Glossary of Tax Stamps

Activation – A stage in the use of a tax stamp, when applicable taxes become due. Also refers to a unique identifier used for track and trace, which is activated at the point where it is applied to an item and scanned, and then linked with that item in a central database.

Adhesive – Also referred to as glue. The material that sticks a label/tax stamp onto a container.

Adulteration – The tampering of a product to extend its use by dilution or deliberate addition of a harmful substance that renders the product dangerous or less effective.

Aggregation – Allows the identification of individual items within an outer package to be recorded and associated with a unique identifier applied to that package. The identifier can then be used to record the movement of the outer package (together with the movement of its contents) through the distribution chain. In the case of cigarettes, this parent-child relationship can record the hierarchy between packs and cartons, cartons and master cases, and master cases and pallets.

Algorithm – A mathematical procedure or formula for solving a recurrent problem, based on conducting a sequence of specified actions. For example, an encryption algorithm transforms data according to specified actions to protect that data.

Alphanumeric – A character set that contains letters and numbers.

Analogue – Using a wristwatch as an example, an analogue watch uses the movement of hands over a dial to represent passing time. It’s not the same thing as time itself, but an analogy of time. Same thing with a ruler – that little strip of wood is a representation of your finger: another analogy.

Anti-copy feature – A security feature that does not accurately reproduce when copied using a mechanical or digital device.

Anti-Stokes feature – Sometimes referred to as up-conversion, whereby infrared radiation is used to create an emission within the visible spectrum.

Anti-tampering feature – A feature such as a secure closure specifically used to resist the opening of a container or identify that a container has been opened.

Assay – A procedure that identifies the presence and amount of a substance (such as a marker or taggant) in a particular composition.

Asymmetric Cryptography – A process that uses a pair of related keys – one public and one private – to encrypt and decrypt a message and protect it from unauthorised use.

Authentication – The process of determining that an item is genuine.

Banderol(e) (tax) – A band or tape used as a closure to seal or provide tamper resistance. A banderol(e) is another name for a tax stamp, usually referring to the long stamp placed over the neck of alcohol bottles.

Barcode – A method of representing data in a visual, machine-readable form.

Barcode – matrix – A two-dimensional barcode (eg. datamatrix, QR Code, dotcode), typically square-shaped, capable of representing more data per unit area than a linear barcode.

Barcode –linear – A series of vertical printed black bars of controlled thickness and separation representing variable data information in a linear, one-dimensional format (eg. UPC, EAN).

Bi-fluorescence – A component in a mixture (such as ink) that provides two distinctive emission spectra when excited by two different wavelengths.

Biaxially orientated polypropylene (BOPP) – A variant of polypropylene, a thermoplastic polymer that forms an ideal printing surface for labels.

Biometrics (document) – See Fingerprinting.

Blockchain – A timestamped series of immutable records of data that are managed by a cluster of computers as a distributed ledger that is not owned by any single entity. The blocks of data are secured and bound to each other using cryptographic principles.

Build-operate-transfer (BOT) – A project delivery method where a private entity receives a concession from the public sector to finance, design, construct, own, and operate a facility stated in the concession contract. This enables the project proponent to recover its investment, operating and maintenance expenses in the project. BOT is usually used in public–private partnerships.

Carton – A packaging unit of tobacco products. One carton usually contains 10 packs (or 200 individual cigarettes).

Cellulose – A polysaccharide comprising long unbranched chains of linked glucose units. For example, paper and starch.

Check digit – Also known as a checksum character, it is the last digit of a barcode number used to verify that the information on the barcode has been entered correctly. A barcode decoder calculates the checksum by performing a series of mathematical operations on the digits that precede the check digit, and comparing the result of the calculation to the value of the check digit.

Classic hologram – A classic hologram is usually made using a 3D object, often a model. A laser beam is split in two and part is diverted onto the object, reflected off it then allowed to combine (or interfere) with the other part of the beam known as the reference beam. The classic hologram is a recording of the interference pattern between the object and reference beams. A well-known example of a classic hologram is the dove used by Visa on their credit cards.

CMYK colours – See Four-colour printing.

Coating (substrate) – Typically an integral layer of material added to alter, enhance or protect the properties of the underlying base substrate.

Code – A system of words, letters, figures, or symbols used to represent certain information.

Cold foiling – A foil application process that does not require heat.

Colour-shift – An ink or optically variable device that exhibits a different colour at different viewing angles.

Competent authority – A government agency designated to implement a system, such as a tax stamp and track and trace solution.

