An offset printing method includes creating halftone dots corresponding to a printed image and formed of printing ink, on a surface of a transfer cylinder and transferring the halftone dots to a printing substrate while the transfer cylinder rotates about its longitudinal axis. A halftone value in a printed image on the printing substrate is adjusted to a desired value by modifying a halftone dot size. The offset printing method improves the quality of the printed image by increasing the halftone dot size by a desired amount by providing a relative offset between a device that creates the halftone dots and the surface of the transfer cylinder.