I realize I made a similar post, but the responses did not answer my question (perhaps my question was not specific enough then).
Today the printer said that all my images would need to be in the CMYK color space, because they do offset printing and it is required.
Edit: I just asked my printer again what I would need to do. Here is the message he left me,
How would you respond to his message? I obviously don't know the answers to what he wants to know."you have to find out if LYX has to be able to import CMYK image files + convert text file to CMYK PDF.
No offset printer will be able to print with RGB PDF file, … so the only steps you should need to research is whether if LYX can provide CMYK offset pdf. "
I used the [cmyk} xcolor package in the preamble and then viewed the resulting pdf, but I couldn't notice any difference in that pdf compared to my original. So, I'm not sure if that's the sort of thing that he's after...based on how the pdf looked after entering that xcolor command in the preamble, I definitely have no idea if the JPGs embedded in the document were converted to the CMYK color space, or if just the text was converted, or if nothing was converted.
Edit:
I'm not sure if the printer just wants me to change the lyx pdf to a CMYK output or if he wants me to make sure each individual image is rendered as CMYK and wants me to change the lyx pdf to a CMYK output. I'll ask.
