Glossary

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 funds transfer system that allows the transfer of money or securities instantaneously. In most cases, RTGS is used for high-value interbank transactions that need to be cleared as soon as possible.

Refers to payment rails (platforms or networks via which payments are made) that are real-time, or at least very close – initiating, clearing, and settling in a matter of seconds.

A pack of 500 sheets of paper or other substrate.

A self-service ATM that checks deposited banknotes, sorts them and pays out fit notes to customers withdrawing banknotes.

A ‘step and repeat’ process whereby a single diffractive image is laid out in rows and columns in preparation for shim production. It can either be carried out mechanically or optically. In the mechanical process, the single image is made into a stamper which is impressed at predetermined intervals, into a plastic sheet. If done optically, the single image is exposed in a predetermined pattern onto a (glass) plate coated with a photoresist.

The recalibration of a country’s currency, typically due to hyperinflation and currency devaluation, whereby an old currency is exchanged for a new one at a fixed rate.

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.

A technique wherein a number of narrow ridges called reeds are carved or milled into the edges of coins. Reeding was originally undertaken as an anticounterfeiting measure to prevent gold and silver coins from being clipped. The technique is still used as an anticounterfeiting measure, and to help the visually impaired differentiate between coin denominations.

An unmodulated beam which, when directed at a photoresist forms a stationary interference pattern with the object beam. See also Object beam.

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

A hologram that is viewed by the reflection of white light. The diffractive planes within the depth of the recording material have a spacing which corresponds only to a single wavelength of light. This wavelength, usually green or yellow, is reflected back and reconstructs the image, the other colours being transmitted and absorbed by a black backing placed behind the hologram.

The bending of light as a beam passes from one medium (say air) to a different medium (say glass). For applications of refraction see High refractive index.

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 note printed with a special symbol before the serial number, or with a special serial number prefix, used to replace notes damaged during the manufacturing process.

The inverse indicator of the average life of a banknote: the higher the replenishment rate of the note, the lower its average life.

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.

Financial assets denominated in foreign currencies and held by central banks, which are primarily used to balance payments.

Occurs when a surface returns a large portion of directed light back to its source, from a much wider angle than a reflective surface. Retroreflective material is made using microlenses (microspheres).

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.

The back of the banknote or coin. Referred to as the ‘tails’ side in coin tossing.

A raised area of metal around the edge of a coin, intended to protect the rest of the coin from wear. Blanks are rimmed before they are struck as coins

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.

Also called returning exports, where products are manufactured and designated for export, then exported in order to avoid domestic taxes, and subsequently smuggled back into the original jurisdiction.

The informal name of the Bahamian CBDC.

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 to cover printed data with a opaque covering so it cannot be read until the final user removes the coating to read the data. Scratch-off ink is often used on lottery tickets to conceal winning numbers.

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.

The integration of physical and digital security features into a track and trace system to ensure that illicit traders are not able to, for instance, generate their own, functioning, unique identifying codes, nor copy existing codes, nor access confidential information contained in or linked to those codes. The difference between commercial parcel tracking systems and systems used for government-regulated products such as cigarettes, is one of security. Parcel tracking systems are at less risk of being manipulated by parties within the distribution chain than systems used to track cigarettes and other products exposed to illicit trade.

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.

Derived from the French expression seigneuriage, referring to the right of the lord (seigneur) to mint money. In the context of banknotes, seigniorage refers to the interest earned by the central bank when investing funds received via issuance of banknotes at face value, minus the cost of producing, distributing and replacing them.

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.

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.

The first step in mass hologram production is to create embossing plates called shims. A shim is made from a thin plate of metal, usually nickel, which is attached to the embossing cylinder. A ‘master’ or ‘mother’ shim is produced by an electro-deposition process whereby the plate with recombined images is immersed into a galvanic tank and metallic nickel is caused to accumulate on its surface. The mother shim is then usually used to prepare ‘daughter’ shims for the mechanical embossing process.

At some point in the hologram replication process, one or more metal shims need to be mounted around the circumference of the embossing cylinder. The point at which the shims join often produces a visible line in the resulting embossed film. This line is most problematic where the finished result is intended to be a continuous pattern. Those skilled in the art have developed procedures which successfully minimise or even eliminate such optical discontinuities in the final product.

A papermaking machine which forms a thicker carrier sheet, on top of which is placed a second ‘laminated’ sheet. Wide security threads – either embedded or ‘windowed’ – can be incorporated between the sheets with little or no reduction in paper strength.

A subset of the infrared band in the electromagnetic spectrum, covering wavelengths from 1.4-3 microns. Unlike midwave infrared (MWIR) and longwave infrared (LWIR) light, which is emitted from the object itself, SWIR is similar to visible light in that photons are reflected or absorbed by an object, providing the strong contrast needed for high resolution imaging.

An inspection process that examines the visible and machine-read properties of newly printed banknotes before being issued. The process is used to reclaim good notes from defective sheets that, despite being fit for circulation, would otherwise be destroyed.

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