Are you using Print Booklet to print to PDF? If so, check the default settings on the PDF Printer. They're probably set to convert to RGB.
That's the thing, though: it's not. I'm using the exact same profile to Print Booklet as I use to export. Everywhere I look under the settings it's set to CMYK:
Output -> Colour: Composite CMYK
Inks: Cyan, Magenta, Yellow and Black
Graphics -> Images: default to Optimised Subsampling, whatever that means, but changing that to anything else in the list doesn't fix the problem
Colour Management: Print: Document: Profile (U.S. Web Coated (SWOP) v2)
Color Handling: Let InDesign determine colours (the other option being to let PostSript determine them; doesn't fix the problem if I swap that)
Printer Profile: Document CMYK - U.S. Web Coated (SWOP) v2
Output Colour: Composite CMYK (Preserve CMYK Numbers checkbox checked)
There's nowhere I can see that RGB is selected as an option. Am I missing something?
Are you using one of the PDF Export Presets? If so, which one?
No, a custom one. Mostly based on the High Quality Print settings but with a few changes, most notably:
Output: Colour Conversion: convert to destination (Destination: US Web Coated SWOP v2)
Also some stuff with the bleed/crop marks and image compression of monochrome images by ZIP instead of CCITT Group 4, but that's irrelevant, so far as I can tell.
Can you share the file or a dummy one that shows the problem?
This is not about the settings you have in InDesign or the Print Booklet dialog, it's about the Adobe PDF virtual printer properties (the driver settings). By default, the PDF printer uses smallest file size as the preset, I think (I changed my default years ago), so you must either change the settings in the printer proerties through Windows, or enter the driver from the print setup dialog after accessing it from Print Booklet.
I'd prefer not to (first and foremost, client-supplied file. Also the original is pushing 30megs) but I can do some print screening:
http://bloogum.net/temp/cmykissue.jpg Top is the original file supplied by the client, completely CMYK. Bottom is the resulting PDF when I print the booklet, converting all the images to RGB output.
http://bloogum.net/temp/settings.jpg And my settings.
As I said, you need to go one step deeper and press the setup button to access the driver settings....
GOT IT thank you so much! It must have updated its own driver or something, because I've had that defaulting to my own settings for years, too, and I only just realised it's been stuffing things up with this latest one. Ugh. But yes, it had set itself to 'Standard', now back to my custom settings and we're away.
THANK YOU this has been irritating me for hours!
Yeah that reply came up just as I was typing mine, sorry, missed that ;P
Did you do a reinstall of Acrobat, by chance? I always forget to fix the printer defaults after that until I get an RGB file.
That could be it. There was a 3-month period not long ago where I wasn't using that computer (work computer) and ANYTHING COULD HAVE HAPPENED.