CMYK image in a PDF is involuntarily converted to RGB when you send from Acrobat Pro DC to Photoshop for editing

Question

Hi,
When I send a CMYK image from Adobe Acrobat Pro DC to Photoshop CC 2014 to be edited, it opens up as RGB in Photoshop CC 2014. If I do the same with Adobe Acrobat XI on another machine, the image opens as CMYK, as it should normally do. As we had created the print-ready PDF in the first place, we know that the image is definitely CMYK and is properly opened in Photoshop if we use Adoba Acrobat Pro XI. We of course can go back to the original document and edit the linked image and re-export a new PDF. But on many occasions we need to do last minute corrections on images by editing them externally in Photoshop.
Best,
Refik Telhan

Answer 1

It's really necessary to know by which program you had created the PDF.
Here comes a test PDF for questions like yours, created by InDesign:
http://docs-hoffmann.de/riptest05072013.pdf
Different images:
sRGB, pRGB=ProphotoRGB, CMYK , all with individually embedded profile,
Grayscales: without embedded profiles, because InDesign doesn't embed gray profiles,
Lab: without profile, because Lab is automatically detected and not ambiguuos.
Of course, using so many different images in one PDF is useful only for tests.
An actual test:
Touch Up Object Grayscale and edit in Photoshop. There is no embedded profile
but the image is in PS detected as Grayscale. One has to assign a profile.
Re-imported in the doc, it is a Grayscale JPEG*, before it was a Grayscale ZIP.
In Acrobat 8 one can check the actual content of a PDF by
Advanced > Print Production > Preflight
In newer versions this is still available but somewhere else.
I'm using version 8, because I uninstalled X on purpose.
Best regards --Gernot Hoffmann
*Edited:
As far as I remember, there is no special code for Grayscale JPEGs, it's just a JPEG
with zeros in the Cb Cr channels ... like an R=G=B gray image.