For authorities worldwide, the fight to protect passports against fraud remains as intense as ever.

Of course, the rapid adoption of electronic passports over recent years has proved a major step forward in terms of both homeland security and traveller convenience. 

There's also fast-growing recognition of what polycarbonate data pages can do in thwarting attempts to tamper with or counterfeit passports.

high security printing for passport  

Security printing techniques in 2020​

However, we believe it's key that authorities do not overlook in 2020 the importance of a security-conscious approach to the paper elements of a passport's design and production. After all, paper pages still make up the bulk of the document.

What's more, they include the cover and end pages (glued to the inside of the cover), as well as the pages that hold the visa and entry and exit stamps. And for those that have not yet migrated to polycarbonate, paper will also form the basis of the all-important data page, which includes the holder's details and portrait.

To maintain an effective defence against the menace of counterfeiting, all these paper elements need to be given careful consideration. 

As ever, success will ultimately lie in making it as complicated, time-consuming and expensive as possible for forgers to copy or compromise a legitimate document.

The good news for 2020?

A host of proven high-security printing techniques are available that will help to deter even the most determined and resourceful criminals when designing a passport in 2020.

In this article, we'll once again be slapping on our lab coats. 

We'll be providing readers with an expert guide on how best to use the paper elements to protect the integrity of what is, after all, a vital national asset.

In particular, we'll be posing a simple question: how can security printers such as Thales design the paper elements of a passport to make it much harder for counterfeiters to copy or imitate a document's visual aspect?

In line with the fundamental principles of any secure passport design, we'll find that the answer ultimately lies in the effective combination of a range of different techniques. Specifically, these include:

  • Employing technologies that are difficult to copy.
  • Incorporating multiple security features - so a counterfeiter will need to master them all to stand any chance of success.
  • Using materials, technologies, inks, and components that are difficult for criminals to source. 
  • Using inks and components that are only sold to secure printers.

Now let's look in detail at some of the techniques that can enhance the security of not just the paper elements, but the passport as a whole. We'll also consider how specific threats are countered by Thales' field-proven security features and processes.

Let's start at the end…

Passport end pages

End pages play a critical role in protecting the integrity of the whole passport booklet.

Access to the stitching – and hence the data page – should be prevented through the use of high-security printing methods on a secure paper substrate. This should be fully bonded and secured to the cover material.

Passport numbers

High on the list of assets that can be utilized in the fight against counterfeiting is a document's unique passport number. When a lost or stolen document is reported to the police, this will typically end up on an international watch-list such as the one maintained by Interpol. Inevitably, fraudsters will attempt to change one or more of the digits, to try and ensure that the authorities are not alerted when the document is presented at a border checkpoint.

passport number  As well as the size, Thales can even vary the basic hole shapes forming the passport number - including circles, squares and/or stars, for example.

Effective endpaper design will, therefore, include burning the genuine document number through every single page, using laser technology. This means going through all the visa pages, as well as the back cover. 

These numbers comprise small conical holes, the size of which varies according to the page number, making it even harder for counterfeiters to swap pages.

Intaglio printing: another powerful security tool (process)​​

A security printing technique known as Intaglio printing provides another powerful security tool. At Thales, it typically incorporates latent images that can only be seen when viewed at particular angles. 

Furthermore, Intaglio printing has a distinctive feel to it. This is immediately recognizable not just to those responsible for checking the document's authenticity, but the wider public too.

This familiarity reflects the fact that Intaglio is a long-established security printing technique, used not just for passports, but banknotes too.

Intaglio printingIntaglio printing can create tactile effects.

Which process best describes intaglio printing?

  • The lines to be printed are cut into a metal plate through an etching process. 
  • The ink is applied to the surface of the plate and pushed in the recessed lines. 
  • A rolling press is then used to apply very high pressure to push the paper into the recessed lines. 
  • The area that prints is below the surface of the plate. 

This creates a unique effect that is very difficult for counterfeiters to replicate: it requires specialized skills and dedicated equipment. It can also be checked easily, only by running a finger over the printed page.

