When you pay attention to shadows, the improvement to your renderings can be well worth the effort and experimentation you invest in them. Ask yourself some questions about the use of shadows that you see in movies and photographs that you admire, and in your own work.
Rent a movie, and pause it at some specific frames. Where do you see shadows? Are they all cast from the same light? Are the shadows hard or soft? Does the darkness of the shadows seem to match the level of contrast in the scene?
Examine a close-up picture of a person. Are there shadows on the person's face? Can you tell the angle of the lighting from the shadows?
Look at some of the renderings you have created previously. Do the shadows serve any of the visual functions that were mentioned in this chapter? Are the quantity, darkness, and softness of the shadows appropriate to the scene? Is there enough secondary shadowing in the shadow areas?