Is there a program/software so I can scan my 51 chevy and try different colors on it before I really paint it?

I want to paint my 51 chevy and each and every day I go out driving I see a different color and try to imagine it on my 51, someone told me to bad there wasnt a way to let the computer change the color until you find the right one. so thats my question is there something out there that can do this ?? hope I made my question clear.Is there a program/software so I can scan my 51 chevy and try different colors on it before I really paint it?
I just did almost the same thing with Adobe photoshop... (I designed a graphic setup for my car...) You can cut specific colors, or fill whole areas with another... There are incredible tutorials out there for it too. Google the photoshop bible if you have any concerns on how to use it... Hope it helps!