Counterfeit – To simulate, reproduce or copy an item without authorisation.

Covert security feature – Also known as Level 3 security, covert (or hidden) features require a detector or instrument in their detection, which are usually only available to enforcement authorities. The general public and supply chain operators generally do not know about these features.

Cryptography – A method of protecting information and communications through the use of codes.

Dandy roll – See Fourdrinier.

Data carrier – This usually refers to a barcode (usually 2D) that represents track and trace data in a machine-readable format.

Data repository – A database used to store track and trace and other data.

Datamatrix code – A two-dimensional code consisting of black and white cells or dots arranged in either a square or rectangular pattern, also known as a matrix. The information to be encoded can be text or numeric data. Usual data size is from a few bytes up to 1556 bytes.

Decal – An image or print that can be moved from one surface onto another, usually with the aid of heat or water.

Decitex – A measure of textile thickness.

Decoding – The translation of a code into a format that is more generally understood.

Decryption – The process of converting encrypted data back into its original form, often with the use of a covert key or password.

Demetallisation – A two-stage process in which metal, usually aluminium, is deposited onto a hologram or DOVID (see below) and then selectively removed. The removal is achieved by either first printing a protective resin onto the metallic layer then dissolving away the unprotected metal, or ablating the metal with a laser beam.

Die-cutting – The general process of using a die (a specialised tool to cut or shape material) to shear webs of low-strength materials, such as fibre, foil, paper, plastics, pressure-sensitive labels and sheet metal.

Diffraction – The bending of light around an object or the spreading of light as it passes through an aperture.

Diffraction grating – An optical component with a periodic structure that splits and diffracts light into several beams travelling in different directions.

Diffractive Optically Variable Image Device (DOVID) – Also known as a DOVID. The collective term for images that display complex visual effects that change according to the viewing angle, based on the phenomenon of diffraction. These effects are varied and are typically three-dimensional (exhibiting depth as well as width and height), kinetic, multi-channel (in which one image, or part of an image, changes into another) or animated (images with these effects are known as stereograms).

Digital – The storage, transmission, manipulation and reproduction of data, images, sounds, etc., by a process that uses groups of electronic bits represented as 1 or 0.

Digital printing – Any printing technology capable of producing printed materials directly from a computer file. Digital printing does not require an intermediary medium such as film, nor an intermediary machine such as a plate-maker. Non-impact printing such as laser, inkjet and dye sublimation all fall into this category.

Digital tax stamp – Commonly refers to a tax stamp which carries a digitally generated and printed unique identifier.

Direct marking – A method of applying codes or information directly onto the product, without the use of a tax stamp or other label.

Distributed ledger – A series of replicated, shared, and interconnected digital data spread across multiple sites, countries, or institutions, with no central hub. Generally associated with blockchain systems.

Diversion – The unauthorised transfer of goods from one jurisdiction to another to bypass taxation or regulatory requirements.

DNA taggant – Organic molecular particles based on DNA (deoxyribonucleic acid) carbon compounds, either naturally occurring or synthetic.

Dots per inch (DPI) – Used to measure the resolution of an image both on screen and in print. DPI measures how many dots fit into a linear inch, therefore the higher the DPI, the more detail can be shown in an image.

E-pedigree – An electronic statement of a product’s history and passage through the supply chain, with each movement and transaction recorded so that, at any point in the chain and at its end, the lineage of the product can be obtained.

Economic operator – Under the EU Tobacco Products Directive this means any natural or legal person who is involved in the trade of tobacco products, including for export, from the manufacturer to the last economic operator before the first retail outlet.

Electromagnetic spectrum – The complete range of light that exists, from radio waves to gamma rays.

Electron beam lithography (e-beam) – Electron-beam lithography (or e-beam lithography, EBL) is the technique of scanning a focused beam of electrons to draw custom shapes on a surface covered with an electron-sensitive film called a resist. The whole origination process is undertaken in a vacuum chamber where the e-beam writes onto the resist plate. This is sometimes referred to as a direct write process.

Electronic Product Code Information Service (EPCIS) – A global GS1 product code standard for creating and sharing visibility event data, both within and across enterprises, to enable users to gain a shared view of physical or digital objects within a relevant business context.

Embossing – The transfer of a raised pattern from a hard plate to a softer material. This mechanical transfer is usually facilitated by means of heat and always with pressure.

Encoding – The conversion of information or data into a code.

Encryption – The conversion of data or information into a format that requires a key or password to access the data.