According to the Keesing Journal​ of documents &Identity of June 2017, Intaglio remains a technique that cannot be replaced by inkjet or toner printing, at least for now. It is also barely accessible to counterfeiters. Tactile effects, in particular, are hard to reproduce.

Intaglio continues to offer a high level of security compared to digital printing.

And the security struggle doesn't stop there…

Anti-copying elements

In addition to intaglio printing, endpaper print design can employ several additional anti-copy elements. These include offset printing in four colours and UV 365 in two colours, as well as IR reactive inks

Intricate design patterns will pose further challenges for fraudsters.

passport printingSee here a detail of the cover page of the Swedish passport under UV light. Front and backlights of cars on the roads only appear under UV and create an amazing effect.

Ultra-thin security paper

Thin endpapers (no more than 85gsm) represent yet another asset for passport issuers.

In that case, being fragile is a strength.

Because the volume of adhesive needed to bond the cover, combined with the calendaring effect of Intaglio print, means that counterfeiting attempts will be prone to glue seepage and staining. Crucially, Thales can produce ultra-thin endpapers that are as durable in operation as they are fragile if attacked.

If a forger does try to separate the endpaper from the cover, it will be destroyed and rendered useless.

passport paperBelgian and Swedish passport front covers are shown here. With the special embossing, removing the thin inside cover paper is almost impossible.

Solid bond: benefits of the moiré printing

​​As if all the above wasn't enough, consider a few more of the endpaper techniques that Thales employs on behalf of passport issuers:

  • Special high-security papers that contain visible and/or invisible fibres, according to individual customer requirements.
  • Bonding to the embossed cover material that ensures there are no bubbles or creases on the end page.
  • Tiny laser-produced holes of various shapes that make up the document's serial number, visible through both the cover and endpaper. Any attempt to delaminate and re-use the endpaper will be immediately evident because the holes cannot be realigned.
  • Endpaper aligned perfectly to the cover material, defending against the addition of a counterfeit.
  • Thales further reduces the risk of counterfeiting by using a material that features a unique, highly detailed embossing registered to the document. If split, it leaves air gaps, and the end pages will not lie flat. Also, the inside front cover incorporates a letterpress serial number reproduced using specialist inks.

Therefore all the pages are numbered securely. 

This process is difficult to replicate without specialist equipment; attempts to do so are recognized easily by border guards. Finally, Thales proposes a Moiré movement print effect. This is a visual effect that occurs when looking at a set of lines or dots suspended over another set of lines or dots. In this case, it is suspended over pre-embossed lines behind the print.

Moiré printingMoiré printing creates a wave effect when tilted on the 2017 Finnish e-passport

Visa pages

Now let's turn to the visa pages

Intaglio print

What's the best way to resist attempts to counterfeit these?

The Thales design studio utilizes the latest print security software to produce technically challenging and difficult to copy designs. The aim is to ensure that pages cannot be moved to hide a travel history or official endorsements, or transferred from one document to another. For the visa pages, specific design elements available include security printing and cross-page designs.

Cross-page design​

The inclusion of a cross-page design means that a forger trying to replace a single page would need to match up all the visible and invisible elements on a substrate that held the same level of UV reflectance.

Each page is a single sheet that passes through the central stitching. It is further locked down at this point, making extraction difficult.

cross page design as passport page numbering

Count on page numbering…

As we've already highlighted, Thales delivers passports with pages that are numbered consecutively throughout the booklet. It's an obvious way of providing reassurance that pages have not been removed to hide the holder's travel history. 

There's more.

These numbers are incorporated within both the visible and invisible design when illuminated with UV at 365nm. They're also in offset print and incorporated into the design using bi-focusing lines, deliberate errors, and see-through print register in at least three colours.

Bank on see-through for high-security printing​

'See-through'​ is a design motif made up of two parts. One image is printed on the front, the other in precise register on the reverse of the data page/visa page. Under transmitted light, both models become visible, creating a complete element.

