Hi David,
In choosing 'white' as my border color I am assuming (according to the feature description in the help files), the 'white' is essentially the 'paper white', is this correct?
I'm pretty sure that is the case, I can't see that it could be anything else. The only possible exception is if your ink set includes a gloss optimiser but from what I can see on my prints, white is definitely paper white on borders.
Terry