An authenticatable article can comprise a polymer layer comprising a first taggant, and a second taggant disposed adjacent to the first taggant. The relative relationship of the first taggant and the second taggant can be such that at least one of the first taggant and the second taggant can cause an alteration in an emission from the other of the first taggant and the second taggant. One method of authenticating an article comprises illuminating an article and determining if an altered emission is within a selected emission range. The article comprises a polymer layer and a coating disposed on a side of the polymer layer. The polymer layer comprises a first taggant, and the coating causes a predetermined alteration in an emission from the taggant to form the altered emission.