EU Tobacco Products Directive (TPD) – The Tobacco Products Directive (2014/40/EU) is a directive of the European Union which places limits on the sale and merchandising of tobacco and tobacco related products in the EU. The TPD aims to improve the functioning of the internal market for tobacco and related products, while ensuring a high level of health protection for European citizens. Under the TPD, all member states were required to implement unit-level track and trace and security features by May 2019.

Excise tax – Taxation imposed by countries as a levy for specific items such as tobacco or alcohol. Also call sin tax due to its association with so-called ‘sinful’ products.

Expression of Interest (EOI) – Part of the qualification process to receive a tender document. The buyer (ie. a government organisation) is requesting a provider to express an interest in providing goods and services for a project.

FCTC Protocol – World Health Organisation Framework Convention on Tobacco Control (WHO FCTC) global treaty, and its Protocol to Eliminate Illicit Trade in Tobacco Products. The Protocol requires all parties to implement secure track and trace systems by 2023.

Fingerprinting – Also called document biometrics, this refers to the combination of scanning and software programmes with unique physical characteristics intrinsic to a product or tax stamp. Fingerprinting is based on the fundamental premise that at the microscopic or molecular level the characteristics of every printed document or package are unique to that item.

Fiscus – State treasury.

Flexography (flexo) printing – A method of printing whereby a mirrored 3D relief of the required image is made in a rubber or polymer material. A measured amount of ink is deposited upon the surface of the printing plate, after which the print surface rotates, making contact with the print material (substrate) and transferring the ink.

Fluorescence – A type of luminescence, describing the ability of some molecules or materials to absorb ultraviolet energy and immediately re-emit this energy within the visible spectrum, as a glowing light. The emitted light disappears as soon as the excitation light is extinguished. There is no persistence of emitted light as in the case of phosphorescence.

Foil – A material comprising a polyester carrier with one or more coatings, a release layer and an adhesive layer. The foil is transferred – generally by heat – onto paper and label stock, and the carrier is stripped away, leaving the coating which is bonded to the substrate by the adhesive. This coating can be colour-shifting, iridescent, metallised, holographic etc. Also known as hot stamping or transfer foil.

Forensic security feature – Also referred to as Level 4 security, forensic features are reserved for special departments or officials. Special tools or laboratories are required to reveal their presence and characteristics. The presence and nature of these features are generally kept a closely guarded secret and they are typically used after a raid to provide definitive proof of the authenticity of a product or document. Such data can be used, if necessary, as evidence in a court of law.

Four-colour printing – Also known as process colour printing – a conventional printing method based on four colours: the so-called CMYK colours of cyan, magenta, yellow and black. Together, these colours can reproduce on paper almost 70% of the colours visible to the human eye.

Fourdrinier – The most common method of producing watermarks in tax stamps. Fourdrinier (or dandy roll) is a paper-making process which presses a raised pattern into the newly formed wet surface of paper.

Frangibility – Capable of being broken. Refers to security labels which break up when removed or tampered with.

Fugitive ink – Solvent- or water-based inks that are printed onto a security document. When solvents or ink eradicators are applied to the document the fugitive ink spreads out creating a smudge, which denotes the attempt to tamper with the print.

Gas chromatography – An analytical technique to separate the chemical components of a sample mixture and then detect those components to determine their presence or absence and how much is present. The components are usually organic molecules or gases.

Gas chromatography-mass spectrometry – An analytical method combining gas-chromatography and mass spectrometry to identify different substances within a test sample. Used in fuel integrity programmes.

Geo-location – The identification of the geographic location of an object.

Gravure (rotogravure) printing – A type of intaglio printing process, which involves engraving an image onto a cylinder. Like offset printing and flexography, gravure uses a rotary printing press.

GS1 – GS1 is a not-for-profit organisation that develops and maintains global standards for business communication. The best known of these standards is the barcode, a symbol printed on products that can be scanned electronically. 

Guilloche pattern – A printed security feature composed of geometric, complex patterns of interlaced or interwoven curved fine lines that are difficult to reproduce using digital print or photocopiers.

Heat transfer printing – A method of lamination whereby heat is used to transfer print from one substrate to another. Most of the US tax stamps are applied by this method.

Hologram – The term ‘hologram’ is derived from two Greek words: ‘holos’ meaning whole or complete and ‘graphos’ meaning an image. The term therefore describes a recorded image which is complete, in that it shows the whole volumetric space of the object or image, as opposed to a conventional picture, painting or photograph which displays an object from a single viewpoint.

