I'v been in NCRS near the start and have seen every shade of Blue,copper,and sliver Corvette. The number one differance of each was do to the size of the Metallic particles used. C1 and C2 used a very fine (small) metallic particle that is hard to see.But the big differance is the color shade! useing the wrong particles by the painter, not useing the right metallic particles.I can safely say ever person has seen this over and over, were two blue Corvettes have a different shade. Any one knowing when they are looking at the right color should always do as I do, and get the formula from the person haveing the right shad for a possible future car.When My 57 Cascade Green was on the front cover of the Restorer in 1985 I had calls from a dozen people around the world for the formula and up till then I never saw another one.So I'm just saying that any one going Metallic should warn thier painter first.