Foiling, embossing and 2D, 3D holographic solutions

To be effective, and in order to act as a warning or precursor of the possibility that a product may be counterfeit it needs to carry easily recognizable, but secure characteristics, that can be identified as genuine by purchasers and those policing the distribution chain in order to root out fakes and diverted product.

In well balanced, secure counterfeit detection and deterrence systems, there will always be the presence of overt, covert and forensic technologies that are tasked with initial identification, secondary confirmation and finally forensic proof that may be used in legal challenges that require court action.

FOILING AND EMBOSSING

Foiling and embossing are both supplementary operations that are provided by printers to enhance a products appearance through its packaging or wet glue labeling.

Though it is not usual to see embossing on pressure-sensitive labels because the base material is not conducive to high degrees of pressure, it can be delivered through intaglio printing with the right material present and even simulated by silk screen processes that mimic the relief and tactility that makes embossing an attractive presence.

However, most embossing is carried out through the use of engraved dies (in male and female formats) that press (force) the paper from the front or back into shape.

The process is more effective on carton board than it is on paper and produces a cleaner edge to each design or letter of type that is transferred.

Embossing is a popular form of application for mandatory braille that is used on pharmaceutical product packaging to assist sight impaired citizens in identifying their medication. In these instances adding a further embossed verification decal simultaneously is a no-cost benefit.

TYPES OF EMBOSSING

There are different types of embossing process depending on the particular effect, image or design required and whether the embossing requires to be registered to prior letterpress, litho, flexo, screen or digital printing, or to hot or cold foiling. These different types of embossing process are summarized in Figure 7.2 and under the subsequent sub-headings:

Blind embossing. A blind emboss is embossing which has not been stamped over or registered with a printed image or with a foil. The color of the blind embossed image is the same as the color of the substrate surface. It can also be called a self-emboss or same color embossing.

Quite simply, by creating a raised area using a die, blind embossing is able to create a subtle paper colored image that can be felt as well as seen, offering both visual and tactile appeal. It is especially effective when a subtly elegant, three dimensional image is desired.

Different label materials, such as paper, film and foil, create different effects. So embossing can be a versatile option for creating a standout label.

Debossing. In this process, the substrate surface is depressed instead of raised as in conventional embossing.

De-bossing uses the same techniques as embossing to create the necessary indentation, except that the process involves the application of pressure to the face side of the substrate, forcing the material downwards into the female die so as to create the recessed profile. This can be as emphatic or delicate as the graphics or words dictate, and careful choice of substrate (avoiding bright whites and very smooth materials) will undoubtedly enhance the effect.

Registered embossing. Registration of one or more printed colors across the embossed area enhances the process further and makes it even more difficult to copy, replicate or scan.

Therefore embossing and registered print are seen as a basic defense against counterfeit attack and can be widely observed in use on the labels and cartons of wines and spirits seen on the shelves in supermarkets, liquor stores, duty free shops at airports and in bars worldwide.     

Combination embossing. Taken a step further, the addition of a hot or cold stamping foil in register with the embossed image is an effective method of deterring counterfeit attacks since the foil is impossible to replicate through copier attacks and scanning.

Combining the embossing with the foil means that any replication attempts that use a traditional print approach require the skills and the tooling to enable the attack to succeed.
 

The process of foil stamping (Figure 7.6) can be carried out either off-line (usual in sheet fed applications) or on-line (reel fed processes). In on-line applications this requires a special foiling station to be installed on the press that works in combination with the other printing and die-cutting units.

Tint embossing.  A relatively new method of embossing in which pearl or pastel foil is used in the embossing process. The methodology is the same as other types of embossing but the technique has become increasingly in demand. For tint embossing it is generally best to use white stock because pearl and pastel foils are transparent.

Micro embossing. This is where the effect is achieved with minimal depth but using intricate and complex designs. The process has become increasingly attractive in security applications such as event ticketing, anti-counterfeiting and legal documents. Indeed, embossing may be used for a wide range of security purposes.

Embossed seals or symbols of authenticity add security features to labels, government forms, legal documents, and corporate papers. Having said that, security embossing today is perhaps considered as an older form of document or label security, as more alternatives in analogue and digital print processes, origination and pre-press, foiling, etc., continue to be developed.

Glazing. This refers to a polished emboss. Glazing is a popular technique used on dark colored stock. The heat and the pressure when pressing the die are increased substantially. This adds shine to the surface. If a very high temperature is used, light color papers can be scorched to change the paper color. This provides for great contrasting designs if done properly.

