Glossary

A coloured or reflective disc containing a security feature and embedded in paper during manufacture.

Plasma is superheated matter – so hot that the electrons are ripped away from the atoms, forming an ionised gas. It comprises over 99% of the visible universe. In the night sky, plasma glows in the form of stars. That branch of lightning that cracks the sky is plasma. So is the sun… and so are neon signs on city streets. Plasma is often called ‘the fourth state of matter’, along with solids, liquids and gas. Just as a liquid will boil, changing into a gas when energy is added, heating a gas will form a plasma – a soup of positively charged particles (ions) and negatively charged particles (electrons).

In physics, a plasmon is a quantum of plasma oscillation. Just as light consists of photons, the plasma oscillation consists of plasmons. The plasmon can be considered as a quasiparticle since it arises from the quantisation of plasma oscillations,

The generation, detection, and manipulation of coherent electron oscillations (known as surface plasmon polaritons), as they travel together with an electromagnetic wave along the interface between a metal (eg. silver, gold) and a dielectric material (eg. glass, air) at the nanometric scale. Inspired by photonics, plasmonics follows the trend of miniaturising optical devices, and can be applied as a security feature. The plasmons can be controlled through careful modelling and application of, among other things, the dielectric and metal layer thickness in a ‘sandwich’ structure. When the sandwich structure is applied as a device to a security document, it allows light that falls on the surface of the device to be controlled in terms of its wavelength (allowing control over the colour) and amplitude (giving rise to the intensity, or brightness of the colour generated).

The alignment of the electric and magnetic fields in a particular orientation in a lightwave. If all the waves in a beam of light move up and down or from side to side together, the beam is said to be plane-polarised. Some materials have the ability to filter out all lightwaves except those in a particular direction. Other materials are said to be optically active if they are able to change the angle of a plane-polarised beam of light. Liquid crystals often have this property and this enables them to be detected.

An optical device which transforms unpolarised light into polarised light. It is used to examine light reflected from ink or thin-film coating. It blocks light rays of a specific polarisation direction while letting light rays of other polarisation directions pass.

An increasingly popular thermoplastic polymer used as the substrate of choice for ID cards and the data pages of passports, due to its durability, high dimensional stability and transparency. It also lends itself to laser engraving and ablation for additional security features.

A thermoplastic polymer resin of the polyester family, used to make the most common container in the soft drink market today: the plastic bottle. Also used as the base material for most surface-applied holograms and security threads.

A substance or material consisting of very large molecules, or macromolecules, composed of many repeating subunits. Plastic and polyester are all polymers. Polymer banknotes were first introduced in Australia and are widely used around the world.

A laboratory technique for rapidly producing (amplifying) millions to billions of copies of a specific segment of DNA, which can then be studied in greater detail.

A thermoplastic polymer used as a substrate in many documents. However, polycarbonate is often preferred as a substrate for security printing and documents requiring high durability.

A stacked linear barcode format used in a variety of applications such as transport, identification cards, and inventory management. The ‘417’ signifies that each pattern in the code consists of 4 bars and spaces in a pattern that is 17 units (modules) long.

Preparatory work required on original materials, such as films, files and plates to carry out the printing of a banknote or other security document.

A label construction made up of three layers: a face material, a pressure-sensitive adhesive, and a backing sheet coated with a release agent. Pressure-sensitive labels only need the pressure of a hand to be applied to an item.

In colour printing, print registration is the layering of printed patterns to form a multicolour image. Registration error refers to position misalignment in overlapped patterns, resulting in printed colours in the wrong areas, overprint or white space.

A plant for producing banknotes and other security documents. Printworks can be either state or central bank-owned or run by commercial companies.

The overprinting of two or more coloured inks to create a blended colour affect that is difficult to match on copiers. Prismatic colour blending is visually similar to split fountain printing, but differences become apparent when the images are magnified.

A set of policies, processes, server platforms, software, and workstations used for administering public key certificates and public-private key pairs, including the ability to issue, maintain, and revoke certificates.

A cooperative arrangement between two or more public (ie. government) and private sector entities.

A multilingual site with information on authentic identity and travel documents in the EU. Document descriptions include technical descriptions of some of the most important security features on the document. Document experts in all EU member states as well as Iceland, Norway and Switzerland provide and select the information to be released to the general public via PRADO.

A fibrous material produced by mechanically or chemically reducing plants to their component parts from which pulp, paper and paperboard sheets are formed after proper slushing treatment.

A computer that uses specialised technology – including computer hardware and algorithms that take advantage of quantum mechanics – to solve complex problems that classical computers can’t solve, or can’t solve quickly enough.

Semiconductor particles a few nanometres in size with optical and electronic properties that differ from larger particles due to quantum mechanics. Quantum dots may be ‘tuned’ to provide specific visual effects.

A fundamental theory in physics that describes the behaviour of nature at and below the scale of atoms. It is the foundation of all quantum physics.

The basic unit of information used to encode data in quantum computing. Can be best understood as the quantum equivalent of the traditional bit used by classical computers to encode information in binary.

