Waterproof drawing pens allow you to sketch or outline your work and then add colour or tints using anything from watercolour paint through to alchol-based marker pens without the lines smudging or running. The key ingedient is pgment ink, which contains tiny particles of colour that bind tightly to paper fibres, unlike dye-based inks which will usually run and bleed when washed over. These pens are also known as Pigment Liners, fineliners or sketching pens. Popular brands include Staedtler 308, Uni Pin and Sakura Pigma. Most models have a range of tip sizes with a fine, porous metal-clad point. Black is the commonest ink colour, but many of our ranges are available in a range of ink colours.