Way back in 1430 a Florentine fresco painter named Cennini advised beginners to draw from nature. “Boys, go out there and draw everything you see.”
In those days paper was scarce, so Cennini told them to spread some ground bone on a board and draw with a stylus. “…Draw something every day, for no matter how little it is it will be well worth while, and will do you a world of good.” (Cennini, Il Libro dell’ Arte)
What is surprising now, looking back, is that both the boys and their master thought they were getting down nature on their tablets. In fact, paintings from those early times don’t show much realism. The drawings look more like each other than like nature. Why? The artists all drew with their minds, not their eyes. They drew the tree in front of them not as they saw it but as their master had drawn it; and they didn’t even know. Nor did their master.
There’s nothing strange in that: we all do it. Even great artists do it for a while. It takes a genius to realize that he is doing it, and to stop.
Why were the boys supposed to go out and draw? Because “[Nature] outdoes all other models…. Do you realize what will happen to you if you practice drawing with a pen?” asks Cennini. “That it will make you expert, skilful, and capable of much drawing out of your own head.”
THAT was the aim: to draw out of your head, to invent your pictures. You copied nature for two reasons: to gain a sure hand and to stock your head with all kinds of details that would be of use when you invented.
A painting was an invented, not a copied thing; and invented according to traditions, conventions. Even the great Leonardo da Vinci kept most of his observations of nature out of his paintings. There are beautiful studies in red chalk of real horses by the master; but his painted animals look no realer than merry-go-round horses. He made hundreds of beautiful and original sketches, close studies from nature; but when he painted a picture, he never even consulted them; which is why more than one of his women have the Mona Lisa smile. Look at his St. Ann. That smile wasn’t on the model in front of him: it was a product of Leonardo’s imagination; and it floated in his mind like the cat’s smile in Alice in Wonderland.
Though all the artists went out and drew from nature, few of their practice drawings have survived, mainly because not even the artist himself thought of them as more than exercises or rough drafts for his “real” work, and tore them up when he cleaned out his workshop (every five years or so?).