Wikipedia
Anthotype
An anthotype is an image created using photosensitive material from plants. This process was originally invented by Sir John Herschel in 1842. An emulsion is made from crushed flower petals or any other light-sensitive plant, fruit or vegetable. A coated sheet of paper is then dried. Place some material, for example leaves or a transparent photo positive on the paper and expose to direct full sunlight until the image is bleached out by the sun rays. The color remains or fades in the shadowed parts. The paper remains sensitive against such rays.