Brent
There is someone on this forum who is a paint expert , I hope he will chip in before too long.
Failing that, modern measuring instruments can very accurately assess the exact make up of the colour , by giving the amount of the 3 basic shades (cyan , magenta and ? yellow) present in that particular colour. This will enable an automotive paint supplier to mix up an exact match for you. (Remember that paint will look darker when wet in the can , as opposed to the dried pain film on the car)