Screen tones are a technique used in comic art and illustration to create shading and texture. They consist of adhesive sheets or films that feature patterns of dots or lines, which can be applied to artwork. By varying the density and arrangement of these patterns, artists can achieve different levels of darkness and visual effects. Originally popularized in manga and comic books, screen tones allow for quick and consistent shading without the need for extensive painting or drawing. Artists can cut and layer these tones to enhance their illustrations, adding depth and dimension to characters and backgrounds.