Hot foiling (stamping) – A method of transferring a foil from one substrate to another by the application of heat and pressure.

Hot-melt adhesive – An adhesive that is solid at room temperature and becomes liquid when heated. Used to bond two surfaces when cool.

Hydrogen bonding – A chemical bond in which a hydrogen atom of one molecule is attracted to an electronegative atom (usually nitrogen or oxygen) in the same or a different molecule. Typically, the properties of water are an example of hydrogen bonding.

Illicit (cheap) whites – Cigarettes which are legally produced under unique brand names – or no brand name at all – and destined primarily or exclusively for illicit distribution, outside the jurisdiction where they are produced.

Illicit trade – The production, distribution or sale of counterfeit, adulterated or diverted goods via illegal and unregulated channels. Also includes the evasion of taxes on legally produced goods.

Immunoassay column recognition marker – A biochemical test measuring the presence or concentration of a molecule in an extracted substrate using an antibody or antigen.

Infrared (IR) light – The part of the electromagnetic spectrum between 700nm and 1.0mm wavelength. IR light lies immediately beyond red light and is therefore invisible to the naked eye.

Inkjet printing – A type of digital printing that can process variable data using droplets of ink sprayed onto a substrate.

Intaglio printing – 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.

Interference (light) – The result of the interaction of two intercepting light waves. Interference pigment flakes are used in colour-shifting inks and interference foils with colour-shifting properties also exist.

International Standards Organisation (ISO) – 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.

Interoperability – 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.

Iridescence – 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 and inks to create optically variable devices.

ISO 12931:2012 – An ISO guidance standard for performance criteria for authentication solutions used to combat counterfeiting of material goods.

ISO 22381:2018 – An ISO guidance standard for establishing interoperability among object identification systems to deter counterfeiting and illicit trade.

ISO 22382:2018 – An ISO guidance standard for the content, security, issuance and examination of excise tax stamps.

ISO 22383:2020 – An ISO guidance standard for the selection and performance evaluation of authentication solutions for material goods”

Isotope – One or more atoms with the same number of protons (atomic number) but a different number of neutrons. 

Keys (private and public) – See Lock and key

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

Laser printing – 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.

Latent image – A semi-hidden printed image that can only be seen at a certain viewing angle.

Letterpress printing – 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 its role in printing books and newspapers.

Level 1 security – See Overt security feature

Level 2 security – See Semi-covert security feature

Level 3 security – See Covert security feature

Level 4 security – See Forensic security feature

Line-width modulation – 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.

Liquid crystal – A state of matter with properties between those of conventional liquids and solid crystals. Orientation of the crystal-like structures is possible resulting in optically variable effects. Liquid crystal technology is used for security features based on polarisation effects.

Lithography – See Offset printing

Lock and key – A system of encryption whereby something (the ‘key’) is required to decode the 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.

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

Machine-readable – A security feature requiring an instrument to verify its presence or data content.

Marker (forensic) – See Taggant

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

Master case – A shipping unit of tobacco products – usually comprising 25 or 50 cartons.

Metallic ink – Printing inks that contain metallic components that provide a metallic finish to the applied substrate.

Metallisation – The coating of films or surfaces with a very thin layer of metal using a metal deposition technique. Metallisation is what gives holograms their silver or similar metallic appearance.

Metamerism – The effect generated when using a pair of similarly shaded inks, the colour and contrast of which appear virtually identical in normal light, but which have different spectral responses so that, when viewed with a filter or under special illumination, one ink displays different effects or colours to the other.

Metasurface (electromagnetic) – Thin two-dimensional metamaterial layers that allow or inhibit the propagation of electromagnetic waves in desired directions.

Micron – A unit of measurement commonly used in authentication when referring to the thickness or gauge of physical substrates and features. One micron is equal to one millionth (10-6) of a metre.

Microprint/microtext – This is print that is so small that it cannot be reproduced by photocopying or scanning, and can only be read under magnification.

Moiré pattern – Images formed by the superimposition of two patterns with different periodicities, so that they display different visual effects according to the viewing angle.

Mould-made paper – A method of paper manufacture that drains stock through a mesh cylinder. This is not customarily used for documents like tax stamps due to the weight of the paper and is rather used for banknote paper production.

Nanotechnology – The science and technology of precisely manipulating the structure of matter at the atomic and molecular level (one nanometre is one billionth of a metre). In the authentication arena, nanotechnology is being used to explore and develop unique optical phenomena for use in new material and security features.

