Artists use the concept of space, both positive and negative, in their compositions to create a sense of depth, balance, and visual interest. Positive space refers to the area where the subject or objects of focus are placed, while negative space is the area around and between the subjects. By manipulating positive and negative space, artists can create emphasis, movement, and a sense of atmosphere in their artworks. They play with these spaces to draw the viewer's eye to certain areas, create tension or harmony, and convey emotions or messages effectively.