There is described a printing press adapted to carry out printing on a sheet-like or web-like substrate, in particular for the production of security documents such as banknotes, comprising a substrate feeding device for feeding the substrate to be treated, at least a printing unit designed to print a first side and/or a second side of the substrate and a delivery unit for receiving the treated substrate. The printing press in the conveying path for the substrate between the feeding device and the delivery unit further comprises an in-line casting device adapted to apply a layer of material acting as an optical medium on a portion of the second side of the substrate and to replicate and form a micro-optical structure in the layer of material acting as optical medium, wherein the printing unit comprises a first printing group comprising a printing cylinder and being adapted to print at least one printed pattern on the first or second side of the substrate in register with the micro-optical structure.