Winsor & Newton's range of calligraphy inks have 18 brilliant and lightfast colours.Brilliant Colours: The inks have been formulated with carefully chosen pigments to ensure maximum colour brilliance. Single pigments have been used where possible to enable clean colour mixes.Versatility for Pen or Brush: 14 colours (blue capped bottles) are suitable for dip pens, fountain pens, technical pens and airbrushes. These colours are transparent, thinner in formulation, fully intermixable and have a satin finish. Four colours (red capped bottles) are thicker, opaque and should be used with a dip pen or brush; this also applies to any mixtures using these colours. The black and white inks have a matt finish.Permanence: Winsor & Newton Calligraphy Inks have a permanence rating of AA or A, but are not waterproof.Flow: The Inks are non-clogging and have good flow characteristics when used in fountain or dip pens. We recommend that you test the inks with your chosen pen to ensure optimum performance.30ml pots.