Placed PDFs color error message

[DKMusic]

Hi, I'm getting the following error message in pre-flight:

"Placed pdf has objects of a color different to the document colorspace..."

How do I resolve this message? I will be placing approximately 600 PDFs, so even though AP tells me it will print fine, I want to get this right and avoid all the messages.

My PDFs are technically color, although they appear as just B/W. The blacks are what I guess is called “composite” black, not “true” black. I want my final document to be entirely B/W.

Should I perhaps change my color profile of my document to color, and only export in B/W? If so, how would I do that? Thanks!

[lacerto]

Obsolete.

[DKMusic]

Thank you! Here's one of the PDFs: https://www.dropbox.com/s/akjopo74z7ij4cg/Holy Holy Holy_gibc.pdf?dl=0

Could I just keep the project RGB or whatever it needs to be, and just export B/W in the final product?

I don't want to raster, as I don't want to move away from vector.

[lacerto]

Obsolete.

 

[lacerto]

Obsolete.

[DKMusic]

Indeed, I can export mono from Dorico. The problem is that I have some 3600 PDFs already created, probably all of them exported as "color." The thought of re-exporting each one in mono is a bit depressing.

The final export cannot be multi-color. The printer requires B/W, since the job is a single-color process.

Previously I think I just exported from InDesign as BW.

[lacerto]

Obsolete.

 

[DKMusic]

Thanks, that's a crucial bit of information.

I'm perhaps more inclined to leave it color, export it as color, and convert to greyscale in a 3rd-party app.

Some of these will be printed using extremely fine print processes and materials, and I need them to be as sharp as possible with no liabilities.

Thanks again!

[DKMusic]

Hold on though... why can't AP deal with the conversion? The rest of the error message says "The PDF will still pass through."

The export looked fine to me. Am I still playing with fire?

[lacerto]

Obsolete.

[lacerto]

Obsolete.

[DKMusic]

2 minutes ago, Lagarto said:

I think that this is the problem: RGB will be passed through even if you export specifying grayscale mode (and force conversion of image color space). But I'd be happy to proved wrong -- I have not examined this extensively.

Well... indeed. I checked the exported PDF, and it is indeed color. Ok, it seems in the long run I might in fact want to gradually re-export my individual PDFs as mono. Either that, or convert at the end. Thanks again.