The pdfcolour utility allows one to split a PDF file apart to give two separate PDFs, one containing the colour pages and the other containing the B&W pages. That way, one can easily print the B&W pages on a faster, cheaper printer and reassemble the document by hand.
Download the pdfcolour-1.2.tgz file.
Extract it using tar -xzf pdfcolour-1.2.tgz
Recompile if necessary using the command “make”.
Run on a PDF with splitcolour input.pdf bw.pdf colour.pdf
For our American friends, this program will split a PDF into separate color and black/white files.