It's not something like
this is it?
( Druid, Mon 6 Jul 2009, 23:42, archived)

I don't think so
it didn't refuse to scan it

something to do with tiny variations in the print matrix, perhaps if you scanned it at exactly the dpi it was printed at and lined it up perfectly it wouldn't show
( VampireMonkeyOnSpeed a super sexy sexual sex terrorist sex, Mon 6 Jul 2009, 23:45, archived)