Learning to carve

Photographs and text by Marc Levoy
October 14, 1999

One of the unique features of Michelangelo's statues is that many of them are unfinished. Best known among these are the four Slaves and the apostle St. Matthew. In these works, the master's chisel marks are clearly visible. As the months of preparation for our scanning project neared completion in the Autumn of 1998, questions repeatedly arose about these chisel marks:

How much detail must we capture to enable scholars to study these chisel marks?
How important is color to the study of these marks?
Why are the bottoms of the chisel marks white?
What kind of tool made this mark, or that one?

In the end, I decided that the only way to learn the answers to these questions was to learn how to carve. I'm no artist, but I was trained as an architect, and I can sketch a bit, so the experiment seemed worth trying. Besides, my mother is a sculptor; perhaps my genes would lend a hand. Fortunately, I knew a sculptor in Florence, Matti Auvinen, who had served as our guide when we toured the marble quarries of Pietrasanta. Matti was intrigued by our project to scan the statues of Michelangelo, and he readily agreed to give me private carving lessons. He later proved to be an invaluable advisor to the project when questions arose about the carving techniques of Michelangelo.

The classic "first piece" for an apprentice marble carver is a mortar (and pestle). Having been trained as an architect, and not having the good sense to keep my first piece simple, I designed a large one, buttressed by scrolls and resting on an elaborate base. Matti, seeing that he could not dissuade me from my ambitious plan, bought me a long block of Carrara Statuario, the white marble favored by Michelangelo, and we began my apprenticeship.

To Matti's amusement, I refused to use a pneumatic chisel - the standard tool of modern sculptors. I wanted to use hand chisels - the tools of Michelangelo. Matti warned me that these are harder to use, and that it would slow the work. With visions of Irving Stone's The Agony and the Ecstacy filling my head, I insisted, and he acquiesced. He taught me the different types of hand chisels, how to sharpen them, how to use them, and what working strokes Michelangelo may have employed. Pictured here from right to left is a "subbia", used for rough work, a three-tooth chisel, used for shaping curved surfaces, two flat chisels, used for refining details, and a rasp, used for details too delicate to withstand the blows of a hammer. (Michelangelo's toolkit would have looked somewhat different; he used a flattened subbia called an "ugnetto" and a two-toothed chisel called "dente di cane" - dog's tooth.)

After a month of labor (working two afternoons a week), I've roughed out the bowl of my mortar and two of the three buttresses that will become scrolls. The intended shape of these scrolls is drawn on the side of the block. To hold my piece steady while I work, I have left it attached to the original block, which weighs about 75 pounds.

I made good progress on the piece until Christmas. However, in January of 1999 we moved our equipment into the Galleria dell'Accademia and began scanning Michelangelo's statues. For the next five months I had very little time for hobbies. Finally, as Spring turned to Summer and our scanning schedule eased, I set up a workbench in the courtyard of my villa and, in a few weeks of concerted effort, finished shaping the piece.

The process of smoothing and polishing a marble sculpture consists of making ever-smaller scratches in its surface. Pictured here from right to left below the chisels are two carborundum stones of varying roughnesses, two grades of sandpaper, a square of fine emery paper, and vials that contain polishing powder and oxalic acid. Mixed together and applied (with elbow grease) to the smooth marble surface, they can bring it to a high sheen. At the right is a sculptor's hammer, whose head is made of soft iron to absorb the shock of repeated blows against the ends of the chisels.

Here is the finished piece. The base, rim, and scrolls are polished, the bowl is smooth but unpolished, and the connective tissue between the bowl and scrolls is rough, in fact textured with a chisel. The piece stands 6 inches tall, weighs about 10 pounds, and now graces the display case in my office at Stanford. Next to it are the terra-cotta Stanford bunny and the original and 3D fax of the Happy buddha.

What did I learn from this experience? Well, I learned the answers to some of my questions about Michelangelo's chisel marks. The bottoms of chisel marks are white because the marble crystals there have been crushed by the impact of the chisel. On a personal level, I learned that carving marble is hard work. Accustomed to exercising mainly by bicycling, my hands and arms grew considerably during the year. Judging from the depth and length of his furrows, Michelangelo must have been immensely strong. I also learned that marble is an unforgiving medium. The process of carving is entirely subtractive. Mistakes cannot be fixed, except by changing the design. A single blow made with the chisel angled incorrectly can crack a block or break a delicate protrusion. I know this from sad experience; my piece is not exactly as I originally designed it. Finally, I learned the enormous satisfaction that comes from creating something enduring with my own hands. Long after the data from the Digital Michelangelo Project has been lost or superceded, my little stone mortar will survive.

levoy@cs.stanford.edu

	The classic "first piece" for an apprentice marble carver is a mortar (and pestle). Having been trained as an architect, and not having the good sense to keep my first piece simple, I designed a large one, buttressed by scrolls and resting on an elaborate base. Matti, seeing that he could not dissuade me from my ambitious plan, bought me a long block of Carrara Statuario, the white marble favored by Michelangelo, and we began my apprenticeship.
	To Matti's amusement, I refused to use a pneumatic chisel - the standard tool of modern sculptors. I wanted to use hand chisels - the tools of Michelangelo. Matti warned me that these are harder to use, and that it would slow the work. With visions of Irving Stone's The Agony and the Ecstacy filling my head, I insisted, and he acquiesced. He taught me the different types of hand chisels, how to sharpen them, how to use them, and what working strokes Michelangelo may have employed. Pictured here from right to left is a "subbia", used for rough work, a three-tooth chisel, used for shaping curved surfaces, two flat chisels, used for refining details, and a rasp, used for details too delicate to withstand the blows of a hammer. (Michelangelo's toolkit would have looked somewhat different; he used a flattened subbia called an "ugnetto" and a two-toothed chisel called "dente di cane" - dog's tooth.)
	After a month of labor (working two afternoons a week), I've roughed out the bowl of my mortar and two of the three buttresses that will become scrolls. The intended shape of these scrolls is drawn on the side of the block. To hold my piece steady while I work, I have left it attached to the original block, which weighs about 75 pounds.
	I made good progress on the piece until Christmas. However, in January of 1999 we moved our equipment into the Galleria dell'Accademia and began scanning Michelangelo's statues. For the next five months I had very little time for hobbies. Finally, as Spring turned to Summer and our scanning schedule eased, I set up a workbench in the courtyard of my villa and, in a few weeks of concerted effort, finished shaping the piece.
	The process of smoothing and polishing a marble sculpture consists of making ever-smaller scratches in its surface. Pictured here from right to left below the chisels are two carborundum stones of varying roughnesses, two grades of sandpaper, a square of fine emery paper, and vials that contain polishing powder and oxalic acid. Mixed together and applied (with elbow grease) to the smooth marble surface, they can bring it to a high sheen. At the right is a sculptor's hammer, whose head is made of soft iron to absorb the shock of repeated blows against the ends of the chisels.
	Here is the finished piece. The base, rim, and scrolls are polished, the bowl is smooth but unpolished, and the connective tissue between the bowl and scrolls is rough, in fact textured with a chisel. The piece stands 6 inches tall, weighs about 10 pounds, and now graces the display case in my office at Stanford. Next to it are the terra-cotta Stanford bunny and the original and 3D fax of the Happy buddha.