Michelangelo’s Fresco Painting Technique

It's known that his basic approach was a standard technique called Buon Fresco, which is still taught at places like this international conservation organization in Rome. The chief conservator is Paul Schwarzbahn, now with the Guggenheim Museum. He explains what has been learned from the restoration about Michelangelo's technique. We're going to try and make a reproduction, if you will, to recreate the working technique of Michelangelo, the way he painted the frescoes of Sistine Ceiling. We're going to use the same materials and we're going to try as best we can to, not Michelangelo, but to recreate his working technique. The materials that you see on the floor, we know from analysis, these are the materials that Michelangelo used to make his plaster. The plaster is made from lime, water, and a brown volcanic ash called pozzolana. These are mixed into a smooth violet colored paste. The plaster is applied to a surface prepared the day before called the oricio. This fresh wet layer, the intonico, is applied just before painting. The word fresco in Italian means fresh, and what it means is that we're painting on the fresh plaster. The painter was obliged to work before the plaster dried. Now this means that the plaster could only be applied little by little as the painter worked in terms of what he thought he might finish in a day or before lunch or what have you. There's a word in Italian which is called the giornata. We know from cleaning of the Sistine that colors are very bright and Michelangelo wanted these bright colors. To do that, we see that in certain areas he put on at the very end, just before he painted, a very bright white, more white let's say, very, very, very thin layer of preparation, but very rich in lime, very thin. It would be a millimeter or two thick what he's putting on now, like a sheet of paper. After the plaster is applied, the design is transferred using cartoons, drawings on paper. The contours of the figure are incised into the wet plaster, sometimes using a piece of wood. A different technique is used to outline the details around the face. The other technique is called spolvero in Italian and probably called a pouncing technique in English. We make a series of small holes along the lines in certain very key points. Michelangelo, we see, did the eyes, the nose, the mouth, the ears, the throat, and then takes a little sack of charcoal or some powdered pigment and then you'll see the pigment goes through the holes and leaves the design on the fresco, so he has something to use as a guide for painting. You see, that would be how Michelangelo transferred his design, and with that it gives you a base for painting. Michelangelo mixed ground pigments with water. He used just seven colors derived from minerals found in earthen clays. For his greens, he used green earth, ochres for his yellows and reds, and cobalt or lapis lazuli for the blues. When Michelangelo applied the colors to the wall, they had a translucent quality like watercolor, but as the plaster dried, a process called carbonation took place. Carbon dioxide in the air combined with the lime in the plaster to form a hardened rock-like surface of calcium carbonate. As a result of this process, the pigment particles were cemented in place, becoming a part of the wall. The standard fresco technique is a rather stable technique. When it's done well, it lasts thousands of years. We have Roman frescoes that are close to 2,000 years old. But did Michelangelo vary the standard technique in any way, embellish it perhaps by adding any other layers of paint or glue varnish to the surface of the fresco? Unfortunately, there is no complete record of Michelangelo's working technique. In letters to his family, he did write about painting the chapel, but he mostly complained of the uncomfortable working conditions. In front, my skin grows loose and long, my head is bent back on my shoulders, and my paintbrush drips a rich mosaic onto my face.