Cyanotype is an antique photographic printing process, developed in the mid-1800s and distinctive for its rich blue color. This package of 30 (thirty) 8½ in. x 11 in. high-quality cotton sateen fabric sheets have been pre-sensitized by Jacquard for cyanotype. Ready to use, they making sun printing easier than ever before. When the cyanotype fabric is exposed to sunlight (3-15 minutes), a chemical reaction occurs. It won't reveal itself, though, until you submerge the fabric in cool water, when it will quickly turn blue! Anything that casts a shadow will produce an image: plants or leaves, toys, tools, stencils, stones, sand, feathers, paper cutouts, string, lace or doilies. To make prints of photographs, just print the photo onto a transparency and place that on top of the fabric instead of an object. Anywhere the sunlight doesn't touch will remain white and leave an impression on the fabric. Complete instructions are included. CONTENTS ARE LIGHT-SENSITIVE: do not remove from bag until you are ready to make a cyanotype print.