A size press (SP) surface sizing composition provides a SP surface sizing for a print medium that is used in a digital printing system. The surface sizing composition includes an aqueous mixture including a macromolecular material in an amount from about 25% to about 75% dry weight; an inorganic metallic salt in an amount from about 3% to about 20% dry weight; and an amount of inorganic pigment ranging from at least 16% to about 60% dry weight, such that a total dry weight equals about 100%.