Ink is a liquid or paste that contains pigments or dyes and is used to color a surface to produce an image, text, or design. Ink is used for drawing or writing with a pen, brush, or quill. Thicker inks, in paste form, are used extensively in letterpress and lithographic printing.
Ink can be a complex medium, composed of solvents, pigments, dyes, resins, lubricants,solubilizers, surfactants, particulate matter, fluorescents, and other materials. The components of inks serve many purposes; the inks carrier, colorants, and other additives affect the flow and thickness of the ink and its appearance when dry.