Converting PDF to CMYK (with identify recognizing CMYK)

Question

I am having much trouble to get ImageMagick\'s identify to, well, identify a PDF as CMYK.

Essentially, let\'s say I\'m building this file, test.t

Answer 1

Revisiting the CMYK conversion with PDF/X-3 again as I have another print job in the queue made me find out the following:

If you only need CMYK, avoid X-3. It does not support transparency (https://en.wikipedia.org/wiki/PDF/X) and the cyan tinted image you will get is neither satisfying nor will it actually conform to any standard. If you have alpha, opacity, gradients do not convert to PDF/X-3 if not absolutely needed by your print shop.

If you do need pdf/X you will need to rasterize and go for X-3. There is no X-4 on Linux / free software products that I know of in the "well known tool chain" (imagemagick, inkscape, gimp etc. )

I am however still fighting with defined rich black, f.ex. 60%C, 60%M, 40%Y, 100%K - a rather typical standard for print shops here. Whenever I set this in inkscape it will be gone as soon as export (to RGB; a cairo limitation)

Still, this is what seems to get me close to what they'd expect:

#!/bin/bash

# possibly ps2ps2 for keeping fonts?
pdf2ps -sOutputFile=- "$1" | gs \
-dPDFX \
-dBATCH \
-dNOPAUSE \
-dNOOUTERSAVE \
-dPDFSETTINGS=/prepress \
-dCompatibilityLevel=1.4 \
-sDEVICE=pdfwrite \
-sColorConversionStrategy=CMYK \
-sProcessColorModel=DeviceCMYK \
-dHaveTransparency=false \
-sOutputFile="${1%%.pdf}_X-3.pdf" \
PDFX_def.ps \
-

Any insights on a true CMYK creation to CMYK-PDF output workflow are still very welcome. Scribus is no real solution as it has lots of problems importing inkscape SVGs correctly.. Other than that, scribus does a decent job creating CMYK-PDFs.