This feature has been present in most banknotes for many years. It is adequate protection against copying since it requires a specific machine that is sold only to high-security printers. This enables printing simultaneously on both sides of the paper. 

Counterfeiters, in contrast, will need to print one side of a page before flipping it over and printing on the reverse.  This results in a blurry image – fraudsters simply cannot achieve a perfect alignment with the equipment that is available to them.

Special security printing inks and layers

​Remember, the ultimate aim is to make it so tricky, time-consuming, and expensive for a counterfeiter to replicate a passport that it simply isn't worth their while to try.

UV sensitive fibers in the papers of pasportThis illustration shows the Estonian ePassport under UV lighting. The document integrates invisible yellow, blue, and red inks and UV-sensitive fibres in the papers. These fibres are approximately 3mm long and 25 decitex thick (10,000 m of thread weighs 25g).

At Thales, we, therefore, add even more layers of complexity:

  • Close alignment of the print and cross-page designs makes the removal of a single page more difficult.
  • Microprinting and nano text, along with multiplex printing, make replication still more challenging.
  • All visa pages are printed on security paper that has no optical brightener.  
  • Designs incorporate at least four colours and are rainbow printed.
  • Special security printing inks used are IR reflective or absorbent – but look identical in white light.
  • Thales also uses randomly distributed, visible, and invisible fibres, plus candy-striped fibres, all of which can react to long-wave (365nm) UV light. Furthermore, specific fibres have a multi-UV reaction, which will fluoresce in two different colours, helping to authenticate the legitimacy of the substrate.
  • Fibres are inserted during the paper manufacturing process and appear randomly across the paper. Counterfeiters often simulate such visible and invisible fibres using printing techniques, but in doing so, they tend to drop the random patterns. Consequently, similar patterns on more than one page of a passport are a sure sign that something suspicious is going on.

Fibers and multi-color UV reactive fibersFibres can also have a multi-colour UV reaction.

Watermark: an essential element of robust passport design

​Commonly used in banks and stamps, the watermark is probably the most widely recognized secure printing feature of them all. And it remains a crucial element of robust passport design.

Watermark incorporated in the paper The watermarks are a Level 1 feature -visible to the naked eye - incorporated during the papermaking process using a mould specific to the customer's design. When viewed by transmitted light, it appears as various shades of light and dark, caused by density variations in the paper.

For visa pages, Thales employs a multi-toned cylinder mould watermark registered to the design. To ensure optimum visibility, it is usually positioned in a reveal area. Also deployed is an electrotype or bright watermark that is identical on every visa page. 

This can be used to provide additional information, such as page numbering.

More tell-tale signs of counterfeiting…
Watermarks are best viewed by holding the document up to the light or shining one through the paper. It is easy to verify, as a genuine watermark never reacts under UV light. A chemically simulated one, however, is likely to respond, providing another tell-tale sign of counterfeiting.  

Embedded security threads in visa pages

​In some of the passports it produces, Thales inserts security threads into the visa pages. 

Just like those used in banknotes, these are embedded directly into the paper during manufacturing. 

They can be made from either plastic or metal, with customer-specific designs and covered by the paper or 'windowed' (i.e. visible on the surface of the window at regular intervals).

A windowed thread can be seen below under UV and normal light, in the Swedish passport. This plastic security thread inserted in the paper features a visual effect whereby images of airplanes are seen to be moving in the opposite direction when the thread is tilted.

Security threads into the visa pagesPlastic security threads into the visa pages
 We’re not through yet

Edge design in visa pages

Edge design is also used in the fight against counterfeiting of visa pages. Thales prints a different part of the edge of each page. 

When viewed edge-on and the pages are spread, these form words in offset print. Seen from the opposite side, UV characters are visible. Each page has floating and static pages numbers, in both visible and UV printing.

UV printingHigh-security printing is visible at the edge – under normal light and UV light.

Chemical secure printing processes 

Generally, there are only two main ways to remove an endorsement from a passport:

  1. Abrading the endorsement away or scratching it off with a scalpel
  2. Finding the correct solvent to dissolve the endorsement

For the latter approach, finding the right chemical is always likely to be difficult for a potential counterfeiter. Even then, pigmented indelible inks cannot easily be removed from the substrate. There will almost always be a trace left behind, which can be seen under UV or IR light, or through damage to the paper fibres.

