Hi KGV Collector OFFSET
In making the stamps, sheets of watermarked paper are printed between two rollers, somewhat like a huge mangle used on vintage washing machines. One roller contains the printing plate, made cylindrical, and fitted to its surface; the other steel roller is merely used to press the paper firmly against the inked surface of the plate.
The vertical stamps have what is known as a series of partial offsets. An offset is caused when a printing press is set into motion without any paper fed into it, then the impression of the stamps will be printed on to the pressure roller with wet ink, so both rollers are now printing plates, and the next sheet to go through them will receive a printing on both sides.Offset
Dry inking is seen only on the front of the stamp, this may be caused by not enough ink added to the plate, or that the ink was not of the correct viscosity (thickness) and the doctor blade removed too much ink in the process.Dry inking