Need help/answers on PDF color seperation

Question

Using the following process:

1. A PDF is been created by PDFCreator, when a user prints something to the virtual printer
2. The PDF gets further processed with integrated VBScript handler and passed over to JAVA which does some processing with the PDF content
3. In the middle of the process an external application is called with the PDF that adds black text and graphics to the PDF
4. The PDFs are collected and once a week handed over to a print shop that uses a plate for each CMYK

The problem is: the print shop needs a color seperated CMYK PDF, but the added black text & graphics from the external app should be the only content on the K plane (because we want to make a special print effect). All other content which has been printed via PDFCreator should be on CMY plates only, so black must be emulated with those colors.

At the moment we are manually braking the process before calling the external application and seperate the colors via Adobe Creator Pro, but that is no future option because the whole process should work automated.

So basicly I need a way to convert the CMYK PDFCreator PDF to a CMY version only so the external app can throw in as many black K content as needed.

Is the PDF conversion the right direction I'm heading to? Is there any way w/ ghostscript how this can be done? I read the gs documentation but got nowhere as I only saw RGB to CMYK conversion but no CMYK to CMY with empty B...

Answer 1

I believe that PDFCreator is simply a wrapper around ghostscript, so you may have some joy on the ghostscript mailing lists. It seems that gs does support some printers that just ouput CMY so this functionality is likely to be available in there.

Wouldn't you be better off using a new separation called Black? Can't the print shop handle that?