Trapping generally refers to overlapping
colors that are adjacent to one another and occurs with all designs. Even with
the best presses, there tends to be some movement from color to color when
trying to register them without leaving a white gap between them. While newer
presses may claim to be able to register color to color with very little trap
being applied, it is just good sense to make some allowance to help make the
printers job easier and the customers' satisfaction greater. Having said this, if
you apply too much trap between medium hue colors they can create a darker line
where they meet. The trick to what works best for you and your equipment is to
carry out regular finger printing to help determine the sort of registration
that can be held and is particularly important on older equipment as bearings
and gears begin to wear.
Having an experienced prepress operator that has
plenty of separation experience can make the art of trapping look easy, but
even with newer software that can be used to apply trapping between colors
automatically there is a great skill to being able to help make any job either
easy to print, or a nightmare if care is not taken when applying trapping.
Always try to explain to your prepress house/customer what you need to
produce a good print for them and do not be afraid to adjust your files to what
you need and not what someone else thinks you need. This can be particularly
difficult when a customer is more
accustomed to offset printing where little or no trapping is often the norm.