This term is used to describe varying degrees of denseness with regard to color, smell or taste. In the fields of art and literature, it refers to the denseness or lightness of a painting's color, ornateness or plainness of literary language, boldness or restraint in artistic style, or to directness or opaqueness of emotional expression.
Denseness and lightness are relative to each other. In traditional Chinese painting, for example, the colors chosen can either be dense or light, but they should not be so dense as to be crude or so light as to be insipid. Ink wash painting pays particular attention to the denseness or lightness of color, aiming to achieve a balance between the two. This implies a harmony between the bright and the shady, the front and the rear views, the tangible and the intangible, density and sparsity, and the long- and short-range views. An ideal painting expects denser and lighter hues to set each other off beautifully. This requirement applies also to other genres of art.
A piece of writing is like the shutters on a window, with the left and right sides balanced and well matched. Wording is like a river — if too full, it will flood. We must weigh to see if it needs abridgements or additions, or if it is too ornate or too plain. Any superfluous part should be deleted and any jumbled mass cleaned up so that the composition may not be weighted down. (Liu Xie: The Literary Mind and the Carving of Dragons)
The artistic conception of this painting is tranquil and detached. Although small in size and sketchy, it intersperses stronger and milder hues, and heavier and lighter patches. Clouds, mists, mountains, and rivers present themselves in a variety of ways, keeping the eye busy taking it all in at once. It must be the painter's own favorite piece of work. (You Mao: Postscript to Mi Youren's "Landscape Painting of Hills and Rivers in Hunan")