To the student of art it is peculiarly interesting to know about Corot's technical methods of painting, and, fortunately, something of these has been recorded in a series of interesting statements made by Corot to a pupil, which are recorded in M. P. Burty's brief but charming introductory note to the catalogue of the Corot Exhibition, 1875. Corot appears always to have painted on canvas fastened on keyed stretchers, not strained too tightly, and also not covered with any heavy preparation which would make them easily crack—half-primed canvas, English artists would call it. The preparation was sometimes lightly tinted, and he was always very careful in choosing the finest quality of canvas. Having placed the canvas on the easel, Corot seized a piece of white crayon, and, after pausing a moment to consider his subject, he traced with peculiar masterliness and facility the chief masses of the composition. This outline at once became understandable to the onlooker, and from this the artist scarcely deviated in his finished picture, except to fill in details. From this first idea he himself used to foretell the fortunes of the subject. "Look there," said he, "something which shall yet be famous," and then leaving this canvas, to vegetate as it were, he would go to another, or carry forward a third, or complete a fourth, just as he felt inclined.
First ideas were only taken up again after undergoing a certain period of incubation. They were then put once more on the easel to receive the first painting or the sketch of the subject in oil colours. Armed with an ordinary palette, not very carefully arranged, and composed of decided colours, without half-tints, furnished with brushes strong and supple, the painter laid in his groundwork with raw umber, with black and white heightened by raw and burnt sienna and other scientifically good ochres; never, be it observed, with bitumen of any kind. Thus the first plan of his pictures was settled from the point of view of the values and the effect required, by fixing from the first on two extremes—the greatest light and the greatest dark. He emphasized also the principal masses with a firmness sometimes approaching violence, which he toned down afterwards with light transparent colours.
After this the canvas was again put away. Then, when the first painting had become solid enough to be worked upon, the artist sought to produce the complete harmony of his subject by transparent and semi-transparent colours.