For those who don't know (and I'm no expert), the Pantone Matching System (PMS) provides color standards that are available in a printed book that you may find in a good art supply store. Because the PMS colors are STANDARD, by matching to these colors, it is easy to convey to printers, paint manufacturers, etc. what color you're really talking about.
The Pantone system does offer advantages -- an easily reproduced standard colour system, but you'll also find that you will have to approximate colours to some degree. There simply aren't enough Pantone colours to match everything precisely.
Stafford Swain noted in his CN colour study: it was kind of like using a ruler in which the lines weren't close enough together (or words to that effect).
-- Ian Cranstone Kanata, Ontario, Canada lamontc@nakina.net (note change: was lamontc@magi.com)