Abstract: The present invention provides improved spectral signature strategies for use to confirm the authenticity of a substrate and associated documentation.

Abstract: The present invention provides spectral code strategies that allow spectral codes to be accurately and consistently deployed in a wide range of substrates and background situations. The present invention uses taggant particles with a multilayer structure that is able to produce a strong, consistent spectral signal that is resistant to background noise effects. The spectral output can be read remotely from a distance using multispectral, particularly hyperspectral, imaging techniques.

Abstract: A spectrally responsive transfer system, comprising a taggant system comprising taggants exhibiting spectral characteristics in response to at least one illumination; a spectral code associated with the spectral characteristics; a coded transfer film releasably supported on a carrier allowing one or more portions of the transfer film to be selectively transferred from the carrier to a substrate to form spectrally coded indicia on the substrate; the transfer film comprising a spectral ink layer incorporating the taggant system and releasably coupled to the carrier; the transfer film also incorporating a metal foil layer over the spectral ink layer such that the metal foil layer overlies the spectral ink layer and such that the metal foil layer underlies the at least one spectral ink layer when the one or more, selectively transferred portions of the transfer film are transferred from the carrier onto the substrate.