Processes for in-field hardening of optical effect layers produced by magnetic-field generating devices generating concave field lines

摘要

The invention relates to the field of the protection of security documents such as for example banknotes and identity documents against counterfeit and illegal reproduction. In particular, the invention relates to a method for freezing the orientation of orientable magnetic or magnetizable pigment particles by irradiation hardening the coating layer comprising the orientable magnetic or magnetizable pigment particles through the substrate carrying the coating layer.