After ten years without an issue, our print shop has lately been having some problems with the separations that we've been sending. The only things that have changed recently are that I've been upgraded from CS5 to CS6 and the print shop installed new RIP software for their offset press. In a nutshell, the problem is that when I export a plate for a single spot color (in this case PMS Black), my guy at the print shop says the file is being read as CMYK. I've double checked that all inks other than the spot color are unchecked in the Ink Manager and then printed to a PDF, but he insists that he's getting four plates and that if he just prints the black plate it prints as a screen.
As part of my investigation into this, I tried an experiment. I created a page in InDesign on which I placed 2 boxes, one filled with a PMS Blue and the other with a process green. I then printed this to a PDF as separations with only the PMS blue ink selected. As expected, this produced a single page PDF showing the box in black with a page title of "Pantone Blue 071".
However, when I look at this PDF in Acrobat, the Ink Manager shows only CMYK channels and no PMS Blue. If I then export separations from Acrobat, it generates a 4 page PDF with 3 blank pages for C, M, and Y. The square which was filled with PMS Blue in the original InDesign file appears on the fourth (K) page. Still, the box appears as solid black and doesn't look like it should print as a screen. However, I don't see anything in the Acrobat properties or print dialog boxes that mentions the PMS Blue at all.
Can someone give me some insight as to exactly what's happening here so I can advise our print shop on a possible solution? As I said, for the last ten years I've simply separated a spot ink by unchecking all other inks in the Ink Manager. I've never had an issue with the resulting PDF, so this is the first time I've had to look this deeply into the process. For what it's worth, the offset press they're using is somewhat old and the new RIP software they instaled is a KODAK product, though I can't remember the name right now. I could find out if it'd be useful. Any help would be appreciated. Thanks in advance for any assistance!