Lecture: Rembrandt: Narrator: Listen to part of a lecture in an Art History class. Professor: We were talking last time about indirect influences some painters had on those of later eras. Let's focus for a moment on a painter who was famous not just for his paintings, but for influence – his direct influence on other painters during his own time. I'm talking about Rembrandt. Rembrandt taught just about every significant painter of his era. We're talking the 1600s in the Netherlands. He was so influential, that there have been lingering questions about the authenticity of some of the paintings attributed to him. I mean, he ran a workshop where he actively encouraged his pupils to imitate his style, even collaborated with them. And so, since the late 1960s, there have been serious efforts to examine his paintings, in an effort to prove it was indeed Rembrandt himself who painted them. Well. What happened was, the interesting results of these investigations had to do with, not so much authentication, but what the results revealed about Rembrandt's methods, his procedures. Now one aspect of these paintings that the investigators focused on was, the lower layers of paint; the first layers that were applied to the canvas or wood panel. You have a couple of ways of seeing under the surface. The older technique is simple: X-radiography. X-radiography is the same technique a doctor uses to take a picture of your bones, but if you x-ray a painting, well, you can see the lower layers all right, but only the lighter areas. The dark areas don't show up. But, there is another technique that does reveal the darker shade. It's a little more complicated. It's called autoradiography. This technique involves exposing the painting to mild radiation. Different colors use different pigments, and different pigments will have different reactions to the radiation. Some will hold onto the radiation longer than others. That is, the rate of decay is not the same for all pigments. So, if you were to lay a strip of x-ray film over the painting say, five minutes after it was exposed to the radiation, it would pick up one pigment. Lay a strip over the painting after a month, and it would reveal an entirely different pigment. Now, with autoradiography, researchers could see the darker shades underneath, as well as the lighter area, and it allowed them to reconstruct how the paintings were started. And what they were able to see, was the importance of something called the underpainting. Now, underpainting ... okay, underpainting looks like the finished painting, but it was completely done in shades of just one color, usually brown or sometimes grey. So, with underpainting, an artist was better able to envision his final painting. And this confirmed reports from his students, and from others, that Rembrandt didn't work from paper sketches. Basically, he had the whole picture worked out in his mind before ever setting brush to canvas. Another thing the autoradiography confirmed, is that Rembrandt didn't work with a full palette. What I mean is, he'd divide the painting up into sections and work only with those colors he needed for a particular section before moving on to the next. This is quite different from how later painters would work. A 19th Century French artist, like Cézanne, for instance, Cézanne would work on the painting as a whole, using a full palette of colors. It looks like painters of Rembrandt's era only used a full palette at the very end, when touching up an almost finished painting. So we ended up learning more from radiography about Rembrandt's technique, than about how to authenticate his paintings, but it was an amazing project. I mean the researchers were very lucky to have access to these paintings at all. Generally, you can't just take paintings off a museum wall and start analyzing them, especially when this involves removing the paintings from public view for months on end. I'm afraid, in the future, we're going to have to find different methods for analyzing other work.