I'm working with a psd in PS in CMYK mode. After exporting a standard "High Quality Print" PDF, there is noticeable overall desaturation in the exported PDF. Why, if I am working in CMYK, and exporting in CMYK, is there a change?
I currently have "No Color Conversion" selected, should I convert it to something?
This is a common occurrence with CMYK PDFs (and other CMYK documents, on occasion) when viewed with tools that are oblivious to CMYK color spaces and try to interpret the image information as RGB. Even Bridge has this issue with thumbnails of CMYK PDFs. It's nothing to be concerned about. Acrobat and Photoshop understand CMYK information and know how to interpret it for an RGB output device (the monitor), so you see it correctly.
As a note, Preview is a notoriously unreliable way to view a press-ready PDF. It's not just the CMYK-to-Screen that's flaky. Bits of the PDF, like certain characters in a font or some images, may not render at all, even though they are there and will print fine.
As an addition to @AlanGilbertson answer:
For some reason there's a huge difference when saving or printing a PDF document from Ai CS.
To see what I'm talking about:
The result is that the saved file will still have the plain colors and the printed file will have for example cyan build out of ~78% cyan and ~28% magenta.
Sometimes you have to make Adobe as your default printer before saving. That has worked for me in the past.
