1. An intaglio printing press comprising an inspection system for in-line inspection of sheet or web material on the intaglio printing press, wherein the inspection system comprises an optical quality control apparatus for carrying out inspection of a printed area on a printed side of the sheet or web material, the optical quality control apparatus including a camera system with one or more camera units each comprising at least one line-scan camera for scanning and acquiring an image of the printed area while the sheet or web material is being transported in the intaglio printing press past the camera system, wherein a location of the at least one line-scan camera in the intaglio printing press along a delivery path of the sheet or web material is such that cyclical vibrations that spread periodically throughout the intaglio printing press during operation of the intaglio printing press do not occur while the camera system is scanning the printed area of the sheet or web material and acquiring a complete image of the printed area, wherein the camera system comprises a single camera unit disposed transversely to the path of the sheet or web material for scanning an entire width of the printed area of the sheet or web material, wherein a distance along the delivery path between a printing location where printing of the sheet or web material occurs and an inspection location where the camera system acquires an image of the printed area of the sheet or web material is an integer multiple of the distance separating two successive printed samples of the sheet or web material, which is the distance between a leading edge of a sheet or web material to a leading edge of an immediately following sheet or web material, and the distance includes a length of an impression cylinder pit, wherein the intaglio printing press is designed for processing sheet material, and wherein the camera system is located along the path of a sheet conveyor system comprising a pair of endless chains driving spaced-apart gripper bars for holding a leading edge of the sheet material, and wherein the intaglio printing press further comprises at least one sheet-guiding member for supporting a backside of the sheet material opposite the printed side in the region of the inspection location.