These inks are made in 18 lightfast colours with carefully chosen pigments to ensure colour brilliance. The 14 blue-capped bottles contain thinner, more transparent inks with a satin finish. They're suitable for dip-pens and airbrushes. Please note these are not suitable for fountain pens. W & N's four red-capped bottles are opaque and should be used with a dip-pen or brush. Winsor & Newton Calligraphy Inks have a permanence rating of AA or A but are not waterproof.