A type of 2D matrix barcode which stores information as a series of pixels in a square-shaped grid. Typically, smartphones are used to scan QR codes, displaying an image of the code and converting it to, say, a standard URL for a website. QR codes can store up to 4,296 alphanumeric or 7,089 numeric characters and are clearly distinguished from datamatrix barcodes by large squares placed at three corners of the code, which are used for alignment. Compared to standard UPC barcodes, QR codes offer faster reading of the optical image and greater data storage capacity in applications such as product tracking and item identification.

An act of cybersecurity fraud using QR codes to redirect victims to malicious websites or prompt them to download harmful content. The goal of this fraud is to steal sensitive information, such as passwords, financial data, or personally identifiable information, and use that information for other purposes, such as identity theft, financial fraud, or ransomware.

A wireless, non contact technology that uses radio waves to transfer data and passively identify a tagged object. RFID systems are usually comprised of an RFID reader, microchip tags, and antennas. The reader gives off radio waves and gets signals back from the tag, while the tag uses radio waves to communicate its identity and other information. The tags are now so small that they can be neatly implanted into paper. They can typically be detected at distances ranging from a few millimetres to several metres. RFID is used in various commercial and industrial applications, including tracking items along a supply chain.

A form of offset security printing involving the split duct process, which results in a gradual change of two specific colours.

A non-destructive analytical technique used to identify and study the molecular composition and structure of materials. It works by detecting molecular vibrations, which provide unique spectral fingerprints for different substances. Named after Indian physicist C V Raman, who discovered the Raman Effect, this technique is widely used in chemistry, materials science, biology, and other fields for analysing a wide range of substances.

A 2D picture represented as a rectangular grid of pixels.

The task of converting a vector graphic image into a raster image (ie. a series of pixels, dots or lines which recreate the vector image). The higher the resolution, the greater the number of pixels per unit area. Raster images are used for ensuring a smooth transition of colours and shades, with the most common use being for processing photos. The most popular raster graphics editor is Photoshop.

A pack of 500 sheets of paper or other substrate.

A system representing the colours used on a digital display screen. Red, green and blue can be combined in various proportions to obtain any colour in the visible spectrum.

The bouncing of light off an object (as opposed to light that transmits through or is absorbed by an object).

The darkest black that can be made from the four CMYK ink colours, consisting of 100% cyan, 100% magenta, 100% yellow, and 100% black.

An entity that relies upon the credentials and authentication mechanisms provided by an ID system, typically to process a transaction or grant access to information or a system.

A common business process for collecting written information about the capabilities of various suppliers. Normally, an RFI follows a format that can be used for comparative purposes. An RFI is primarily used to gather information to help make a decision on what steps to take next. RFIs are therefore seldom the final stage of procurement and are instead often used in combination with a request for proposal (RFP) and request for quotation (RFQ).

A document that solicits a proposal from suppliers, often as part of a bidding process, by an agency interested in procuring a commodity or service. An RFP is used when a general need or problem must be solved, and potential sellers are proposing solutions and how much they will cost. Companies evaluating an RFP must consider not only the cost but the effectiveness of the solution.

A document that solicits quotations from suppliers often as part of a bidding process, by an agency interested in procuring a commodity or service. An RFQ is used when a quote is needed for a specific need and solution.

A security film laminated to the surface of documents such as driving licences and ID cards. Can carry primary images viewable under both ordinary diffuse lighting and retroreflective viewing conditions, as well as retro-images that can only be seen under retroreflective conditions, eg. with a flashlight or specialised retroviewer.

A printing press where the images to be printed are curved around a cylinder. There are three main types of rotary press: offset (including web offset), rotogravure, and flexography.

The schablon (stencil) multiple colouring process is used in intaglio printing to enable more than one colour to be printed simultaneously and accurately with one printing plate. The individual colours are applied via individual stencils that match the elements or parts of the required final design. The inks may overlap to a small extent and in the final printed image a slight colour transition can therefore be seen.

A process that uses a fine mesh with an impermeable coating, selected areas of which have been removed to allow ink to pass through. Screen printing produces a thick ink layer ideal for printing optical effect security features.

Inclusions added to security paper during manufacture comprising randomly distributed short thin fibres with specific optical or spectroscopic properties.The fibres can be made of silk, plastic or metal, and may be visible, invisible, multicoloured or fluorescent under UV light.

Paper typically manufactured from wood pulp or cotton containing security features such as watermarks and security fibres.

Polyester threads that are either fully or partially embedded down the length of paper during the paperforming process. Fully embedded threads – typically less than 1.8mm wide – can only be viewed when the document is held up to the light. Partially embedded threads appear intermittently on one side of the paper. Their size is typically up to 4mm wide and they act as carriers for a range of overt security features.

A security feature that, when held up to the light, combines elements of the front and back of a banknote or secure document into a specific image.

A semiconducting material has an electrical conductivity value falling between that of a conductor, such as metal, and an insulator, such as glass. Semiconductive inks can be used to create printed antennae.

A security feature requiring simple, sometimes commercially available tools to view it, such as ultraviolet (UV) lights, polarising filters, magnifiers and lenses. The examiner needs to know where the features are and how to examine them and they are not normally made known to the general public.