Glossary

A technique that projects tiny droplets of ink directly onto a substrate, which then penetrates the surface. As there is no printing plate, the technique is favoured for printing variable and personalised data.

A security printing process that is synonymous with banknote printing but also used on ID documents and some tax stamps. The area of the image to be printed is recessed into the surface of the printing plate via engraving or etching and the recessed areas filled with high-viscosity ink. The excess ink is wiped from the plates and heavy pressure is applied to transfer the ink to the paper. The resulting raised ink profile gives intaglio-printed documents their characteristic tactility.

The fundamental building block of all modern electronic devices. An integrated system of multiple miniaturised and interconnected components embedded into a thin substrate of semiconductor material (usually silicon crystal). Also known as a chip or microchip.

The result of the interaction between two superposing waves. Interference pigment flakes are used in colour-shifting inks, and interference foils with colour-shifting properties also exist.

A specialised agency of the United Nations responsible for establishing goals and objectives of traveller identification management.

An independent, non-governmental international organisation with a membership of 165 national standards bodies. Through its members, ISO brings together experts to share knowledge and develop voluntary, consensus-based, market-relevant international standards that support innovation and provide solutions to global challenges.

A network of physical objects that are embedded with sensors, software, and other technologies for the purpose of connecting and exchanging data with other devices and systems over the internet.

The ability of different information systems, devices and applications to access, exchange, integrate and cooperatively use data in a coordinated manner, within and across organisational, regional and national boundaries.

Name of the International Criminal Police Organisation, dating back to 1923. Its activity extends to all crimes of common law and especially those related to drug and gold trafficking, counterfeiting of money and capturing criminals harbouring in a foreign country. Police forces from most countries in the world take part in this organisation.

The ability of some materials to create rainbow effects when they reflect white light. Pearls, oil films on water and bubbles all show iridescence. The effect can be created with foils, ink, and laminates to create optically variable devices.

An ink containing (normally) tiny flakes of a shiny silicate mineral (mica) that interferes with incoming light to create a pearl effect on the finished document. Iridescent inks are sometimes used as low-grade security features. They are not the same as colour-shifting inks.

An ISO guidance standard for performance criteria for authentication solutions used to combat counterfeiting of material goods. This standard was revised under a new number: ISO 22383:2020.

An ISO compliance standard specifying requirements for a security printing management system for security printers. The certifying organisation behind 14298 is Intergraf.

An ISO standard for the specification and usage of visible digital seal (VDS) data format for authentication, verification and acquisition of data carried by a document or object.

An ISO guidance standard for the selection and performance evaluation of authentication solutions for material goods.

An ISO guidance standard for securing physical documents.

An ISO/IEC (International Electrotechnical Commission) standard specifying common rules for unique identification required to ensure full compatibility across different identities.

An ISO/IEC (International Electrotechnical Commission) standard specifying a method whereby data stored within a barcode or RFID tag are structured, encoded and digitally signed.

Atoms of the same element with the same number of protons (atomic number) but a different number of neutrons. 

A forensic marker technology that involves adding isotopic variants of one or more components of a formulation or packaging to allow the identification of genuine products.

The entity authorised to issue money of legal tender in a country. Generally, the expression is synonymous with a central bank or monetary authority. Also refers to government authorities issuing ID documents, tax stamps and other secure documents.

A system of encryption whereby a ‘key’ is required to decode a message. The key is usually a handheld device which renders meaningful that which was previously unintelligible. Public keys may be disseminated widely, whereas private keys are restricted to certain individuals, thereby limiting access to the encrypted information. See also Public key infrastructure.

An adjective whose roots in the Greek word ‘kinesis’ indicate motion. A holographic image which displays movement of form or colour is said to be kinetic. Often, such images are patterns rather than objects. The patterns can be made up of fine lines or graphic elements and appear to scintillate when moved.

A tamper-resistant feature employing a die-cutting process whereby adhesive-backed foils or papers are cut through, but the laminated backing paper is not.

An image which is applied on laminate coating to protect it against forgery. Screen printing and gravure printing are the most frequent printing methods used for laminate overprint.

The technique/process of manufacturing a material in multiple layers, using heat, pressure, welding or adhesives, so that the composite material achieves improved strength, stability, appearance or other properties. A laminate for ID documents is a mostly clear layer of plastic placed over the information on the ID data page to prevent tampering. The laminate will most often contain visual anticounterfeit features for further protection.

An acronym of ‘light amplification by stimulated emission of radiation’, a device that produces coherent light by stimulated emission of radiation.

Pictures and text are engraved in plastic laminates or cards by means of a laser. In the laser engraving process the data are written by blackening (carbonising) laser-sensitive foils. Using different photo-sensitive materials, colours can also be obtained.

