Proportion applies to sculpture as to painting; perspective determines the contour; chiaroscuro gives relief through the disposition of lights and shadows in their relationship with the background; color gives the appearance of life.. .The colorists, the men who unite all the phases of painting, have to establish, at once and from the beginning, everything that is proper and essential to their art. They have to mass things in with color, even as the sculptor does with clay, marble or stone; their sketch, like that of the sculptor, must also render proportion, perspective effect, and color.