Holograms as Security Features: Origination, Development, and Perception
As anti-counterfeiting features, holograms are present on various products,
from banknotes and credit cards to children’s strollers. Most people
encounter them every day, yet they are often unaware of their presence.
Holograms are subject to continuous research and development and are more
recently known in the form of projections. They are even considered
futuristic art by some.
The invention of holography tells a long story of research that is based on fundamental laws of physics and optics. Like photography, holography is a way of recording, yet the technologies have substantial differences when it comes to the information captured. As the meaning of the Greek words “holo” (whole) and “gram” (message) connote, a hologram captures the entirety of a scene, with all its visual properties, including the realism of three dimensions.
The invention of holography tells a long story of research that is based on fundamental laws of physics and optics. Like photography, holography is a way of recording, yet the technologies have substantial differences when it comes to the information captured. As the meaning of the Greek words “holo” (whole) and “gram” (message) connote, a hologram captures the entirety of a scene, with all its visual properties, including the realism of three dimensions.
Technology and history
Holographic security elements consist of nanostructures that refract light in a
very specific manner. They enable 3D effects to be seen on what appears to be a
flat surface. These structures can be originated by means of classical (analog)
holography, where — comparable to classical photography — a photosensitive
material is used for recording light. Similarly, a hologram is created by
recording the interference patterns created by lightwaves. To form such patterns,
two wavefronts must interfere, which is only possible if the wavefronts are
coherent. To guarantee coherence for a specific length, the beam of a single laser
is split into two coherent beams. To record a hologram, a system with various
optical elements must be set up in a carefully measured manner under specific
laboratory conditions: particle-free with high stability (no vibration) and
consistent air temperature
Figure 1. A laser setup on an optical table for classical (analog) hologram
origination. Courtesy of 3D AG
The roots of holography can be traced back to 1920’s research in x-ray
crystallography. The idea for holographic imaging was invented by Denis Gabor
in 1947 while he was trying to obtain increased resolution in electron
microscopy. His work proved the concept’s validity. Optical holography was not
yet successful, however, due to poor quality. The reconstructed image was
superimposed on a background, caused by a conjugate image and direct beam. The
breakthrough that solved this twin-image problem was an off-axis reference beam
technique invented in 1962 by Emmett N. Leith and Juris Upatnieks. Then, with
the invention of the laser in the early 1960s, holography had its breakthrough
and the technology opened to wide research, resulting in the creation of new
techniques of design and types of holograms
For several decades, analog optical procedures were the only methods available for
creating nanostructures with holographic effects. Advancements in digital
technologies in the late 1980s enabled the origination of computer-generated
holograms, for which the first patent was filed in 1988. This breakthrough led to
the development and invention of various proprietary and commercially available
systems. Following the trend of multiple applications of holographic structures,
some companies chose to develop their own methods and keep their systems in-house.
Others started businesses and sold their systems, such as the KineMax, or
variations of the relatively simple and in In comparison to the expensive,
sophisticated, and difficult-to-operate e-beam systems, which were traditionally
used by large research centers and universities, the inexpensive dot matrix
systems required minimal training to use. The increase of dot matrix technology
enabled a wider range of companies to originate holograms and therefore to replace
expert holographers. At least 100 dot matrix systems are now used worldwide, which
has resulted in greater accessibility but has also increased imitations and the
number of counterfeiters abusing security features. Additionally, while holograms
were establishing for security uses, they also became decorative features for
promotional and packaging applications, allowing use to spread even more widely.
At the beginning of the century, the rapid development of digital technology
had increased the availability of holograms but decreased general trust in
them. Over the past decade, a time of globalization and spread of online
channels, the need for security features for anticounterfeiting has
exponentially risen. Packaging and products are equipped with
anti-counterfeiting features that are both overt (effects visible to the human
eye) and covert (elements such as nanotext and hidden features visible only
with tools) for consumer
authentication, as well as for controlling the distribution chain. Because of the
current high demand for solutions, other technologies have developed, especially
smart and digital features, such as unique QR (quick response) codes and RFID/NFC
(radio frequency identification and near-field communication)
Today, the earlier negative associations with holograms seem to have faded.
Holograms remain one of the few valid solutions for true authentication that can
implement both overt and covert features, serialization, and smart solutions used
for consumer engagement and tracking. With their presence on banknotes, holograms
still convey a sense of protection and security in comparison to unknown and newly
developed digital solutions. Additionally, holography companies use their specific
technology to regularly develop new features such as machine readablity, covert
hidden features, or visual enhancements.
When it comes to the benefits and limitations of the technologies, results show analog holography and e-beam lithography to be more suitable for security applications due to their higher implementation cost and lower availability (Table 1). For every anti-counterfeiting solution with a specifically implemented technology, however, the cost of education is high because the implemented solution needs to be communicated to the general public and to the distribution chain. Both analog holography and e-beam systems are able to facilitate this education and level of security better because they come without pixels, with a high resolution, and with some effects untouched by the digital holography technologies.
When it comes to the benefits and limitations of the technologies, results show analog holography and e-beam lithography to be more suitable for security applications due to their higher implementation cost and lower availability (Table 1). For every anti-counterfeiting solution with a specifically implemented technology, however, the cost of education is high because the implemented solution needs to be communicated to the general public and to the distribution chain. Both analog holography and e-beam systems are able to facilitate this education and level of security better because they come without pixels, with a high resolution, and with some effects untouched by the digital holography technologies.
