Just add sunlight and water to demonstrate a chemical reaction caused by ultraviolet light. At the same time you can create a photographic work of art! Put one or more objects on a sheet of this photosensitive paper and expose it to sunlight for several minutes. Then dip the paper in water and watch the “print” develop. The image appears in minutes and the print becomes permanent. Sheets measure 12.6 cmx 17.7 cm and come 30 sheets per package.