As can be seen from the above summaries, there are many types of embossing to choose from depending on the embossing design created, the nature and type of substrate being used, the embossing effect required, whether the embossing is blind and raised or de-bossed and recessed, whether it is registered to prior printing or foiling.

A further embossing variation is die stamping, a method of printing and embossing the image using the same engraved steel or copper die. In this process, flatbed male and female dies are mounted in the same way as normal embossing dies and placed in a die-stamping press.

This press usually has a letterpress roller inking system which deposits a film of ink onto the surface of the female die. The substrate to be die stamped is positioned between the two dies which are then pressed together under extreme pressure leaving a printed and embossed raised image.

COMPOSITION OF FOILS USED IN PRODUCT PROTECTION APPLICATIONS      

Most stamping foils are comprised of five layers. The top layer (furthest away from the print substrate) is a polyester based film carrier. Under this top layer is a thin film of release coat which allows the release of the foil from its carrier when it is impacted by the die. Next is a lacquer or color coat that carries a pigment that gives the foil its color. This layer is transparent or translucent and provides color which can be matched to a specific shade if required.

The forth layer is the metal coat which is generally formed from metalized aluminum and this provides the reflective qualities and opacity required to prevent see-through from the material below. The final layer is an adhesive coat that provides the bond between the foil and the substrate.

HOLOGRAPHIC FOILS  

Holograms have found a useful application in securing print against unwanted copying and counterfeiting activity since the early 1980’s.

This is because holograms are a very useful overt recognition technology that can be adapted to each customer’s individual requirements.

The process has progressed over the years through simple 2D/3D designs which can be viewed as ‘entry’ level through to highly complex and counterfeit resistant designs that are continually evolving to combat the developing skills of the counterfeiter.

It needs to be recognised that security in print never stands still and is in continual competition with those who wish to compromise security devices and substrates.

Whilst there were only a handful of companies capable of producing holograms initially, this figure has grown to many hundreds today as universities and the growth of packaging and labeling in China and India drive the demand for holograms as a decorative feature as well as a security device.

Holographic products today can be separated into two distinct types, diffractive embossed optically variable image devices (DOVID’s Figure 7.7) and photopolymer filmic based technology.

Photopolymer (reflection) holograms are manufactured from photographic type film and were indeed the first forms of holography developed.

However, these early filmic devices were considered unsuitable for use in security printing applications because they were film based and needed to be coated with self-adhesives in order that they could be affixed to paper and board.

The process progressed further with the introduction of embossed holography which was more adaptable and could be applied in the same way as a traditional stamping foil.

Since the printing industry was more familiar with this type of application technology and photopolymer holograms at that time were considered unsuitable for anything other than artistic purposes, DOVID’s became the choice of many users who were faced with the challenge of protecting their labels and cartons from un-authorized coping and tampering.

Holography in embossed format relies upon the complex use of lasers and mirrors and lenses to record an image. Such images need to be originated just as conventional print requires origination too. Various origination techniques exist and some are more secure than others. 

Origination of embossed holography utilizes a sophisticated computer-driven system to create images in an embossing die that can be stepped and repeated to fit a narrow (or wide) web embossing machine.

Metalized foil (see above for foil structure) is passed through the embossing process (Figure 7.8 right) and the resultant finished multi-layered material is slit and delivered in rolls ready for application to labels and packaging using either off-line application processes or specialist in-line tooling (hot or cold foil blocking/transfer).

There are basically two types of holographic foil available to the designer, holographic patterned foil which offers a ‘wallpaper’ continuous repeating design (Figure 7.9) and bespoke registered holograms (Figure 7.11) which offer images that sit in isolation and must then be picked off the foil in registered with the print substrate.

Wallpaper or continuous type holograms are offered as stock items for separate foil application by the printer or already applied to paper and carton board for immediate conversion by those printers who do not already have a foiling capability. It should be noted that in ready applied form, holographic materials are have a total surface area of holographic coverage and this again limits their use mainly to decorative applications.

These continuous holographic stock products are not really secure and are often seen in applications such as toothpaste packaging and other personal care items such as shampoo and mouthwash.

The hologram’s main function here is to act as an eye catching design feature on the shop shelf rather than a security device.

It should be noted though such holograms are also available in stock foil format and can be used successfully used as a blocking foil in combination with a company logo die or as an embellishment to a blind embossing feature (Figure 7.10 right center of pack).

