Sunday 10 December 2017

perforation ...

perforation began as line and ended comb type, with many irregularities. 2 machines were applied sometimes simultaneously.  the first line machine was rebuilt with new pins.  centred copies are almost unknown.  missing pins, blunt or sharp perfs, skewed lines and varied proportions are all known.

perforation is one of the keys to plating.  locating the columns on sheets of 100.

slideshow here