Some paint describe themselves as "enamel paint", however, 1) they're just a high-quality oil paint, and 2) any paint can describe itself as "enamel" because there's no objective standard that sets it apart from other oil paints.
TODO — read this long and really interesting educational piece on different model paints.
TODO — read about adding pigment to epoxy [1] [2] [3] [4] [5]
TODO — The paint coatings used to protect bridges might prove useful. [1] [2]