warning in PDF/X preflight about separated black although no black is used at all

[Asterixx]

Hello, 

when doing a preflight of a X-1a document in Acrobat Pro with the PDFX-ready profiles, I sometimes get the warning that black could be reseperated. Well, it even appears when I don't use black at all :). 

I noticed this error long time ago and never thought about it again, but now I work again with illustrations where I deliver X-1a (or later also) so I remembered this and indeed the error is still there. 

Interesting: the warning only appears when I use a shape and a contour overlapping. When the same two objects (just 1 line and 1 circle) don't overlap or I only have one of them in the document, then no warning appears. 

Seems the PDFX ready preflight checks whether colors are overlapping. But it does not depend on the overprint setting by the way. 

How can I understand this warning, did you experience it as well, and is this e.g. also known from other preflight solutions as Pitstop / Callas (which I don't own) ?

[creative explorer]

@Asterixx The most likely cause is related to how the PDF renderer and the preflight profile handle complex, overlapping color objects and the required flattening for PDF/X-1a. If you know for sure there is no black being used, you can ingore it. If you wanted, and since Pitstop / Callas (which you don't own)— you could use Acrobat's Preflight Fixup

[Asterixx]

thank you very much. I just tried hard to reproduce it 🙂 because the error was not always there. 

I seems to be related either if there are only shapes / shapes+strokes and even more how dark the colors are. So indeed I can even use black as stroke but only with a light color (like light blue) in the fill, then there is no error. But when I choose a dark color for the fill, the "black seems reseparated" in both cases: black + dark fill and any dark stroke color + dark fill.

By the way the normal Adobe preflight for X-1a has "no problems found" and ok as result, but I was not sure if the Acrobat 9 preflight is a bit old. Can I still trust the X-1a and X-4 preflight of Acrobat 9 ? (or prefer the newer PDFX-ready profiles for the preflight)

Ok, and even another question as I was working so long on this issue the last hours. When I export a X-4 and check in Acrobat Preflight, in both cases (Adobe preflight and PDFX-ready) I get the two errors:

- OCCD has no BaseState entry
- OCCD has not empty Order entry 

Those I can probably also ignore?