Color managing in PDF for printing

[serenab9101952]

Hello,
I'm sorry if this question comes across as a bit stupid but I can't seem to solve this problem and the printer has not been helpful.
I need to export a PDF for offset printing (it has to be PDF/x-1a:2001); the artwork will be printed on a color newspaper.

I have a psd file with lots of photographic layers; vector smart objects, layer masks, etc.; working space is RGB.
If I change this via Image --> Mode, it says "Changing modes will discard some adjustment layers; change mode anyway?" ; and then proceeds to rasterize some layers if I check ok.

The color changes dramatically to a much darker shade. "Proof Colors" does not change the on screen appearance anyway.

Should I convert it before exporting? Or just manage colors in the save dialog box?

And when there, should I “Use Proof Setup: Working CMYK” and  “Embed color profile…”?
And also: should I Convert to Destination or allow “No Conversion”?

What's the best thing I can do in order to get the best output of the colors?

Thank you so much, looking forward for your response.

[rob day]

PDF/X-1a forces all color to CMYK with no profile, so you don't have to convert your RGB version to CMYK, the conversion will happen when you Save As to PDF.

You can use Proof Colors to preview the conversion to CMYK without actually making the conversion. Set the Proof Setup to Working CMYK and choose Proof Colors. Open Color Settings, set your CMYK working space to your newsprint profile, with Use Black Point Compensation checked, and Relative Colormetric as the Intent. Something like this:

Save As to PDF/X-1a. The Output panel's Destination should be to your newsprint profile:

In AcrobatPro view via Output Preview:

[D Fosse]

serenab9101952  wrote

"Changing modes will discard some adjustment layers; change mode anyway?"

You need to pay attention to this. You must flatten all files first! Adjustment layers made in RGB will make no sense in CMYK; so they are just thrown away.

This shouldn't be a problem if you keep your master file as is. Do this on a copy and export from that.

[rob day]

You must flatten all files first!

PDF/X-1a doesn't allow transparency so the flattening will happen with the Save As to PDF/X-1a:

[D Fosse]

Yes, and that's my point exactly: This automatic flattening will discard RGB adjustment layers, not incorporate or merge them. That's why it's necessary to flatten beforehand.

[rob day]

It's understandable that you would assume that, but I'm not seeing a difference in the PDF numbers.

It looks to me like the flattening happens before the conversion to CMYK during the PDF export. If I export layered and flattened versions of the same RGB file to X-1a, the CMYK output values in AcrobatPro match.

Here the version on the left was layered, while the version on the right was flattened in PS.

Flattened version sampled

Layered version sampled.

[D Fosse]

Yes, you're right. The flattening that occurs on export to X1-a does indeed happen before the conversion into destination CMYK. I just tested it.

It's a straight mode change in Photoshop that triggers this warning, which does exactly what it says it will:

[rob day]

Similar questions come up over in the ID forum. If the conversion happened before the flattening, we wouldn't be able to place and properly CM layered RGB files when exporting to CMYK destinations.