What kind of car do you have? I mean, unless you have a '53 Kaiser Darrin you are bound to find a photo of "your" car what ever color you want. Now, it may not be the EXACT color, but the representation of the color on your monitor isn't going to be right anyway. So, a "light blue met" is going to cover a heck of a lot of different light blue metallics.
The truth to the matter is, most every color has been used before and you can get a good idea by looking at theirs.