Shadows convey a tremendous amount of information, and the incorrect presentation of shadows can weaken a painting. Some of these seem obvious, but they are worth reviewing.
Here are a few pointers:
All going the SAME WAY: It’s basic but, make sure all the shadows run in the same direction. If they run in more than one direction, there had better be more than one light source!
Correct VALUE SHIFT: The value relationship between the sunny side and the shadow side of an object describes the light intensity of the day. A large contrast implies a sunny day; a tight value relationship implies a day with a lot of atmosphere. Think of the high contrasts in a black and white picture of the surface of the moon with its air less atmosphere and bright sun, compared to a smoggy day in Los Angles. The value shift between the sunny side and shadow side on a hazy day is much less than that on a clear bright day.
Watch those EDGES: The transition from dark to light on an object turning away from its light sourse describes the nature of the surface on which the transition is taking place. For example, the corner of a box is described by an abrupt straight value shift. The shadow on a ball occurs more gradually. A flatter curve has an even longer area of value shift. Details like this become very important when rendering the irregular surface of leaves or petals. On a face the correct edge location an transition width can make the difference in achieving a successful likeness.
The edges of cast shadows frequently DESCRIBE the object which cast them. For example, on the face again, a nose casts a hard edge cast shadow across an upper lip, but the edge cast by a mop of hair is soft.
SHADOW INTERRUPTED: When painting a landscape, a shadow can help anchor an object and create a sense of distance. Lighter silhouettes that cut into the shadow shape from below imply objects in front of the cast shadow. Likewise, objects, such as grasses in the shadow area extend above the shadow shape. Shadows cast across a rutted road go up and down with the surface of the ruts. Unless something in the foreground blocks your view, the cast shadow should connect to the object that casts it hense anchoring it into place.
Basically, pay attention. Just because a shadow is not an actual “thing” it IS still integral to the overall success of a realistic painting or drawing. All this and we haven’t even touched the many aspects of color in shadows. That will have to wait till another day.
