Review opaque color, also known as multi-level shading. Monochrome painting, to use the old body paint, and then use color multi-level shape, often painted in the dark of the thin, middle-tone and the Department of layers of thick coated, or covered or reservations, a color contrast. Because of different thickness, showing the rich color and texture rhyme intended. Transparent and opaque two oil paintings of the strict law does not distinguish between, often in an artist painting in the comprehensive use. Performance in the dark, or in the shadow of the images, using a transparent review of color can have stability, deep sense of the size and sense of space; opaque color rules easy to follow in the shape of the dark outside the body, increase the screen color saturation. Before the 19th century most of the artists using these two oil paintings, works of the time normally produce a longer, and some Huawan after a long-term placement, color layer to be completely dry before to describe.