Dr. Ph. Martin's Spectralite private collection liquid acrylics are the brilliant, lightfast, waterproof acrylics that flows like watercolor. The permanent, archival grade fine art color is made with the finest ground pigments sourced from around the world. Excellent on paper or canvas, Spectralite can also be used on board, wood or metal. Also works for illustration, calligraphy pens, airbrushing, designing and technical pens.