Magnetic assemblies and processes for producing optical effect layers comprising oriented non-spherical magnetic or magnetizable pigment particles

A magnetic assembly for producing an optical effect layer on a substrate, said magnetic assembly being configured for receiving the substrate in an orientation substantially parallel to a first plane and above the first plane, and further comprising:

• a) a first magnetic-field generating device comprising three or more first dipole magnets (x31ai, each of said first dipole magnets having its center (Cx31-ai) disposed on a loop in the first plane,
• wherein said first dipole magnets (x31ai) have their magnetic axes oriented to be substantially parallel to the first plane, wherein said first dipole magnets (x31ai) are at least partially embedded in a supporting matrix;
• and
• b) a second magnetic-field generating device comprising a second dipole magnet (x41) having its magnetic axis oriented to be substantially perpendicular to the first plane and being arranged to have a projection of its center on the first plane be located at a projection point (Cx41) within the loop,
• wherein the second magnetic-field generating device is disposed above the first magnetic-field generating device,
• wherein angles αi are formed between each of the vectors {right arrow over (Cx41Cx31-ai)} and the vector {right arrow over (hx31-ai )} of the magnetic axis of the respective first dipole magnet wherein all of the angles αi, when measured in a counterclockwise direction, are in the range from about 20° to about 160° or in the range from about 200° to about 340°, and
• wherein each of the first dipole magnets (x31ai) is disposed at a first distance, said first distance being on the first plane between the projection point (Cx41) and the center (Cx31-ai) of the first dipole magnet (x31ai).