Near-field communication (NFC) – A method of wireless data transfer between two electronic devices over a distance of 4cm or less.

Near-infrared – The part of the electromagnetic spectrum between 780nm and 2500nm, near-infrared is the region closest in wavelength to the red light detectable by the human eye.

Offset printing – The technique whereby ink is spread on a metal plate with etched images, then transferred to an intermediary surface such as a rubber blanket, and finally applied to paper by pressing the paper against the intermediary surface. Also known as lithography. Offset is the most common printing method for tax stamps.

Optically variable device (OVD) – Overt, Level 1, security features with dynamic characteristics that change according to the viewing angle – for example from one colour to another, or from one image to another.

Other tobacco products (OTP) – Tobacco products other than cigarettes, such as cigars and pipe tobacco.

Overt security feature – Also referred to as Level 1 security features, these are features that are apparent to the human senses – especially the senses of sight and touch – without the need for additional readers and instruments. Such features are designed to enable all stakeholders, including consumers to identify if a product is genuine or not.

Pearlescence – Visibly similar to iridescence but with s slightly ‘milky’ appearance at certain viewing angles.

Phosphorescence – A fluorescence that continues for a period after the stimulus that produced the emission has stopped.

Photochromism – The phenomenon whereby a material changes colour or transparency in response to a light.

Pixel – The smallest resolvable area of an image.

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

Polarisation – The orientation of light waves into a predominating angle. 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 light waves 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.

Polyethylene terephthalate (PET) – A thermoplastic polymer resin of the polyester family, used to make the most common container in the soft drink market today: the plastic bottle.

Polymer – A substance or material consisting of very large molecules, or macromolecules, composed of many repeating subunits. Plastic and polyester are all polymers.

Pressure-sensitive application – 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.

Process colour printing – See Four-colour printing.

Production monitoring systems (automated) – Systems installed on domestic product manufacturing lines, using sensors and scanners to provide tax and other government authorities with full visibility on what is being produced and ensure that every production unit has been affixed with a valid tax stamp/secure label.

Public-private partnership (PPP) – A cooperative arrangement between two or more public (ie. government) and private sectors.

QR (Quick Response) code – Two-dimensional matrix barcodes that can be used to identify URLs, so that smartphone users can photograph the code and retrieve information about its originator’s company or product. QR codes can store up to 4,296 alphanumeric or 7,089 numeric characters and are clearly distinguished from datamatrix barcodes by the four squares at each corner that are used for alignment.

Quantum dot – Tiny semi-conductor particles measuring a few nanometres in size. Quantum dots have optical and electronic properties that differ from larger particles due to quantum mechanics. They may be ‘tuned’ to provide specific visual effects.

Radio frequency identification (RFID) device – Small microchips containing unique and individual information related to the item on which the chip is attached. The chip, and therefore the information, is addressed by means of radio waves conveyed to the chip by an attached antenna. These devices 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.

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

Rasterisation – 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.

Reflected light – The bouncing of light off an object (as opposed to light that transmits through an object).

Request for Information (RFI) – A common business process for collecting written information about the capabilities of various suppliers. Normally it 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 and are instead often used in combination with a request for proposal (RFP) and request for quotation (RFQ).

Request for Proposal (RFP) – 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.

Request for Quotation (RFQ) – 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.

Rotary printing press – A printing press in which the images to be printed are curved around a cylinder. Today, there are three main types of rotary press: offset (including web offset), rotogravure, and flexography.

Rotogravure – See Gravure printing

Roundtripping – 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.

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

Secure track and trace – 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 – as well as other products exposed to illicit trade.

Security fibre – Inclusions added to security paper during manufacture comprising randomly distributed short thin fibres with specific optical or spectroscopic properties.

Security paper – Paper typically manufactured from wood pulp or cotton containing security features such as watermarks and security fibres that are difficult to reproduce.

Security thread – Polyester threads that are either fully or partially embedded down the length of paper during the paper-forming 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. They are typically up to 4mm wide and act as carriers for a range of overt, or visible, security features.

Semi-conductor – A semi-conducting material has an electrical conductivity value falling between that of a conductor, such as metal, and an insulator, such as glass. Semi-conductive inks can be used to create printed antennae.

Semi-covert security feature – Also known as Level 2 security features, semi-covert features require simple, sometimes commercially available tools to view them, 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. They are typically designed for retailers, manufacturers and other members of the supply chain, as well as for officials during routine inspections.

