Glossary

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 ‘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.

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.

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 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.

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 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 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.

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.

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

Skimming occurs when devices illegally installed on ATMs, point-of-sale terminals, or fuel pumps capture data or record cardholders’ PINs. Criminals use the data to create fake debit or credit cards and then steal from victims’ accounts.

Smart glasses integrate wireless networking and images into the frames and lenses of eyewear, just as with home computers and smartphones.

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.

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.

An impression, mark or relief formed on a paper substrate by means of pressure from a stamp.

The practice of representing information within another message or physical object so that its presence is not evident in human inspection. The advantage of steganography over cryptography alone is that the intended secret message does not attract attention to itself as an object of scrutiny

A type of hologram created from sequential images of a piece of movie footage. Each frame of the movie is converted into a vertical slit image and stacked against another slit image of the adjacent frame. The result is a hologram which, when the viewing angle changes from side to side, produces the same image motion as the movie footage, given that the frames are seen one after another.

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