The thing that ticks me about Pantone, Behr, Sherman
Williams or
whatever is that they're proprietary systems and RGB is the "Open
Source" solution, going back to basic principles and should be
communicable to the proprietary mixer systems, but not the reverse.
RGB isn't enough - not everyone's visual system's response can be
modeled accurately by RGB. (Some people have colour receptors whose
response peaks are at nonstandard frequencies; a few people even have
more than three different colour receptors.)
The only really comprehensive way would be to give the full
frequency-vs-albedo curve.
/~\ The ASCII der Mouse
\ / Ribbon Campaign
X Against HTML mouse(a)rodents.montreal.qc.ca
/ \ Email! 7D C8 61 52 5D E7 2D 39 4E F1 31 3E E8 B3 27 4B