"Jo [actually Alan] Taylor" writes:
You are correct in saying I don't think it's as simple as that... but
not for the right reasons.

a. Cyan, Magenta and Yellow are not paint primary colours but transparent
printers' ink primaries and rely on overlay not pre-mixing for the effect.
Paint primaries are red, blue and yellow and, in emulsion paint, are opaque.

Alan Taylor made this same argument nearly a month ago here.
Eventually he made some example images available on the Web;
unfortunately viewing them required one to be a member of the Yahoo
BritArt group. I have rehosted them with his commentary; see
http://www.alumni.caltech.edu/~mjackson/color.html. He's got some
further words that should accompany the images, but I don't have access
to my alumni account from work so will leave it to him to make any
additional points here.

--
Mark Jackson - http://www.alumni.caltech.edu/~mjackson
Learning without thinking is useless. Thinking without
learning is dangerous. - Confucius