[NTG-context] CMYK workflow. How to set and should I worry about

Colleagues I'm getting ready to send  a book to the  printers and in their blurb they state "/Ensure that you are using a CMYK workflow and export to PDF/X-1a:2001" . /I can set the pdf format using \setupbackend but I'm unsure as to what to do about CMYK workflow. The book has no colour pages so I'm not sure if I really need to worry about CMYK workflow. Could someone advise? Thanks and Best Wishes Keith McKay //