I translated this from German Wikipedia. I hope it is somewhat understandable.
"In gravure jarring is usually recognizable by blurred and sometimes double contours. Here, the error mainly occurs due to wavy paper sheets, unsteady paper webs, non-uniformly aligned impression rollers and faulty unwinding between impression and impression cylinders.
Jarring permanently destroys the rollers and leads to premature plate wear. It can be turned off by careful maintenance of the elevation heights and precise adjustment of the ink rollers."
source: https://de.wikipedia.org/wiki/Schmitz
here is a example of jarring and a true double print (impression).The 1000 Mark stamp is a true double print.
I thought I will show you this stamp.. I actually forgot I had this stamp Sorry it is crocked I had this checked and they said Not a true double impression of the stamp consequence of jarring in the press/poor printing.
I don't understand what they meant by jarring as wouldn't there be creases on the paper. Help with information please
re: Three Pence kangaroo Stamp
I translated this from German Wikipedia. I hope it is somewhat understandable.
"In gravure jarring is usually recognizable by blurred and sometimes double contours. Here, the error mainly occurs due to wavy paper sheets, unsteady paper webs, non-uniformly aligned impression rollers and faulty unwinding between impression and impression cylinders.
Jarring permanently destroys the rollers and leads to premature plate wear. It can be turned off by careful maintenance of the elevation heights and precise adjustment of the ink rollers."
source: https://de.wikipedia.org/wiki/Schmitz
here is a example of jarring and a true double print (impression).The 1000 Mark stamp is a true double print.