Abstract: A heat-setting printing ink capable of setting to a stable condition at unusually low temperatures, resulting in time and energy savings for web offset lithographic printing, while effecting superior image integrity or printing quality. The novel lithographic printing ink employs a unique styrene-acrylic copolymer composition, which is dissolved in a low solvency aliphatic hydrocarbon, this being the basic vehicle for the ink. This vehicle exhibits not only a more rapid rate of film formation during drying, but at room temperatures the rate is less than conventional vehicles so as to exhibit good press stability in the roller train. The ink achieves these results without sacrificing other features characteristics of known high quality web offset inks. The ink is formed by blending this special vehicle with other ink composition ingredients including pigments, optionally a conventional let down varnish, a minor amount of additives such as waxes for surface characteristics, and solvent for flow characteristics.