Water-based inks are easier to remove: border control authorities should, therefore, ensure that the inks they use for control purposes are indelible, or contain elements (such as UV reaction) that make them unique. 

However, such an approach cannot be guaranteed, and the threat of modification must be countered by secure printing processes and unique substrate and reagents within the paper that are sensitive to chemical attack.

Many of the techniques already detailed in this article will make any such attempts apparent. Watermarks, for example, will become severely degraded or damaged, should the page be split or abraded.

Furthermore, Thales' security paper contains chemical sensitizers that react to solvents. As a result, if a chemical is used to remove a visa sticker or border entry/exit stamp, the reagents are activated, leaving a visible stain on the page.

Solvents would also damage the offset and UV elements, causing them to deteriorate. Besides, the base fluorescence around the affected area would change and become brighter. 

Passport stitching and sewing

End pages play an essential role in protecting against access to the stitching, and hence the data page by fraudsters. In this article, we've already outlined how processes such as high-security printing, bonding, and the use of ultra-thin paper make counterfeiting extremely difficult.

But we also use very fine sewing threads to secure the booklet pages to the end pages and covers. A combination of different materials and colours further guards against dismantling and reassembly.

During manufacture, an automated system uses a consistent process to sew each passport individually, to the same specification, using three different strands of high-security thread. These are pulled and twisted, giving an equal number of turns between each hole. 

The top and bottom three stitches are back stitched and held in place with a locking stitch.

Sewing threads to secure paper against counterfeiting

This is further sealed with spine tape containing a heat reactive adhesive that makes re-use of the thread impossible.

All stitch segments are of equal length. As the thread is made up of discrete strands, if dismantled they separate easily.

You bet: this makes re-use extremely difficult, and any attempt at dismantling is readily identifiable.

Stitching - passport papers

Cover Material as a security element for printing

Finally, we've got the cover covered too…

We use a latex saturated cover material. As already described, this is fully bonded with a combination of adhesives that adhere to the cover and end pages to the passport permanently. The passport is stiff enough to lay flat, yet flexible enough to permit secure bonding to the end pages.

The overall lesson of secure passport papers techniques and design

Over recent years, attention has inevitably focused on breakthrough technologies such as ICAO compliant embedded software and protection mechanisms (EAC, SAC).

But it is equally crucial that secure software, and new materials such as polycarbonate data pages, are not regarded as some form of "magic bullet".

Truly secure passport design is very much the sum of its parts, and that still includes a significant paper element. Above all else, what we have aimed to emphasize in this article is that features such as end and visa pages are still high on the hit list for counterfeiters. 

Equally, there is a multitude of security tools at the disposal of passport printers and their customers to fight document fraud​.

As a result, with security printing techniques, it is entirely possible to deter even the most sophisticated efforts to modify and replicate genuine documentation.

Any such attacks will be immediately apparent to border control staff (equipped with or without a document reader) and other law enforcement bodies.

How can we help you design a highly secure passport?

Thales has acquired in-depth know-how on paper technologies as it has been delivering passports and ePassports since 1987. The company has an even more extended history of security printing activities, including banknotes, stamps, and bonds dating back to 1885.

Highly Passport security print

At Thales, we believe in taking a comprehensive approach to security. That's why we strive to provide secure, durable, and innovative solutions.

We're proud to have succeeded in designing some of the most secure and attractive passports, IDs and driver licenses to appear in recent years.

If you need more information on passport security design and the one block concept, visit our report Anatomy of a secure travel document.

Understand why authorities more and more select a polycarbonate data page.

Now it's your turn

Do you think paper still matters too?

If you've something to say on passport security design and paper elements, in particular, a question to ask, or have simply found this article useful, please let us know. 

We'd also welcome any suggestions on how it could be improved or proposals for future articles. 

We look forward to hearing from you.