Joel Zlotnick, Tyra McConnell and Traci Moran
Counterfeit Deterrence Laboratory
Office of Fraud Prevention Programmes
Bureau of Consular Affairs
US Department of State
Microprinting is primarily a security feature intended to combat digital counterfeiting, but it can also be optimised for other purposes. Part 1 and Part 2 of this series have explored the optimisation of microprinting artwork and colour, including ways that microprinting can combat sophisticated traditional counterfeiting while continuing to fulfil its conventional role against digital counterfeiting. This third microprinting article shifts focus from counterfeit resistance to user ergonomics and alteration resistance. Although ergonomics and alteration resistance are different topics, both relate to where microprinting is placed within a complete security document.
In the case of user ergonomics, a significant limitation of microprinting is that it can be hard to locate and inspect. To mitigate this disadvantage, predictable microprinting placement and the inclusion of cues to alert document users to the presence and location of microprinting can make it more accessible.
For alteration resistance, offset or intaglio microprinting can be intersected with security features, bearer portraits, personalisation data or even letterpress serial numbers to provide evidence of tampering if these features are eradicated or changed.
Throughout this article, microprinting graphics (Figures 1 through 33) are displayed in pairs, with the left image captured at lower magnification to show context in the document and the right image at higher magnification to show greater detail. The strategies described are presented for informational purposes and may or may not be appropriate for specific security document applications or manufacturable by all security printers.
Single microprinting lines
Many of the microprinting artwork customisation techniques described in the first part of this series are most flexible when applied to larger microprinting patterns, but single lines of microprinting are often used where space is limited. One of the most typical placements for single lines of microprinting is at the edges of border designs as in Figures 1 and 2. To make the microprinting further stand out it can also be isolated from other artwork as in Figures 3 and 4. Although the microprinting still cannot be read without magnification, the single thin line might be seen more easily and may alert (or remind) document users where the microprinting is located prior to magnification.
The documents in Figures 3 and 4 are banknotes that do not contain personalisation data, but microprinting is often included in one or more format or signature lines in birth certificates, passports and visas adjacent to locations that contain handwritten or printed bearer personalisation data. For example, Figure 5 shows microprinting in the signature line of a passport and Figure 6 shows microprinting in the format lines of a visa. These not only guide document users to locations where microprinting can be inspected but can also help expose alterations, which will be discussed in greater detail later. The single straight lines shown in Figures 1 through 6 provide limited opportunities for customisation of the microprinting pattern, but font customisation, multi-plate offset or multi-depth intaglio techniques as described in earlier parts of this series could still be applied.
Multi-line microprinting patterns
Prior examples described some placements that make single microprinting lines easier for document users to locate, but multi-line microprinting patterns may be easier to see because they are larger and also offer more opportunities for customisation. Just like single lines of microprinting, multi-line microprinting patterns can be isolated from competing artwork and placed at edges or borders to make them easier to find, as in Figures 7 and 8.
Macro document artwork can also be used to alert document users to the presence and location of microprinting. Books, scrolls, plaques and monuments are thematic elements that document users may naturally associate with text. For example, the macro artwork of Figure 9 includes a book, with the text on its pages integrated as microprinting. Similarly, the text on the side of the monument in Figure 10 is actually microprinting.
In Figures 9 and 10 the non-text macro artwork helps document users anticipate the placement of microprinting, but design of text patterns alone might achieve the same thing without assistance from the macro artwork. As an example, Figure 11 shows six rows of text of different sizes. The upper rows contain larger text and can be read without magnification. Further, even without magnification document users can easily see that each lower row contains text of progressively smaller size. The readable top rows can draw attention and alert users to the presence of smaller microprinting in the lower rows. Figures 12 and 13 show similar implementations of multi-size text with the same result. The strategies shown in Figures 11 through 13 are one reason this series has made no effort to objectively define how small text must be before it becomes microprinting; these examples show that there can be advantages to microprinting patterns that include text of multiple sizes.
The examples in Figures 7 through 13 pertain to drawing user attention to discrete regions of microprinting, but another placement strategy is to incorporate microprinting throughout the entire background artwork. This occupies more surface real estate but makes it easy for document users to locate microprinting since it can be found anywhere. Examples of full-page microprinting designs are shown in a passport in Figure 14 and a stock certificate in Figure 15.
Microprinting and security halftones
Large microprinting patterns that contain repeating artwork can be at risk for step-and-repeat traditional counterfeiting. One way to make large microprinting designs more resistant to step-and-repeat counterfeiting is to incorporate microprinting in a security halftone. Halftones simulate a wide gamut of densities in a macro image by dynamically changing line width across a microscopic line art design, producing two distinct images with and without magnification. While typical halftones used in commercial printing are usually dot patterns, halftones in security artwork can be based on semi-randomised microscopic line art, such as geometric elements as in Figure 16, microprinting alone as in Figure 17 or a combination of shapes and microprinting text as in Figure 18. Security halftones were described in prior work and will not be examined in detail here, except to note that such halftones can be a vehicle for introducing microprinting into large areas of artwork.
Whether a security halftone should contain graphics, text or both might be decided based on document user training considerations and other factors. Any artwork in Figures 16 through 18 would be tedious and time-consuming for a traditional counterfeiter to replicate since step-and-repeat processes are difficult if every individual shape or character features its own unique set of line widths. However, microprinting may be different from other types of security document artwork in that lay document users might more easily determine whether pure text is readable but may not be as comfortable assessing a security halftone composed only of shapes. If this is true, security halftones containing or based entirely on microprinting might have advantages. On the other hand, security halftones are complex and microprinting might be more understandable to lay document users in a simpler all-microprinting line or pattern that does not also contain non-text shapes that compete for user attention. The question will not be resolved here; as with all other content in this paper, whether microprinting belongs in a security halftone, or in other artwork elements, or both, is a matter for issuer discretion.
