Maximum brilliance of color. Blue capped bottles are fully intermixable and intended for use with dip pen fountain pen technical pen and airbrush. Red capped bottles are opaque and suitable for dip pen and brush. Unrivaled permanence and quality. Non-waterproof to ensure no clogging and good flow characteristics when used in fountain or dip pens. Lightfast. Set includes 6 inks: Green Dark Blue Gold Sepia Black and Crimson. Colors subject to change.