Abstract: An authenticatable product comprising a non-opaque latent image layer of anisotropic polymer material having background optical properties with a given preferred direction of anisotropy and a given proportion of crystallinity, the latent image layer being treated so as to include: a first localized modification in the latent image layer being associated with a first latent image; and a second localized modification in the latent image layer being associated with a second latent image such that, when viewed directly, the first latent image and the second latent image are indistinguishable from the remainder of the latent image layer and, under polarized visualization, a maximum contrast between the first latent image and the remainder of the latent image layer is actualized at a different orientation of polarized visualization than a maximum contrast between the second latent image and the remainder of the latent image layer.