A process for producing an optical effect layer (OEL) on a substrate, the OEL comprising a motif made of at least two areas made of a single applied and cured layer, the process comprising the steps of:
- a) applying, on the substrate, a radiation curable coating composition comprising non-spherical magnetic or magnetizable particles so as to form a coating layer, the coating layer being in a first state, said first state being a liquid state;
- b) b1) exposing the coating layer to the magnetic field of a first magnetic-field-generating device thereby orienting at least a part of the non-spherical magnetic or magnetizable particles,
- b2) at least partially curing one or more first areas of the coating layer to a second state so as to fix the non-spherical magnetic or magnetizable particles in their adopted positions and orientations;
- the at least partially curing being performed by irradiation with an actinic radiation LED source so as to at least partially cure the one or more first areas of the coating layer and such that one or more second areas of the coating layer are not exposed to irradiation,
- wherein step b2) is carried out partially simultaneously with or subsequently to step b1);
- and
- c) at least partially curing the one or more second areas of the coating layer so as to fix the non-spherical magnetic or magnetizable particles in their adopted positions and orientations in the one or more second areas;
- the curing being performed by a radiation source, wherein step c) is carried out after step b2);
- wherein step c) consists of the two following steps:
- c1) exposing the coating layer to the magnetic field of either the first magnetic-field-generating device or of a second magnetic-field-generating device thereby orienting at least a part of the non-spherical magnetic or magnetizable particles;
- and
- c2) the step of at least partially curing the one or more second areas of the coating layer so as to fix the non-spherical magnetic or magnetizable particles in their adopted positions and orientations in the one or more second areas;
- the curing being performed by a radiation source,
- wherein said step c2) is carried out partially simultaneously with or subsequently to said step c1);
- wherein the actinic radiation LED source comprises an array of individually addressable actinic radiation emitters,
- wherein the actinic radiation is projected onto the coating layer to form one or more projected images, and
- wherein the actinic radiation of the actinic radiation LED source is projected by a projection means onto the coating layer under size reduction of the one or more projected images of the actinic radiation source.