Learners experiment with a commercial photo-sensitive paper (Sunprint® or NaturePrint® paper). They place opaque and clear objects on the paper and expose it to bright light, observing the results. Chemicals in the paper react when exposed to light. No reaction occurs where opaque objects are placed on the paper and block the light. The light reactions stop when you rinse the paper with water. Sunprint® paper can use sunlight or artificial light. Use this activity to introduce learners to the chemical processes to develop blueprints, photographs, and photocopier pages as well as the process of photosynthesis in nature.