Glossary

A method of making copy-evident and tamper-resistant patterns in the background of a document. Normally these are invisible to the naked eye, but become obvious when the document is photocopied. Typically, they spell out ‘void’, ‘copy’, or ‘invalid’. See also Big dot little dot.

Refers to holograms where the thickness of the recording material is much larger than the wavelength of light used for recording. One of the most common types of hologram (together with surface relief holograms), volume holograms are mass-produced through optical copying of a master hologram onto photopolymer materials, so they retain more of the optical properties of the master than the mechanical, surface relief process. This allows them to be used for classical holograms which are fully 3D images, displaying depth and both vertical and horizontal parallax. Volume holograms are either monochromatic or two-colour, with a distinctly different appearance to rainbow holograms, which are based on diffraction.

An image in paper produced by varying the thickness and density of the paper mass during paper production. These variations form a discernible image that can be viewed when holding the paper up to the light. Used as a security feature on most banknotes.

A type of marker directly embedded within video, audio or print content, which is imperceptible to humans but readable by computers.Typically used to identify ownership of copyright and authenticate a genuine article.

A part of the production process of many security papers that uses pressure through a wire mesh to form designs or patterns by varying the thickness of the paper.

A photonic watermark for banknotes, developed by combining a invisible photonic printing with a translucent and ultra-thin magnetic-responsive photonic display film.

A property of electromagnetic radiation that denotes the distance between waves of light.

A mathematical means for performing a signal analysis when signal frequency varies over time.

A category of electronic devices that can be worn as accessories, embedded in clothing, implanted in the user’s body, or even tattooed on the skin.

A continous roll of flexible material, usually paper, foil, film or laminate in a roll form.

Involves the feeding of a continuous roll (or web) of paper through the printing press. Web-fed offset lithography (as opposed to sheet-fed offset) is the predominant print process for tax stamps and other security labels.

The application of a coating of wet glue to a dry substrate before it is attached to an item. This is the main way of applying tax stamps to products.

An indirect lithographic printing process where a flat printing plate prints onto a rubber blanket that transfers the image onto the paper. The printing plate must be moistened with water before it is inked, with the water adhering to the non-image area.

A paper-embedded security thread surfacing at regular intervals in a document and full visible when viewed in transmission.

A device comprising gratings of less than the wavelength of visible light (ie. below 400nm). Can be produced by embossing and displays unique colour effects depending on the device’s plane of rotation.

Zero trust assumes there is no implicit trust granted to assets or user accounts based solely on their physical or network location (ie. local area networks versus the internet) or based on asset ownership (enterprise or personally owned).