Processes for producing optical effects layers

A process for producing an optical effect layer on a substrate, said process comprising the steps of:

• a) applying onto a substrate surface a coating composition comprising platelet-shaped magnetic or magnetizable pigment particles so as to form a coating layer on said substrate, said coating composition being in a first state,
• b) placing the substrate carrying the coating layer on a first magnetic-field-generating device providing a first magnetic field vector component, said first magnetic-field-generating device being mounted on a transferring device thereby subjecting the platelet-shaped magnetic or magnetisable pigment particles to said first magnetic field vector component,
• concomitantly moving said substrate carrying the coating layer and said first magnetic-field-generating device in the vicinity of a static second magnetic-field-generating device, said second magnetic-field-generating device providing a second magnetic field vector component
• thereby subjecting the platelet-shaped magnetic or magnetisable pigment particles to a time-dependent resultant magnetic field formed by the first and second magnetic field vector components so as to bi-axially orient at least a part of the platelet-shaped magnetic or magnetizable pigment particles,
• wherein the ratio of the magnetic flux density of the first magnetic-field-generating device and the magnetic flux density of the second magnetic-field-generating device is less than about 4.0;
• and
• c) hardening the coating composition to a second state so as to fix the platelet-shaped magnetic or magnetizable pigment particles in their adopted positions and orientations.