Thanks Jimi

The prints are pretty straightforward at this stage e.g. Business Cards, without bit maps. When it gets more complicated we may well move to a different printer.

I think what I'm learning here (and I'm not a neophyte in computer graphics, but I am when it comes to printing CMYK) is that it's an even more inexact science than printing usually is, as we're dealing standards for incomparable mediums that have no direct cross-relationship.

I'm figuring that if the printed output looks right and that it is quite different to what the PDF looks like on screen, then the CMYK information is in the PDF file and that I'm likely to get the same result if I send that PDF file to the printer

A different, but related question. If I can print RGB from my CMYK printer and it near enough matches the RGB on screen, why can't professional printers do that?

Thanks
Patrick