How to convert a PDF's Process Black to spot color

[patty_fagan]

We have been asked to build InDesign templates for a two-PMS-color math book. The design calls for two PMS colors: a dark blue for most text and red highlights.

Because our Math plug-in doesn't work easily with PMS colors (it defaults to Process black), we hope to create all the “blue” text in Process Black. The press PDFs will have two inks: Process Black and PMS red. On press they will print the black plate in our blue PMS color.

This plan works on press, but for non-press use, we also want the PDFs to visually match the blue and red printed book. Ideally we would convert the Black Process ink to a blue spot but I'm not sure if this can be done.

Question 1: Does anyone know of a way to convert Process Black in a PDF to a spot color? Pitstop can convert spot to process, but we want the reverse.

Question 2 (which I may also post in the InDesign forum) Do you know of a way to redefine (or alias?) the indesign black swatch so that it functions as a spot color?

[Dave Merchant]

1 - yes, you can do this with Preflight in Acrobat Pro, but it's not on the default set of fixups.

• Open Preflight, select "Single fixups" - the wrench icon
• Options > Create New Preflight Fixup
• Give it a name (e.g. "process black to spot")
• Choose the Color category in the upper right
• Choose 'Convert to spot color' in the upper left
• Define the source parameters in the main panel (in your case, CMYK%, 0-0-0-100 with tolerance 0)
• Define the spot color to change this color into, and the alternative space for rendering (i.e. your blue color)
• If you wish, add a check to limit the conversion to certain things (e.g. text, vectors, etc.)

Click OK to save the fixup, then click FIX to apply it. To verify the result, use the Output Preview dialog in Acrobat.

[patty_fagan · Accepted solution]

Thank you so much! We will run a test next week.

[RTECK Agency LLC]

To go a step further, is there a way to include images in this conversion?

I have PDFs that get sent to the printer as Process Black only (grayscale), and the printer applies the spot color on press. The client likes to see their proofs in a simulation of the PMS. The PDFs contain images and text and when I followed the instructions here everthing converts except for the images. Any suggestions?

[Bo_LeBeau]

To convert everything in the PDF to black only it is easier to just use "Convert Colors" instead of messing with Fixups.

In Acrobat Pro go the the Advanced menu, Print Production, Convert Colors.  (the menus may change depending on your version of Acrobat Pro)

In the dialog under Output Intent, check the box for Convert Colors to Output Intent, and choose a Grayscale profile from the drop down list (something like Dot Gain 10%) and click OK.

In the screenshot you can see a PDF that has CMYK and 5 Spot Colors. They will all be converted to Grayscale only (no other plates to worry about)

Click the image in this post to see an enlarged view

[RTECK Agency LLC]

I'm starting with PDFs that are black only and I need them to convert to PANTONE 174 C for proofing, which is why I'm so interested in this thread. I've tried the steps outlined above and everything converts to 174 except for the grayscale images. Is there another step that can be added to the coversion so the images have the SPOT color applied as well?

[Bo_LeBeau]

I misunderstood your question. I thought you had a PDF that was already all Spot Color and needed a quick way to convert everything to Grayscale to be able to send to your printer.

What application are you creating the original document in and how are you creating the PDF?

[RTECK Agency LLC]

No worries. The original doc is supplied to me as an InDesign Document. I then create an X1a compliant PDF straight out of InDesign. The PDF is black only and needs to be PANTONE 174 C, but only for proofing. When approved the original black only PDF goes to the printer and they apply the spot.

Thanks for responding, and thanks for the help!

[Dave Merchant]

Unfortunately it's not within the current capabilities of Preflight to convert colors within bitmap image page objects. The conversion fixups only inspect items which have their colors defined within the PDF content stream (vector shapes, fills and text). Acrobat's Ink Manager feature cannot alias a process K plate into a spot color, it can only go the other way.