If you’re overwhelmed by the vast number and types of optical features available to add security to identity documents, you’re not alone. In this series, a group of experts from the Secure Identity Alliance (SIA) will clarify the options—and when and how to apply them. This series is based on a paper presented by the SIA at the Optical & Digital Document Security (ODDS) 2024 conference in Lisbon, Portugal.
The authors began this series by reviewing the key concepts of optical features in identity documents. They then began an in-depth discussion of the science behind optical features. Here, they conclude the series with an in-depth and illustrated look at the various types of optical features.
Types of optical features
Colour-shifting features: Current colour-shift features can be sorted according to the technologies used as shown in the chart below (FIG 6):
FIG. 6: Colour-shift optical features by technical category
The right hand column covers colour-shift effects that are based on material and chemical properties, while the left-hand column covers effects based on physical structures. Table I below lists the types of colour-shift features used for ID documents. In the case of colour-shift features, they can be printed on any layer of the card construction visible from front or back and, for reasons of durability, they are always embedded within the latter.
Table I: Colour-Shifting Feature Types
IMAGE-SHIFTING FEATURES
Current image-shift features can be sorted according to the technologies used as shown in the chart below (FIG 7):
FIG 7: Image-shift optical features by technical category
Table II below lists the types of image-shift features used for ID documents and indicates where they may be placed within a card construction. Features applicable on the paper pages of a passport booklet are symbolized by the “booklet” icon.
Table II: Image-Shift Feature Types
Conclusions
Modern optical features for ID are based on a surprisingly small number of physical principles. They can be placed at different levels of a card construction and – if the features are well-selected – be distributed in such a way as to provide a very high degree of protection against tampering or counterfeiting while allowing visual authentication.
The increasing adoption of clear windows within ID document designs multiplies the possibilities for integrated optical features, requiring elements from different levels of the card to function. We can expect more elements of this type to be developed in the medium term.
While Identity is already largely digital, the last step in the chain of “trust” is still problematic when 100% certainty is needed to associate a physical person with a digital identity. One could argue that the State-owned ID document for which production and enrollment infrastructure has been painstakingly put in place over decades is perhaps the ideal bridge between the two worlds.
In conclusion, as long as humans have eyes, optical features will continue to be useful.
The present paper is published by the SIA and accompanies the roll-out of the eSEC 2.0 online tool for evaluation and comparison of ID document designs. The tool is intended for designers, integrators and document-issuers. For more information, please consult https://secureidentityalliance.org/ressources/esec
The Secure Identity Alliance (SIA) is an expert and globally recognised not-for-profit organisation. We bring together public, private and non-government organisations to foster international collaboration, help shape policy, provide technical guidance and share best practice in the implementation of identity programmes. Underpinning our work is the belief that unlocking the full power of identity is critical to enable people, economy and society to thrive.
Sources/References:
Yit-shun Leung Ki holds a PhD in Microengineering from the Swiss Federal Institute of Technology (EPFL). He has been active in the Security Print Industry for over twenty years and is currently with 4Plate GmbH. As an inventor of optical features, he likes to play with light.
Christophe Halopé has served as Executive Director of Crime Science Technology since 2019. Before, he served as Director of R&D at Arjowiggins Security, overseeing various business units, including Banknote, ID, Brand Protection, and managing the company’s IP. He also served as R&D Process Director at ASK (now Paragon ID). Christophe has a degree in chemical engineering and a master’s degree in industrial processes.
F. Daniel Françoise is an industry-recognized expert in Security Features for documents of value. After more than twenty years in senior positions at Hologram Industries/Surys /IN Group, she is currently the founder and director of PIKit an IP consultancy in the Paris region.
Renaud Laffont-Leenhardt is Senior Product Line Manager in the Identity & Biometric Solution Business Line of Thales, overseeing passport products, including secure embedded software, visual security features and issuance solutions/services. He joined Thales 28 years ago and has held various marketing and business positions in the government programs division for the past 21 years, notably handling business development in Africa and Latin America for secure electronic documents projects.
Robert Dvorak has been working on the development of optical security features since 2008. He has been participating in the implementation of DOVIDs into polymer banknotes and has developed a unique technology for the integration of optical security features into polycarbonate documents. His team is currently working on the development of materials that will enable a major increase in the complexity of optical protection of identity documents as well as banknotes.
Serge Wsevolojskoy, Idemia
Faten Ben Jemaa, Veridos
Maickel van Oijen has worked for 19 years in government positions at the Dutch Immigration Office and the Forgery Department at Schiphol Airport Amsterdam. He joined Keesing Technologies 8 years ago, where he now works as Manager Operations and Senior Document Expert, consulting on fraud cases and helping Keesing’s solutions evolve.