Bespoke registered holograms (Figure 7.11 Mercedes Benz illustration) are considered to be the most secure since they require the use of a registration mark in order that they are registered with the printing web and placed exactly in the same place on every piece of print produced.

This type of hologram requires careful design and accurate origination as it must be transported on the polyester carrier roll and placed exactly in position on a label or carton in order to provide conformity of product. Inexactly registered, or partially released holograms lead to uncertain authentication decisions later in the supply chain.

To prevent this from happening, each discrete hologram is produced with a corresponding registration mark aligned to its position on the carrier film. This registration mark is recognized by an optical read head placed on the foiling equipment and this automatically identifies the position of the hologram and activates the foiling head accordingly so the image is always placed in the correct position.

Such accuracy of production can only be obtained through the use of web inspection machinery similar to that used to control and identify print color registration on the press. Cameras are used to inspect each piece of foil, compare this with a pre-enrolled quality image and reject non-conforming product.  

Just as traditional security print can be protected from copy attacks by sophisticated design elements such as guilloche patterns and complex color registration, security holograms can be protected from unauthorized duplication by a range of in-built security design features. 

• CLR (Covert Laser Readable) Image – This is an invisible embossed mark that can reflect an incoming narrow laser beam (as seen in laser pen pointing devices) and project a recognizable image from the CLR source onto another nearby surface. Such images may be simple designs such as a logo or OK symbol.

• Concealed Images – These are images that can only be revealed when the embossed hologram is tilted towards or away from the viewer.

• Combi-Hologram – As its name implies this is a combination of origination technologies from different sources that combine to create one difficult to replicate image.

• Computer – synthetized 2D/3D – Embossed holography works through creating an image on a multi-planar surface similar to a reflector lens used in tail lights on automobiles. As the angle of view changes, light falling on the surface is diffracted giving the illusion of depth and movement.

• Guilloche patterns – In similar way to guilloche patterns used in traditional print origination these design devices create a complex series of intricate waves and radiating lines that change color and width when viewed at different angles.

• Kinetic Images (sometimes called Kinegrams® and Excelgrams®) – These images deliver parallax movement and bright dense color even when viewed at low levels of illumination. In more secure forms they are controlled and only seen on travel documents and banknotes. Tuned down versions that are suitable for brand protection are also available.

• Microtexts and Nanotexts – These act in the same manner as their analogue printing cousins. However microtext and nanotext in holographic form can change color and deliver kinetic movement from behind or from above another object such as a guilloche screen or logo.

• Stereograms – These are sophisticated, three dimensional holograms that combine a ‘live’ series of frames from a movie or moving model. Various views are shot and embedded in the origination providing an illusion of movement when the hologram is tilted or turned. Such images are impossible to replicate exactly since to achieve a satisfactory copy the counterfeiter needs access to the original movie or moving model.

• Security holographic foils continue to develop in the face of constant challenge from counterfeiters. This is because holograms are one of the most popular, and secure forms of authentication and provide all of the attributes necessary for accurate authentication (overt, covert, forensic). Therefore as their use widens in the fields of currency and ID protection and product security there will continue to be advances in new features and manufacturing processes in order to preserve the integrity of such devices.

More recent developments in this field include:

• Ultra-high resolution imaging – This kind of technology allows the creation of surface holograms with a resolution of up to 0.1 micrometers (254,000 dpi)

• Introduction of ‘pure’ white and black to white color switch – Up until recently it was not possible to deliver a ‘pure’ white to an embossed hologram. White light is a combination of all the prime colors and difficult to reconstruct using refraction gratings (which is the basis of a DOVID). Color switching from white through to black and all the corresponding gray scales between these two extremes provides a resilient, observable security feature.

• Custom pixels – Using ultra-high precision control, uniquely shaped pixels are micro-positioned to optimize the optical effect and provide an image that has a highly complex and recognizable forensic fingerprint. 

Security can be further improved by the introduction of track and trace numbering which is carried out using laser ablation, thermal transfer or direct permanent ink jet.

This process creates an image comprising a series of characters and/or letters making up a code that can be used to identify each unique hologram in the same way that banknotes each carry an individual number to identify each individual banknote (Figure 7.12).

The benefit of this process is that all production from each batch of holograms can be accounted for and audited to ensure there are no duplications or over runs in existence.

Further information on serial numbering and barcode application to embossed holograms is available here.

