The automotive industry doesn't even call it paint or enamel. Now its "a vehicle coating system."

Most automakers now claim to use multi-layer finishes, but they're secretive about how they're actually put on. Often there's a "subcoat" that is basically a surface preparation to make the rest of the stuff stick, followed perhaps by a "primer coat" (strangely sometimes still called that) that's supposed to provide a "barrier corrosion protection," maybe followed by a "sub-coatin" to provide adhesion to the anticorrosion layer, then an "undercoat" that often appears to do little except set a neutral color, then a "color coat" of course, followed by one or more layers of "clearcoat" to make everything shiny. Some claim a "hardcoat" between color and clearcoat.

In Automotive Engineering magazine (SAE International) one maker not too long ago was claiming a "17 layer finish" but I think they must have been counting the "do-overs."

John