by Scott Sabreen, president, The Sabreen Group
Micro-printing is a technique that creates a faint line composed of very fine text. Printers and lasers are used. This text is only legible through magnification. Less than 1 point font size and smaller is typical.
Guilloche are complex geometric patterns that consist of numerous interwoven fine lines. Because each pattern is uniquely generated, exact reproduction is nearly impossible.
Holograms display images that shift when the viewing angle is changed. They can be embedded or laminated.
Optically variable devices (OVDs) consist of a holographic film or layers applied to a cardÂ’s construction. Holograms may have 3D effects, color changing properties, etc.
Color shifting ink shows different colors as the viewing angle changes. The effect is impossible to reproduce with scanners and copiers.
Taggants are chemical or physical markers added to materials to allow various forms of testing. Physical taggants can take many forms but typically are microscopic in size, included at low levels and simple to detect.
Ultraviolet (UV) inks are invisible in normal light but glow brightly when exposed to black light.
Hidden images are mathematically buried in the printed card and can be viewed with a validator lens. Because of the fine detail used to generate the hidden images, they cannot be scanned, copied or reproduced.
An Optical Variable Device (OVD) is an iridescent image that exhibits various optical effects, such as movement or color changes. OVDs are based on diffractive optical structures. This gives the appearance of different patterns, colors and designs depending on the amount of light striking the OVD and the angle at which the OVD is viewed.
Intaglio printing is a technique that produces a raised tactile relief (a tactile feature) that also can be recognized under oblique light.