One important point though: the more complex the hologram the more difficult it is (time required) to be authenticated if multi-level overt, covert and forensic layers are introduced.

Using a few high level features at primary level so that quick visual confirmation is achieved is preferable to multifaceted hidden devices that require different tools to confirm their presence. 

All that is generally required for brand protection applications is one secondary system such as an encrypted barcode or laser activating (CLR) type images. If it is necessary to move to forensic approval then a taggant type approach where a molecular marker is incorporated in the body of the hologram adhesive layer is a practical solution. This latter step is only considered necessary for items of extreme value or for financial and identification systems.
    
TAMPER EVIDENCE AND DE-METALIZATION

There is a trend to incorporate holographic images into tamper evident labels, and this approach has merit when a carton or flexible bag needs to be sealed in a way that protects it from tampering and provides proof of first opening.

This is achieved by making the metalized holographic films frangible and introducing a tamper evident design into the adhesive layer (Figure 7.14) shows the effects of removal of a tamper evident holographic foil label).

When a permanent adhesive is used any attempt to remove the label results in an immediate deformation of the hologram and attempts to reseal the label will be evident. If edge cuts are placed around the circumference of the label these too act as an effective indicator of any previous un-authorized opening.   

Security for embossed holographic foiled images can be further increased by selectively de-metalizing the foil after the embossing process has been completed. This is a process much used in currency protection and applies a further skilled operation to the foil making it more secure.

De-metalized holograms can be seen on the UK £20 banknotes and on Euro banknotes above €50. The process allows for a much more intricate blocking configuration than that produced from a patterned blocking die and crisp images of micro-lettering and intricate border decorations can achieved that push the boundaries of successful copy attacks.

The effects of de-metalization can be seen on the image (Figure 7.15) from Holoptica. Note that the transfer of the image from the carrier web is completed without the need for a special patterned blocking die.   

SLEEVES, LIDDING FILMS, BLISTER PACKS AND TEAR TAPES

As a process, embossed holography is highly resourceful and has been applied to a variety of security tamper proof sealing technologies throughout the package goods market.

The technology can be seen in use on tear tapes for cigarette pack wrappers and in this form it provides a visual check of authenticity as well as a protection against pre-purchase opening and refilling of discarded packs.

In pharmaceutical packaging the use of holography on metalized blister packs provides similar protection by delivering a secure method of verifying that tablets or capsules within the blister container are real and in pristine condition.

Shrink sleeves are a further indication of the success of embossed metalized foils as they can be combined with the sophisticated shrink sleeves (Figure 7.16 shows how holography can be combined with the tamper evidence of a shrink sleeve) found in use on whisky, brandy and other high value spirit bottles.

Here they deliver a surety that a bottle has not been refilled, diluted or the product counterfeited.

Finally, when extended to the protection of heat seal lidding films, the process also provides similar protection to products carried in blow molded bottles and tubs such as lubricating oils, pharmaceutical tablets and other vulnerable products that require induction heat sealing.

In these instances it may be necessary to further barrier coat the film to ensure that cross contamination of the product is not an issue.       

INTRODUCING HOLOGRAPHIC EMBOSSING DIRECTLY ONTO PACKAGING COMPONENTS; PLASTICS, FLEXIBLE FILMS AND METALS

In certain situations it is possible to emboss holographic images directly onto packaging components such as clear reflective plastic cases and flexible packaging films as well as metal containers that are coated in a receptive lacquer that is capable of taking a finely embossed image and diffracting the incoming light in such a way that image becomes kinetic.

The process of creating a holographic image in clear plastic (Figure 7.17) is achieved by creating a specially embossed shim inserted into the injection molding tooling die used to produce each plastic component. The high pressure required to inject the material into the die results in the holographic pattern being transferred to the component during the molding process.

A similar process is undertaken to deliver an embossed holographic design to metal cans and containers where a lacquering process is used to coat the base metal after it has been printed and the coating exposed to engraved metal dies that implant the holographic image into the material creating the desired decorative/security effect.

Finally, work has recently been undertaken that moves away from the need for embossing tools to create holographic effects on clear flexible packaging films.

The images produce vibrant colors and seemingly moving images which allow observers to quickly identify the authenticity of a product to which an optical marker is affixed.

The technology works by using nano-scale ‘hole’ structures - smaller than the wavelength of light - to capture ambient light using ultra high optical efficiency and high pixel density. When such technology is applied to flexible wrapping or laminating film a bright background holographic image is produced that can quickly identify the origin of the material as secure.

