Dr. Ph. Martin's Iridescent Calligraphy Colours are shimmering, highly reflective colours that are lightfast, waterproof, archival, and permanent. Made from the finest ground pigments, the unmatched colour intensity of Dr. Ph. Martin's Iridescent Calligraphy Colours gives you the ability to cover dark surfaces with a dynamic range of metallic colour. Great for use on paper, wood, board, metal, and some plastics. Dr. Ph. Martin's Iridescent Calligraphy Colours 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 watercolour work, or anywhere where you need to add a magical shine and shimmer that only pigment-based iridescent colour can provide.