For more details please do also check my print publication "Holograms on Stamps"
 
 

In 1996 three PortoCards were produced by Deutsche Post AG. These PortoCards are not as rare as the ASTRA PortoCard but they are still missing in many collections.

this PortoCard documents the use of a diffraction foil,

whereas the other two PortoCards bear 2D/3D holograms.