To see how Michelangelo carved, let’s look at his unfinished statues, especially the ones that are only blocked out. They should tell us, shouldn´t they?
They should but they don´t. They rather keep the mystery. It´s as if the old master, like a sly Merlin, had locked up his secret in them forever. You can´t study them without confusion. Sculptors for five hundred years have not agreed on how Michelangelo proceeded, though they had these enigmatic works right in front of their noses.
Take the St. Matthew.
See the enlarged photo here
“Rough as it is”, says Vasari, “this is a perfect work of art which serves to teach other sculptors how to carve a statue out of marble without making any mistakes, perfecting the figure gradually by removing the stone judiciously and being able to alter what has been done as and when necessary.”
It doesn´t teach that at all. The most striking thing about it is that it looks like a RELIEF! Only the front half is carved, as if Michelangelo, like a painter, were interested in only the front view. As if he carved ignorantly away like a beginner without worrying about the depth of the features and how they would look from another angle. As if he could leave the backside of St. Matthew to take care of itself. This is a terrible example of how to carve, a treacherous example for sculptors, who often err in just this way.
Why DID he carve like this?
Easy: he wanted to enjoy himself, the same as the ignorant beginner, the same as the child who draws with his pretty crayons on a sheet of paper. Though he consulted his dusty model on a table near him, and though it was finished in detail, in his mind he went back to the original idea he had had—and started all over again to capture it in stone, for which it was intended.
He was terribly impatient to see the results, to work out the figure. He wanted it right now. He knew it was going to be gloriously good and he couldn´t wait to see it. Chipping out the whole figure little by little in the traditional way took much too long. The hell with the traditional method! He had already seen with his very first stone statue that if he did what they said he would never finish a statue in marble. By the time you got down to the flesh of your figure, you had almost lost your original idea, together with your enthusiasm for it. It took weeks while you measured and measured until you were blue and still couldn´t really see your figure clearly. That was nonsense. He would come up with his own method—a method that would let him have all the fun of drawing. Somehow he would handle the depth thing.
How he did that is unknown.
See how Vasari, his biographer, says Michelangelo carved.