I've been having an issue what I had already fixed. Customer is printing a Imposed 2x1 Step and repeat book with crop marks preparing with Adobe. File is 400 B/W pages and 50 color pages. They generate a PDF document and import file on their rip (Fiery). When they proccess the file all pages are counted in color so customer claim because pricing is different between color and b/w pages. Some time ago, I fixed the issue creating a Spot color substitution with the name of All (CMY:0 K:100) however I do not undestand why this setting does not work on certain rip so I wonder If there are a way to change this crop marks to pure black on Adobe applications.
I'm printing on a Xerox iGen4 with Fiery controller.