Abstract: An anti-counterfeit feature for a multi-layer document or plastic laminated card is provided according to some embodiments. The laminated card can include an embedded layer including a radio frequency radiation absorbing or deflecting material. The card can be authenticated by detecting an absence or a modification of a radio frequency signal due to the card interfering with a radiation source. The laminated card can also include a pattern of perforations passing partially or fully through one or more layers of the card so as to produce an effect similar to a watermark in the assembled laminated card by giving the card a modified transparency in a pattern associated with the pattern of perforations. The card can be authenticated by observing a pattern of light through the perforations.

Abstract: Laminate document include line screen patterns for authenticating the documents. The line screen patterns can hide information in the documents that can be revealed by a viewer. Print densities of the line screen patterns can be adjusted to compensate for effects associated with lamination. A built-in viewer can be spaced from the line patterns to shift image intensity or color through rapid cycles of moire interference with changes in viewing angle.