Cyanotype is a type of printing where UV rays are used to imprint the color onto a surface. A negative of an image or an object is placed onto the coated surface and left in sunlight or under a UV lamp. The solution will begin to change color during exposure. The exposed part of the paper will fade in the UV exposure. Once fully processed, the paper is rinsed with water and an image of the negative or object develops is left behind with a blue (or other colored) background.