Artists use light and shadow to create contrast and drama in their artworks by manipulating the intensity, direction, and quality of light in their compositions. By varying the contrast between light and shadow, artists can emphasize certain elements, create depth and dimension, and evoke different moods or emotions within their pieces. They often use techniques such as chiaroscuro (the use of strong contrasts between light and dark), sfumato (softening transitions between tones), and dramatic lighting effects to achieve the desired impact in their artwork.