Reply To: Spot colors for press

..  they had to uncheck 'overprint preview' in acrobat to create the postscript and the plates ..

How extremely odd.

“Overprint preview” is a screen-only function. Checking and unchecking this will draw a certain PDF using different algorithms, but the PDF itself *will not be changed*. It certainly should have *no influence at all* on how a document is printed — that should be the same, no matter what the preview looks like.

(Unless these printers have very unusual procedures, like using the Print Screen button to produce their plates.)