Re: thinner plates/spider webbing
> what is spider webbing?Brian
Sounds funny coming back.
Well... there are different effects if the roller is out of
adjustment. Most common would be a "paneling" effect across the floor
of the plate. Quite obvious the rollers are completely out of whack,
either that or there is no type high thing going on with base and
plate and bed.
Spider "webbing" is more a slight touchdown due to an oscillating
roller or worn roller mechanism. As the roller slowly deviates from
its setting, a slight tracking of ink the repeats itself along the
floor of the plate during each additional impression( unless of course
you catch it right away, ha!). The roller bearers and associated
mechanisms on a Vandercook (specifically) weren't exactly designed for
editioning. I've never seen a Vandercook that didn't oscillate to one
degree or another. I've never used a platen jobber with photopolymer
(I assume there is probably a similar effect).
Another indicator is "nicking" (I've seen this referred to as
"spitting"). Where the roller is inking an errant occurrence, a stray
fragment of photopolymer left near type high due to cutting, etc., say
if you are using prepress registration rule that you cut out (after
registration) and a splinter of it remains.
So, there you have it.