Even the former head of the German State Printing works where most of the German stamps had been printed - mr Hans Zerbel - told me after having been given copies of my stamps [!!!!] that there was NO screen and what I must have seen was a structure of the paper surface!


The Calvin stamp is the only one with a 70 degrees angle! All the other have a 45 degrees angle.
So far my earliest copy of a German stamp with this phenomenon is from 2005!
to be continued ...