PHOTOPOLYMER HOLOGRAMS

Photopolymer holograms depend on reflectance rather than refraction, (which is the process that delivers kinetic color movement for embossed holographic images). Photopolymer holograms are created in a photosensitive emulsion that is coated onto film in a similar manner to traditional photographic processing.

Reflection holography offers true color reproduction and all round 3D viewing when the device is tilted. The reflection process depends on highly complex chemistry, origination tooling in the form of special lasers, skill in setting up the holographic ‘shoot’ and the design of a suitably functioning device.

One of the main benefits of reflection holography is that there are only a small number of companies equipped to supply it as a security technology and a very limited number of suppliers of the base film used to reproduce the holographic image, which is exposed and ‘printed’ into the light-sensitive film coating in the same manner as traditional photographic films were printed before digital cameras were introduced.

This means that each image is exposed to the origination material, which is held on a clear photographic plate that is illuminated by a number of laser beams, and reproduced in a step and repeat process.

This allows each image to be superimposed with a further computer generated ‘variable’ image such as a number or other variable data (Figure 7.20 shows a clear unique reference added to each photopolymer hologram during the run of the original film) that can be used to create unique references that are able to be identified later and traced back to the original piece of film.

In the illustration above the security process is enhanced further by the addition of QR code that carries the same reference as the hologram on the tamper evident label construction affixed to the bottle and also to the carton behind.

Since every image is in fact unique and offers a true three dimensional view from each direction (front, rear, left, right) it is possible to introduce features into the design that can only be viewed from the front, rear, left side or right side of the image. This is a powerful anti-counterfeiting and authentication feature that is not available in any other holographic process.

When combined with serialization the process offers the highest levels of print-based security that exist at the moment.

The photopolymer holographic label (Figure 7.21) shows how the process can be combined with high security printing operations to offer both tamper evidence and authentication protection to a very high value computer component carton.

SOURCING SECURITY HOLOGRAMS

Holograms can be regarded as one of the most popular methods of securing labels and packaging from the unwanted attention of lawbreakers who may wish to make monetary gain by copying or diverting a brand. As has been revealed in this chapter, holograms are also useful in securing product against tampering and refilling fraud and if they carry further identification features in the form of track & trace numbering they fulfil all the security elements needed to protect and identify non-conforming product from fakes and adulterated replicas.

Because of their undoubted success in this field, holograms themselves inevitably attract the attention of counterfeiters and the sheer number of suppliers of embossed holography worldwide means that fakers are able to source similar if not exact copies of metalized DOVIDs easily via the internet. Indeed, just Googling the term ‘security hologram suppliers’ reveals 340,000 listings!

Many of these listings, and probably 90 per cent of them, are suppliers and distributors of stock holographic decals and foils that carry various misleading messages such as ‘genuine’, ‘OK’, ‘authentic’ and the like. Since anyone can purchase materials from such sites and then use these to pass off fake product as genuine, bona-fide suppliers need to offer much more secure designs that identify the brand owner and the product, as well as providing a traceable identification number for further security.

If designed and produced competently, a genuine security hologram is easy to identify when compared to a fake device. This process may not be so easy for the public to initially comprehend, but counterfeit holograms can be recognized straightforwardly by inspection teams that have been trained in distinguishing fake from real through just a few well-chosen identification features.

Note: To make the process of identifying fake holographic film suppliers easier for the industry, a register of bespoke security hologram designs was created in 1994 and this is policed by the members of the International Hologram Manufacturers Association (IHMA).

Members of this association are pledged to check with the register before taking on any new work to establish if the design they are being asked to produce already exists.

The register can’t 'police' the activities of non-members, but over the years it has contributed to the detection of copied holograms and even to the apprehension and prosecution of the criminals behind them.

Therefore there is a responsibility for everyone involved in this area of security packaging and labeling to ensure that they supply or purchase from bona-fide, trusted sources and they carry out due diligence before they enter into new supply arrangements.

If you are a packaging supplier or holographic foil manufacturer this means checking that a brand owner is who he says he is before proceeding.

Cases where criminals pose as recognized brand owners, wishing to purchase ‘genuine’ packaging and labeling supplies, for use in counterfeit scams are regularly being uncovered, so it’s not just a case of caveat emptor or buyer beware – it’s ‘supplier beware’ too.