Dr. Ph. Martin's Radiant Concentrated Water Color is a range of 56 colors produced in an extremely concentrated form to achieve the greatest possible brilliance. Each transparent, dye-based color comes in its own dropper-top 0.5 oz glass bottle. Radiant Concentrated colors are primarily formulated for use in graphic arts work on paper surfaces intended for reproduction (e.g. cartooning, illustration, and other graphic arts), and are especially popular for airbrushing. Like all aniline dye-based colors, they are fugitive when exposed to direct sunlight over time. Great for use with a brush and will not clog your technical drawing pen or airbrush.