Crystal Mint - 22R - Iridescent Calligraphy Colours are shimmering, intermixable, highly reflective, lightfast, pigment based, waterproof, archival, permanent, non-toxic, non-spreading metallic colours. Designed for use with pens, airbrushes, and brushes on black and other dark surfaces, including paper, wood, board, metal, and some plastics. Ideal for cartooning, designing, rubberstamping, lettering, calligraphy, watercolour painting etc.