Serialisation – 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.

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

Sin tax – See Excise tax.

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

Smuggling – 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.

Speckle pattern – Produced by the mutual interference of a set of coherent wave fronts. 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.

Spectroscopy – The analysis of the wavelength and intensity of a specific area of the electromagnetic spectrum in order to undertake a qualitative or quantitative analysis.

Split duct process – Also known as rainbow printing. This is employed in offset printing where colours are intentionally allowed to overlap on the transfer cylinder producing a gradated effect.

Spot colour – Also known as a solid colour, this is 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.

Structured Query Language (SQL) – The standard language used to communicate with relational database management systems (ie. systems which store and provide access to data points that relate to one another). SQL statements are used to perform tasks such as updating and retrieving data.

Substrate – The material or base – eg. paper or film – to which a feature is applied, or in which it is incorporated.

Supply chain – Individuals or organisations involved in getting product from manufacturer to consumer.

Surface relief hologram – The most ubiquitous and popular type of hologram, mainly exhibiting a characteristic rainbow-coloured pattern. Surface relief holograms are mass-produced mechanically by embossing or casting a relief pattern or image into a thermoplastic film or a viscous coating on a film or paper.

Symbology – A protocol for arranging the bars and spaces of barcodes for the encoding of numbers, letters and binary numbers.

Taggant – Molecular or microscopic particles 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. Also known as forensic markers.

Tamper evidence – Devices such as seals and closures that demonstrate that the product or packaging has been opened or otherwise accessed.

Tax stamp – A label or tag applied to an item that denotes that tax or excise duty has been paid on the item.

Thermal transfer printing – See Heat transfer printing

Thermochromic – A phenomenon whereby materials change colour when their temperature changes, such as when the material is rubbed by a finger to generate heat.

Tracing – The process of identifying the origin of an item or where it has been.

Track and trace (traceability) – The process of monitoring and recording the past and present whereabouts of a shipment, as it passes through different operators on its way to its destination, through a distribution network.

Tracking – The process of following an item through the supply chain so its whereabouts are known at all times.

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

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

Ultraviolet (UV) dull substrate – A first-level requirement of security paper, which needs to be made from virgin pulp which is free of optical brighteners (ie. which is UV-dull). This is because optical brighteners mask or interfere with UV fluorescent security print and fibres.

Ultraviolet (UV) light – The part of the electromagnetic spectrum between 100nm and 400nm, or between visible light and X-rays.

Unique identifier (UID or UI) – Also referred to as a unique identification marking (UIM) in the WHO FCTC Protocol to Eliminate Illicit Trade in Tobacco Products. A unique identifier, in the context of excise goods traceability, is a serial number, assigned by a central authority for application to unit packages of excise products for the purpose of track and trace. No two serial numbers are the same, thereby allowing for the identification of individual retail-saleable items throughout the supply chain.

Unit packet – The smallest individual packaging of a tobacco product (one pack of cigarettes usually holds 20 individual sticks).

Up-conversion – 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. Up-conversion is an anti-Stokes type emission.

Vacuum-metallisation – A process to create a layer of metal on a substrate. Also referred to as ‘vacuum deposition’. It involves heating the metal target material until it vaporises inside a vacuum chamber. This allows the metal vapour to condensate and form a thin layer over the top of a substrate.

Variable printing – Using digital print processes to apply personalised and serialised information, such as unique identifiers and barcodes, to products and documents.

Vector graphics – 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.

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

Visible digital seal (VDS) – 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 a 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 such as an ID document or tax stamp.

Visible light – Wavelengths within the visible spectrum of 380nm-740nm.

Void label – Tamper-evident labels that, when removal is attempted, reveal a covert ‘VOID’ message. Also refers to anti-copy labels that, upon scanning, reveal the word ‘VOID’ in the copy.

Volume hologram – One of the most common types of hologram (together with surface relief holograms), these are mass-produced through optical copying of a master hologram, so they retain more of the optical properties of that master than the mechanical process of surface relief holograms. This allows them to be used for classical holograms which are fully 3D images, and they also allow the use of colour in the image.

Watermark – 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 item up to the light.

Wavelength – A property of electromagnetic radiation that denotes the distance between waves of light.

Wavelet transform – A mathematical means for performing a signal analysis when signal frequency varies over time.

Web printing process – 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.

Wet-glue application – The application of a coating of wet glue to a dry substrate before it is attached to an item. This is the main way of applying tax stamps to products.