Serigraphs are created by forcing ink through a series of fine meshed silk-screens. Each silk-screen is stretched tightly over a firm wooden or aluminum frame and is most typically coated with a photo-sensitive emulsion, although adhesive film is also used sometimes to create a mask. The chromist creates a separation by painting an opaque medium onto a clear piece of Mylar or acetate. This film is then transferred to a silk screen coated with photo-emulsion, and is then exposed to intense light. The emulsion exposed to the light becomes "cured" or hardened, and the areas blocked by the opaque separation on the Mylar remain soft and uncured. The uncured areas of the silkscreen are then washed out using a high pressure spray gun.