Why is InDesign SO much better than Quark?

[David Kunkel]

The thing to check with Quark files and your trapping problems:
Quark has a default background of "White" in its "Picture Boxes".
So the picture is sitting on a white background.
When you run those files through a trapping application
the picture just sits there
while the White background of the Picture Box (underneath the picture)
"Spreads" out to trap with the surrounding objects
(producing the "White Line").
Always - set Quarks Picture Box "fill" to "None".

MSD

You can instruct users to change Quark's default fill from white to "None" (or 0% black) in the Preferences/Tools section.