, time will tone them down. So the knowledge of identifying this pink pigment as carmine lake was the beginning of a journey in search of developing and refining our understanding of how we can visualize this effect from a microscopic sample to the entire surface of the wall. But now we had to enlist many colleagues to come up with very complex algorithm and create as accurate as possible a visualization of what the painting might have looked like with digital means. And this, of course, is a suggestion, but it’s a powerful suggestion. Even if it’s an iconic image that we all recognize, we can still discover so many new things.