The Da Vinci Code vocabulary

Fra Bartolommeo only imitated Leonardo in his intense force and soft gradations; the general thinness of colour is opposed to his system. He followed him, however, in his method of painting his shadows with the brush, instead of "hatching" them; he used the same yellowish ground, and "sfumato," [Footnote: Eastlake's Materials for a History of Oil Painting, vol. ii. chap. iv.] i.e. the imperceptible softening of the transition in half-lights and shadows; it was effected by glazes, and is not adapted to a thin substance. The great mistake in Fra Bartolommeo's system was the preparing his paintings like cartoons, and using asphaltum or lamp-black for outlines and shadows; this in process of time destroys the super-colour, and gives a general blackness to the painting.