In the summer, crisp white sheets look even more inviting edged with prints made from a few flawlessly shaped scallop shells -- beachcombing for the perfect candidates is half the fun of this project.
Apply fabric paint directly to the shell's surface with a sponge brush, but do so sparingly; you don't want it to fill in the grooves. Move the painted shell to a clean work area, and carefully place your fabric on top of it. Rub the cloth lightly to transfer the image, then gently lift it off. Wipe the shell clean before making the next impression.
Make practice prints until you are comfortable with the technique and can line up several prints neatly in a row. Test the fabric first, too: tightly woven cotton will pick up the most-detailed images. Follow paint manufacturer's instructions for colorfastness.