Light creates shadow and shadow in return, enhances the appearance of the subject. The interaction of the two is fascinating. Light can make the subject feisty or dull while shadows can make it mysterious or terrifying.
Shadows add facet and meaning to an image. Without shadows the object may appear plain and boring. Lights and shadows establish the correlation of one object to another and their place in the full scene.
The position and strength of the lights and shadows also set the general mood of the subject.Shadows are also essential in some types of arts like painting, photography and stage play.