SolarFast dyes are light-sensitive and only develop color and become permanent upon exposure to sunlight (UV). This unique property means SolarFast may be used to create remarkably detailed photographs, photograms and shadow-prints on paper or fabric by harnessing the power of the sun! SolarFast is also great for painting, tie dyeing, screen printing, stamping, batik and more. This package contains 4oz of SolarFast Dye. Conforms to ASTM D 4236. Comes in a variety of colors. Each sold separately. Made in USA.