Artificial Watermark
A printed pattern or symbol using inks with no tonal value (usually off-white, white opaque, transparent, reflective or oil-based inks) that only appears when the substrate is tilted to normal light and/or transmitted light.
Blind Embossing
A colorless relief image or raised impression made without use of inks or foils.
Copy-Evident Background
A pattern designed into the printed background which becomes visible when photocopied or scanned.
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.
Dropout
An image visible under normal lighting conditions, but disappears under an alternate light source.
Duplex Patterns
A design made up of an interlocking pattern or irregular shapes, printed on opposite sides of the substrate. The images when viewed with transmitted light, creates one complete and registered image.
Embossing
The process of creating a raised image into the substrates surface, using either a set of male/female dies or engraved plates/cylinders and magnetic flexible dies under high pressure. Tactile elements can also be created using specialty inks and/or thick layers of inks to create a raised image.
Guilloche Pattern
An intricate pattern of overlapping, continuous colored lines.
Latent Image
An image or pattern created with raised lines placed at a right angle (90 degrees) from the background, so that when viewed at an oblique angle the image is visible through light and shadow effects.
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.
