Exporting an Indesign file to PDF with duotone images

Forum|Forum|8 months ago
August 1, 2025
4 replies
479 views

Hello,

I’m working with an InDesign file that contains duotone images—one 100% black channel and one additional Pantone spot color (Pantone Black Process).

In previous versions of InDesign, exporting to PDF for print preserved only the Black and Pantone plates, without generating any CMY separations. Since updating to the latest version, the exported PDF now includes CMY plates as well, which shouldn’t happen...!

Could you help me understand what’s causing this and how to ensure only the Black and Pantone channels are used in the PDF output?

Thank you,

F.

Print

BobLevine

Community Expert

I haven't used spot colors in quite a while but I have no recollection of any PDF export excluding empty plates. Just tell the printer the file is black plus one spot and to disregard the empty CMY plates.

BTW, InDesign always uses registration for crop and bleed marks so that will certainly generate all plates.

E

Eugene Tyson

Community Expert

BTW, InDesign always uses registration for crop and bleed marks so that will certainly generate all plates.

By @BobLevine

I've always had an ick and about this. The Registration colour should only use the colours used in the artwork. It shouldn't include CMY if it's not used the layout.

I know that's how it works - I'm just saying it shouldn't, technically.

rob day

Community Expert

In previous versions of InDesign, exporting to PDF for print preserved only the Black and Pantone plates

Hi @fresbee55 , I’m still using InDesign 16, and when there is a spot plate the Export includes the process CMYK plates along with the spot plate. When they print separations, your printer can choose to emit just the process Black and Spot plates.

Brad @ Roaring Mouse

Community Expert

Same here. I always expect the CMY plates as well. I just did a test with every version from CC2020 thru now and they all exported the same. Did the OP maybe make the "Black" a spot colour?