Abstract: An apparatus is provided for attachment to the down-stream end of a conventional offset lithographic printing press for in-line coating of the printed work issuing from the press, with water-based polymer coatings, to protect the printing ink as the printed matter sets and hardens. The apparatus includes a pick-up roller which picks up liquid coating composition from a reservoir structure, a cylindrical applicator roller to which the coating composition is transferred, the apparatus being mounted on the frame of the press so that the applicator roller of the apparatus can bear against the blanket roll of the printing press and transfer the coating composition to the blanket roll as the press operates. The apparatus is releasably mounted to the press, and can be pivoted about a lower axis to bring the applicator roll into and out of contact with the blanket roll of the press.