Inks manufacturers manufacture ink, a liquid that contains pigments or dyes. Inks are used to colour a surface to produce an image, text or design. Ink is used for drawing or writing with a pen or a brush. Thicker inks, in paste form, are used extensively in letterpress and lithographic printing. Inks can be carbon inks, iron gall inks and indelible inks. Inks fall into four classes, aqueous, liquid, paste and powder.