Dr. Ph. Martin's Iridescent Calligraphy Colors are shimmering, highly reflective colors that are lightfast, waterproof, archival, and permanent. Made from the finest ground pigments, the unmatched color intensity of Dr. Ph. Martin's Iridescent Calligraphy Colors gives you the ability to cover dark surfaces with a dynamic range of metallic color. Great for use on paper, wood, board, metal, and some plastics. Dr. Ph. Martin's Iridescent Calligraphy Colors dries smooth and even every time. No start and stop marks. Great for use with pens (both calligraphy and dip pens), airbrushes, and brushes. Designed specially for calligraphy, to accent watercolor work, or anywhere where you need to add a magical shine and shimmer that only pigment-based iridescent color can provide.