Winsor & Newton Calligraphy Inks are formulated with carefully chosen pigments to ensure maximum brilliance of color. They are lightfast, non-waterproof, non-clogging, and particularly suited for calligraphy.Gold, silver, white, and matte black are suitable for use with dip pens and brush. All other inks are suitable for use with dip pens, fountain pens, technical pens, and brush.Single pigments have been used wherever possible to make clean color mixtures. All colors have a permanence rating of AA or A. The inks come in 30 ml bottles.