Glossary

The application of a unique identifier to each unit in a lot or batch. The identifiers are numbers but might be printed as alphanumerics or barcodes or might be embedded in a chip activated by radio frequency (RFID). The numbers may be sequential or randomly generated; what is important is that the same number should not be used twice.

A printing press that requires sheets (as opposed to continuous rolls or webs) to be fed into the press prior to printing.

A coating mixture applied to paper or other substrate to improve printing or surface properties.

A plastic card with a built-in microprocessor, used typically for electronic processes such as financial transactions and personal identification.

A cellular (or mobile) telephone with an integrated computer, camera, and other features not originally associated with a mobile phone.

the fraudulent practice of sending text messages purporting to be from reputable companies in order to induce individuals to reveal personal information, such as passwords or credit card numbers.

The illegal transportation of objects, substances, information or people across an international border, in violation of applicable laws or other regulations, often to avoid taxation.

An advanced Raman spectroscopy technique used to analyse chemical compositions beneath the surface of a sample without needing to physically cut or otherwise disturb it. In traditional Raman spectroscopy, the laser light and detector are aligned directly on the sample surface, which only provides surface-level information. SORS, however, works by offsetting the detector to capture Raman signals from deeper within the sample.

Produced by the mutual interference of a set of coherent wavefronts. Speckle patterns have been used in a variety of applications in microscopy, imaging, optical manipulation and document biometrics (or fingerprinting). They typically occur in diffuse reflections of monochromatic light such as laser light.

The study of the absorption and emission of light and other radiation by matter. Involves the splitting of light (or more precisely electromagnetic radiation) into its constituent wavelengths (a spectrum), which is done in much the same way as a prism splitting light into a rainbow of colours. More recently, the definition has been expanded to include the study of interactions between particles such as electrons, protons, and ions, as well as their interaction with other particles as a function of their collision energy.

A process employed in offset printing where colours are intentionally allowed to overlap on the transfer cylinder producing a gradated effect.

Spoofing involves faking one’s identity, and can be used for various attacks such as identity theft. Phishing is one such use of spoofing that attempts to steal somebody’s personal information or credentials by having them volunteer that information from a nefarious source that looks legitimate.

Any colour printed with its own ink, in contrast to process colour printing which uses four inks (cyan, magenta, yellow and black – or CMYK) to produce all other colours.

The suspension of fibre and other materials in water used to manufacture paper.

The material or base – eg. paper or film – on which an image is printed or a feature applied.

A mobile or web application that can provide multiple services including payment and financial transaction processing, effectively becoming an all-encompassing self-contained commerce and communication online platform that embraces many aspects of personal and commercial life.

Security features that are applied to the surface of a banknote or secure document (eg. foil stripes, foil or optically variable ink patches, iridescent coatings) as opposed to features that are created through combinations of printing techniques or features integrated into the substrate, such as threads, fibres and watermarks.

The most ubiquitous and popular type of hologram, mainly exhibiting a characteristic rainbow-coloured pattern. The details of the hologram image are recorded as an interference pattern on the surface (rather than through the volume) of the material. The value of surface relief holograms is that they can be mass-produced mechanically by embossing or casting a relief pattern or image into an inexpensive thermoplastic film or viscous coating on a film or paper.

The property of a banknote or secure document feature that can be felt, often made by means of intaglio printing.

Molecular or microscopic particle that can be organic or inorganic in composition and exhibit specific and unique physical, biological, chemical or spectroscopic properties. Added in very low concentration to substrates or ink as a covert authentication feature.

A device such as a seal or closure that demonstrates that a product or packaging has been (fraudulently) opened or otherwise accessed prior to its proper use.

A technique often used on card printers, especially for printing photographs of faces. Consists of a dye carried on a ribbon which sublimes above a specific temperature (ie. changes from solid to gas without passing through a liquid phase). The dye then diffuses into the upper layers of the substrate after which it re-solidifies upon cooling.

An ink that undergoes a reversible colour shift when heated and then cooled. The temperature change can be quite narrow so the viewer’s external body temperature, by applying, say, a thumb to the printed surface, is sufficient to trigger the transition.

A method of coating a very thin film of material – between a few nanometers to about 100 micrometres’ thickness – onto a substrate surface, or onto a previously deposited coating to form layers.

The superposition of two or more lightwaves, causing their mutual amplification or reduction depending on how the phases of these waves are related to each other.

The amount by which a measurement or calculation might change and still be acceptable.

The passing of light through an object (as opposed to light reflecting off or absorbed by an object). Watermarks in security paper are usually viewed in transmitted light by holding the paper up to the light source.

A person or legal entity providing and preserving digital certificates to create and validate electronic signatures and authenticate their signatories.The TSP has the responsibility to assure the integrity of electronic identification for signatories and services through strong mechanisms for authentication, electronic signatures and digital certificates.

A photochemical process in which high-intensity ultraviolet light is used to instantly cure or ‘dry’ inks, coatings or adhesives.

A first-level requirement of security paper, which needs to be made from virgin pulp without optical brighteners (ie. which is UV-dull). This is because optical brighteners mask or interfere with UV fluorescent security print and fibres.

Electromagnetic waves located beyond the blue end of the visible light spectrum, commonly defined within the wavelength range of 100nm-400nm. UV light is often used to analyse secure documents and banknotes, and security features such as paper brightness, fluorescent inks and fluorescent fibres. UV lamps used in shops and banks to verify banknotes operate at a wavelength of 365nm.

A material that absorbs energy at a longer wavelength outside the visible spectrum and emits in the visible spectrum. The materials that can achieve this effect are rare and therefore used for security marking.

A process for creating a layer of metal on a substrate. Involves heating the metal target material until it vapourises inside a vacuum chamber. This allows the metal vapour to condensate and form a thin layer over the top of the substrate. Vacuum deposition is a common method of producing security threads.

The use of digital print processes to apply personalised and serialised information, such as unique identifiers and barcodes, to products and documents.

Unlike raster images, a vector is not composed of separate dots (pixels). Vector graphics are composed of control points with curves in between them, defined by a mathematical formula. Vector graphics are often used for printing brochures etc., which do not require accurate transmission of all the shades of a particular colour and which can be described by curves. A great advantage of vector graphics is that the scaling of images does not affect their quality. One of the most popular vector graphics editors is Adobe Illustrator.

The process of verifying specific identity, document or product attributes, or determining the authenticity of credentials in order to give authorisation for a particular service.

A permission to enter the territory of a country. Can be in the form of a sticker with a multilevel security system, an insert, a stamp or a small sticker. A visa is placed on special pages of a travel document. There are machine-readable and non-machine-readable visas.

The reformation of cellulose to give a textile fibre that may carry security features and be embedded into security paper.

The fraudulent practice of making phone calls or leaving voice messages purporting to be from reputable companies in order to induce individuals to reveal personal information, such as bank details and credit card numbers.

A cryptographically signed data structure containing document features, encoded as a 2D barcode and printed on a document. The use of a VDS is recommended by ISO 22381:2018 as an open source, trusted entry point to allow all stakeholders to authenticate a unique identifier without having to go online, as well as access information on the security features used on a security document.

Wavelengths within the visible spectrum of 380nm-740nm.

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 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 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.