Dr. Ph. Martin's Hydrus watercolors in 1 oz bottles with dropper caps are made from the finest lightfast, transparent, brilliant and permanent artist pigments. These liquid watercolors are highly concentrated and when used straight from the bottle yield the most vivid colors available to the watercolorist. Add water to achieve the richness of tone you desire and white for pastel and opaque shades. Use with brush, pen, technical pen or airbrush. Also available in sets of 12 in round mixing tray palettes.