Using energy delivered by a laser, holes of different shapes and sizes can be perforated into a substrate to produce serial numbers and other data, such as in an ID document.

An electrostatic digital printing process that produces text and graphics by repeatedly passing a laser beam back and forth over a negatively charged cylinder called a ‘drum’, which defines a differentially charged image. Laser colour digital copiers use this printing technique. It is a technique used in counterfeiting banknotes and other security documents.

An image formed by parallel straight relief strokes perpendicular to background strokes. The image is almost invisible in incidental white light at a right angle. It is visualised as an achromatic image in sliding white light at an acute angle of observation due to the shadow cast by the relief strokes. The background and image are applied by means of intaglio and have the same colour and stroke density.

A latent image formed by multicolour relief strokes. A latent multicolour image is slightly visible in white light. It is visualised as a chromatic image under oblique light. Every chromatic element of the image changes colour when rotating the document around the vertical axe without changing the angle of observation. Background strokes are applied by offset and relief lines by intaglio.

A latent image that has been fragmented and encoded according to a special algorithm. The image is visualised via a lenticular decoding device.

An array of lenses, designed so that when viewed from slightly different angles reveal different parts of an image. The most common example are the lenses used in lenticular printing to give an illusion of depth, or to make images that appear to change or move according to the viewing angle.

A multistep process consisting of creating a lenticular image from at least two existing images, and combining it with a lenticular lens. This process can be used to create various frames of animation (for a motion effect), offsetting the various layers at different increments (for a 3D effect), or simply to show a set of alternate images which may appear to transform into each other.

A relief printing process by which many copies are produced by repeated direct impression of an inked, raised surface against sheets or a continuous roll of paper. Letterpress printing remained the primary means of printing and distributing information until the 20th century, when offset printing was developed, which largely supplanted the role of letterpress in printing books and newspapers.

A commonly used means of grading security features created by the European Central Bank and adopted for use across the banknote industry. Level 1 refers to features that can be verified by the public, untrained examiners or specialist examiners with the naked eye. Level 2 refers to semicovert features that require some form of reading device or tool to be authenticated. They are typically deployed for use by retailers, cashiers and inspectors but are also detected by sensors in machines (the ECB defines Level 2a, 2b and 2c). Level 3 refers to covert features, generally rare chemicals or compounds that can only be identified by sensors in high speed processing machine verification used in cash centres. Level 4 authentication uses forensic examination to verify banknotes and is used solely by central banks/police.

Manipulating the width, length and height of line structures to create image and text effects. Using a higher resolution for the output results in effects not possible with commercially available software.

Chemicals that have properties between those of conventional liquids and solid crystals. Orientation of the crystal-like structure of the chemicals results in optically variable effects. Cholesteric liquid crystals have two refractive indices, a property known as birefringence (the ability to rotate the polarisation of incoming light and reflect circularly polarised light either clockwise or anticlockwise). Liquid crystal technology is used for security features that are validated with a polarisng filter.

A collective term for the effects of colour change or other visible characteristics under different sources of illumination.

An umbrella term for solving problems for which development of algorithms by human programmers would be cost-prohibitive, and instead the problems are solved by helping machines ‘discover’ their ‘own’ algorithms, without needing to be explicitly told what to do by any human-developed algorithms. While artificial intelligence encompasses the idea of a machine that can mimic human intelligence, machine learning does not. Machine learning aims to teach a machine how to perform a specific task and provide accurate results by identifying patterns.

A security feature requiring an instrument to verify its presence or data content.

Passports, visas and other travel documents that follow specifications set out in Document 9303 of the International Civil Aviation Organisation (ICAO) to facilitate automatic border management.

The MRZ in a machine-readable travel document contains personally identifiable information in the form of a sequence of alphanumeric characters and the symbol ‘<' spaced over two or three lines. The sequence of characters can be read by document readers to help automate inspection of travel documents.

The ability of a computer to see. The technology and methods used to provide imaging-based automatic inspection and analysis for such applications as automatic inspection, process control, and robot guidance, usually in industry.

An ink containing ferromagnetic components that have a specific reaction to the external magnetic field. Text or symbols applied by this ink can be identified by special magnetic sensors or visualised by magneto-optic converters. The ink can be applied on security threads and fibres,and used for printing images, serial numbers and barcodes.

Thin strip of magnetic material attached to a plastic card and encoded to record and store data.

An analytical technique to quantify known materials and identify unknown compounds within a sample and elucidate the structure and chemical properties of different molecules.

A 2D barcode (eg. datamatrix, QR code, dotcode), typically square-shaped, capable of representing more data per unit area than a linear barcode.

One million pixels. The term is used not only for the number of pixels in an image but also to express the number of image sensor elements of digital cameras or the number of display elements of digital displays.