It is not true that the esthetic value depends upon the beauty of the selected material.

The men and women whom Rembrandt painted were not beautiful persons.

The ugliest woman may be the subject of a most beautiful painting.

The so-called beautiful landscape may, of course, be material for a beautiful landscape painting, but the chances are great that such a pretty vista will attract the dilettante and not the real artist who knows that the true value of his painting is independent of the prettiness of the model.

He knows that a muddy country road or a dirty city street or a trivial little pond may be the material for immortal pictures.