The present invention concerns a security thread or stripe for the incorporation into or onto a value-document or currency substrate, as well as a method and means of making such thread or stripe. The thread or stripe comprises a plastic foil which carries a hardened coating comprising oriented magnetic or magnetizable pigment particles, the orientation of said pigment particles representing graphic information. Preferred are optically variable magnetic or magnetizable pigment particles. Said hardened coating may also be comprised between a first and a second plastic foil. Said graphic information is a repetitive seamless pattern of suitable repetition length, which is produced using a magnetic orienting cylinder having a corresponding repetitive seamless magnetic field pattern. A magnetic orienting cylinder and a process for process for producing such magnetic orienting cylinder are also disclosed. The process comprises the coating of a cylindrical support body with a polymer material comprising a high-coercivity permanent-magnetic powder as a filler material, and magnetizing or engraving the seamless outer cylinder surface to form on the cylinder a repetitive seamless magnetic field pattern.