Table 1.
A summary and comparison of the main types of holographic nanostructure origination techniques
A summary and comparison of the main types of holographic nanostructure origination techniques
Size
Thickness
Film direction
Inner Core
Packaging
82.6X51mm
15-16um
Vertical horizontal input
3 Inches core Or customized core
200pcs/Roll White box packaging
82.6X51mm
15-16um
Vertical horizontal input
3 Inches core Or customized core
200pcs/Roll White box packaging
82.6X51mm
15-16um
Vertical horizontal input
3 Inches core Or customized core
200pcs/Roll White box packaging
82.6X51mm
15-16um
Vertical horizontal input
3 Inches core Or customized core
200pcs/Roll White box packaging
Materials and methods
One of the main goals of a recent study6 was to compare types of holographic
techniques used for anti- counterfeiting methods. A relatively complex hologram
was originated that consisted of a true-color hologram, a real 3D model, 2D/3D
depths, sinusoidal grating dynamic effects, and matte white structures. Accurate
combinations of these structural effects in a complex design were chosen for the
study, to deliver a strong fundament for a comparison of technologies. Multiple
companies that originated holographics were contacted and asked to generate
similar-looking holograms, either by receiving the graphic production data or
without any graphic data, to represent a counterfeit. Four were created
Photographs of the four nickel molds with holographic structures. Multiple
light sources were used for clarity of effects. Analogue origination (a),
e-beam origination (b), dot matrix origination (c), and counterfeit (d).
Courtesy of 3D AG
These four holograms manufactured by four parties set the basis for the empirical
evaluation. The described holograms were presented together with a questionnaire
to about 100 randomly chosen customers who were asked to observe them.
Results and discussion
Based on the results of the questionnaire, three main questions were evaluated and
hypotheses offered.
Are holograms generally trusted?
Customers surveyed were generally not influenced by fear of counterfeits, because
53% of those surveyed had never searched for a security feature on a product. When
asked what features they knew of, 25% didn’t know a single anti-counterfeiting
approach. From the 75% that could name an approach, 51% named only one, 35% named
two, and only 14% named more than three. Among the 19 approaches named, holograms
were the most well known (mentioned by 37 of the total surveyed), followed by
visual and haptic control (16), watermark (15), serial number (11), chip (7),
tamper-evident seal (6), and label and source of origin (4). Given the fact that
25% of all surveyed didn’t know how holograms are made, there seems to be a
mysteriousness about holograms. When questioning the associations people made with
holograms, 55% conveyed security, 36% said quality, and 29% mentioned consumer
protection; 18% had no association, 4% expressed uncertainty, and 10% thought
about compliance. Even though only 55% of the surveyed had never suspected a
hologram could be fake —according to a statistical distribution of points to the
dimensions of trust and distrust — the results convey that holograms are generally
trusted for security.
Can an uneducated consumer identify the relevant characteristics and effects to detect a counterfeit hologram?
When comparing the classical hologram to the counterfeit dot matrix version,
97% of those surveyed detected the dot matrix as the counterfeit (Figure 3).
The manufacturer clearly did not have the original files for production, and
the reproduction was visible by its low resolution and the quality of the
pixels and imagery. Although most consumers do not have the ability to compare
holograms at point of sale, it is believed that an uneducated consumer could
identify sufficient characteristics to detect a counterfeit.
The vast majority of people surveyed recognized the counterfeit hologram
without prior education. Courtesy of 3D AG.
Can an educated consumer identify the real hologram by authenticating overt holography effects?
The survey participants were educated to look for specific features. The features
were explained and then the four holograms were shown. Participants were asked to
find the hologram with the real object recording (the object was shown), and a
special 3D effect was explained as “movement of the round graphical elements in
the plane.” This minimal education in the form of a precise description of effects
resulted in a playful movement of the holograms during inspection by the surveyed:
86% inspected the special 3D effect, while 84% inspected the real object
recording. It could therefore be determined that a consumer could be educated to
identify effects and the real hologram, especially effects originated by analog
classical holography
Rates of identification of specific effects for authentication, with prior
education. Courtesy of 3D AG
This comparison of the original, similar holograms with a counterfeit hologram
helped prove the hologram’s potential. The survey obtained valuable data on the
perception of holograms, and the findings support that holography is a viable
solution for product and brand protection. The survey participants were
educated to look for specific features. The features were explained and then
the four holograms were shown. Participants were asked to find the hologram
with the real object recording (the object was shown), and a special 3D effect
was explained as “movement of the round graphical elements in the plane.” This
minimal education in the form of a precise description of effects resulted in a
playful movement of the holograms during inspection by the surveyed: 86%
inspected the special 3D effect, while 84% inspected the real object recording.
The survey participants were educated to look for specific features. The features
were explained and then the four holograms were shown. Participants were asked to
find the hologram with the real object recording (the object was shown), and a
special 3D effect was explained as “movement of the round graphical elements in
the plane.” This minimal education in the form of a precise description of effects
resulted in a playful movement of the holograms during inspection by the surveyed:
86% inspected the special 3D effect, while 84% inspected the real object
recording. It could therefore be determined that a consumer could be educated to
identify effects and the real hologram, especially effects originated by analog
classical holography