- Apologies. I didn't mean to be an alarmist with that last post on
Knowing that raw stock has a limited shelf-life is useful information
in itself. Knowing exactly when it will go bad is another thing
A technical rep at Handschy recently told me that ink has a shelf-life
of one year. This goes against the old wisdom that the older an ink is
the better it gets. I wouldn't have believed him until I discovered
that some of the newer formulated inks seem to go bad from the inside
out, not from the top of the can downward but from the bottom up. This
completely ruined a job because the ink was notoriously stiff in the
first place and we weren't attentive to the fact that the abnormal
stiffness at the bottom third of the can was due to loss of carrier.
Same with rollers. A friend recently gave me a durometer for measuring
the hardness of printing rollers. Now I know that my rollers are
increasing in hardness almost a point every one and half to two
months. How useful is this to know? My roller rep says that when they
hit Shore A 50° they will fail to split the ink altogether.
So do I throw the rollers out when they hit Shore A 49°? Do I throw
the ink or the raw photopolymer plates out when they hit the 364 day
No, I'll most likely use the rollers, the ink, and the plates until
problems BEGIN to occur that can't be blamed on other factors. Armed
with a bit of knowledge about materials degradation, however, when
certain problems do start occurring, I will at least have some clue as
to what the cause may be.