Similar to fibers, planchettes are added directly to paper. Planchettes are normally produced in a geometric shape, and can be a carrier for such things as Taggants. Planchettes can also be simulated by printing directly on the substrate.


A watermark is a recognizable image or pattern in paper or plastic cards that appears as various shades of lightness/darkness when viewed by transmitted light (or when viewed by reflected light, atop a dark background), created by thickness and density variations in the paper or plastic cards. There are two main types of watermark, the…

Deliberate Error

An intentional printing mistake known only to the manufacturer and inspection officials. Typically, seen as a single event in a repeating sequence, in an attempt to trip-up criminals who try to recreate the image.

Line Screen Modulation

A method of digitizing halftone images, creating irregular spacing between lines or dots. When scanned or copied using normal frequencies the scanned image reveals a moiré pattern. Can be used in combination with a lens or filter to reveal a hidden image.

Metameric Colors

Two colors appear similar under normal lighting conditions, but because of differences in spectral/chemical composition, will appear dramatically different when viewed with a filter or differing light sources.


An extremely small line of text characters, symbols or images, indiscernible to the naked eye, printed at high resolution beyond the capabilities of desktop printers or scanners. This feature is often hidden in background design of vital records or as a signature line on checks and may contain intentional mistakes.