Multi-plate and multi-process microprinting
Since each printing plate and/or manufacturing process used in a genuine document contains its own unique artwork, each plate design represents a fresh opportunity to incorporate microprinting. It is common for every printing plate in a security document to contain microprinting, but in most cases the microprinting is in different locations and users must search for it. For improved ergonomics, some of the microprinting from multiple plate images can be clustered in the same microscopic area to facilitate simultaneous inspection. Some examples featuring four colours of microprinting in the same location are shown in Figure 19. In Figure 19 the microprinting is offset and intaglio print, but microprinting can also be included in other processes and features like plastic substrate lamination plates as in Figure 20, optically variable devices as in Figure 21, and more.
Placement in similar documents
Some conventions exist for microprinting placement in similar documents. Similar documents could be all the visa pages in the same passport book, multiple denominations in a banknote series or another example of two or more documents from the same issuer that might be expected to look alike. In these examples, microprinting placement is usually related to better user ergonomics but can also contribute to alteration resistance in some circumstances.
Consider the three passport pages in Figure 22. In each page, the location of the microprinting is consistent, making it easier for document users to inspect it throughout the book. Likewise, the placement of microprinting at the same edge in each of the three banknote denominations in Figure 23 makes it easier for banknote users to find it.
Microprinting and alteration resistance
Earlier articles in this series described strategies for microprinting resistant to both digital and traditional counterfeiting but did not address microprinting and document alteration. Protecting against alterations is a complex topic that exceeds the scope of this article because chemical and mechanical alterations require different defences, various document types are subject to different alteration attacks and multiple classes of anti-alteration security features are involved. But as with ergonomics, deliberate placement of microprinting can facilitate better document alteration resistance.
In many cases, the element to be protected from alteration is applied over continuous offset or intaglio artwork. In truth other kinds of security line art can be used for the background, but these examples focus on microprinting. Examples include serial numbers as in Figure 24, bearer signatures as in Figure 25, inkjet or other digital personalisation text data as in Figure 26. Portraits are also commonly protected by application over a microprinting pattern, which can be printed in visible ink as in Figure 27 or with invisible UV-reactive ink as in Figure 28. In all of these examples, tampering with the protected feature risks damaging the continuity of the underlying microprinting (or other artwork) pattern, which contains details sufficiently small that counterfeiters could have difficulty restoring them if interrupted.
In other examples, static microprinting is applied over certain document components to help bind them more closely to a specific host document. These include offset or intaglio microprinting applied over the edges of optically variable devices (OVDs, a holographic security feature) as in Figure 29 or a windowed security thread as in Figure 30. The microprinting patterns in Figure 29 and 30 are smooth and continuous across the edges of the features, and discontinuity or interruption could indicate an alteration. Similar overlap strategies can be applied to a variety of other document components.
One way that changeable data can be secured against alteration is redundancy, and microprinting is one way to introduce redundancy. The passports shown in Figures 31 and 32 contain laser engraved microprinting that includes the bearer’s personal data. Most static line art microprinting in security documents is intended to combat counterfeiting. In contrast, this personalised microprinting plays roles both in anti-counterfeiting (because its small size is a product of the laser engraving process that may be hard for counterfeiters to mimic) and anti-alteration (because it can be compared to larger duplicate text data printed elsewhere in the document).
Similarly, microprinting can be incorporated in secondary portraits, such as the inkjet secondary portrait in Figure 33 that incorporates the bearer’s unique personal data. Inkjet microprinting in a genuine document may be surprising since inkjet is often regarded as a tool for counterfeiting. However, in this application the anti-counterfeiting value is defined less by the resolution of the inkjet printer than by the software that generates the hybrid secondary portrait based on both the bearer’s face (macro image) and bearer’s personal data (micro image). As with all secondary portraits the example in Figure 33 can be compared with the primary portrait, so a counterfeiter would have to change both to produce a convincing alteration.
Although microprinting is not the solution to every document fraud problem, it remains a tremendously flexible design feature that can be optimised at relatively low cost to fill both primary and ancillary security roles. As the third and final instalment of a series concerning microprinting, this article has explored how microprinting placement can impact both user ergonomics and alteration resistance. Prior articles in this series have explored microprinting in terms of font and pattern design, ink selection and colour gamut, genuine issuer press capabilities and the importance of both resolution and registration in combating both digital and traditional counterfeiting. Issuers are encouraged to consider all of these facets of microprinting together, since combining all of the techniques presented throughout this series – artwork, colour and placement – may provide a pathway towards maximising the value of a microprinting design to improve document security without driving up costs.
MORE ABOUT THE AUTHORS
Joel Zlotnick is employed by the US Department of State, Bureau of Consular Affairs, Counterfeit Deterrence Laboratory as a physical scientist. He conducts research on how design strategies can help maximise the security value of printing technologies and security features, and develops training programmes on counterfeit detection.
Tyra McConnell is a Forensic Document Examiner at the US Department of State, Bureau of Consular Affairs, Counterfeit Deterrence Laboratory. She provides training on security documents and develops presentations and e-learning courses regarding counterfeit detection.
Traci Moran is employed by the US Department of State, Bureau of Consular Affairs, Counterfeit Deterrence Laboratory as a physical scientist. She conducts research on security documents and delivers counterfeit detection training to varied audiences.
Disclaimer: This document represents the opinions of its authors and not necessarily the opinions of the US government. The technologies and strategies described may not be available, appropriate or manufacturable for all document issuers. The examples shown do not imply anything about the quality of a document, its designer, its manufacturer, or the issuing authority. For informational purposes only.