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January 9, 2018

The Science of Security Ink

From lottery tickets to pharmaceutical bottles, security ink keeps customers and businesses safe. As inkjet technology evolves, so too does the range of applications for security inks.

Security ink doesn’t have to be invisible

One common misconception about security inks is that they are the same as invisible inks. While many security applications of ink do take advantage of invisible ink, there are a variety of visible security ink solutions as well.

Close up of American Passport with security ink that changes from green to goldFor example, many passports contain photosensitive ink that is visible to the naked eye, but changes color or disappears when placed under a UV light. On the U.S. passport, the letters “USA” are printed with a security ink that appears gold when viewed from one direction, and green when viewed from another.

On the other hand, many people assume security ink is only for protecting important documents like passports and paper currency, but that isn’t the case. There are a number of everyday applications where security ink is a common protective measure, including:

  • Concert and sports tickets
  • Coupons
  • High-dollar branded products like watches and purses
  • Prescription medicine bottles
  • Lottery tickets

With such wide-ranging applications, security ink doesn’t just protect countries from master forgers. It protects consumers from fraud, deception, and (in the case of pharmaceuticals) physical harm.

What makes invisible ink, invisible?

Ink, by definition, does not have to have color. In fact, while dyes and pigments are what give ink its physical color in most applications, in security applications, the same dyes and pigments can be formulated to be naked to the visible eye. Additionally, taggants – particles added to ink that are developed to react in proximity of a unique “reader” or verifier – are typically microscopic in size.

Because invisible ink, by design, does not have color, most applications of invisible security ink involve a taggant that reacts with a specially designed camera, light, or scanner. When implementing security ink, the taggant is developed to react only with proper equipment using a UV, infrared, or near-infrared light at a specific wavelength. While heat- and chemical-activating inks do exist, they are more popular in kids’ science experiments than in enterprise applications.

Closeup image of UV ink on a Canadian passport

Source: Wilson Hui

Just how specific is the scanner used? It depends on the level of security needed. In less secure applications, the ink reacts under a broad range of wavelengths. For example, ink on a concert ticket might fluoresce under any black light. In some high-security cases, the taggant reacts only under a light specifically calibrated for that ink.

In short, the components in an invisible ink are all developed and mixed to create a fluid that is transparent to the naked eye, but reactive (and visible) under certain operating conditions.

Creating security ink

To create a security ink for a custom application, ink manufacturers must consider a variety of elements:

  • Substrate – What material will the ink be printed on? How can we ensure the ink adheres properly to the substrate?
  • Operating conditions – Will the printed item be used once or many times?
  • Visible properties – Does the ink need to be invisible to the naked eye?
  • Detection mechanism – Is there specific equipment that will be used to validate authenticity (as in light-sensitive ink on a passport) or will it be validated by the naked eye (as in the watermark on a U.S. $20 bill)?
  • Security level – Are there other security protocols being implemented for the application? Just how secure does this item need to be?
  • Printing – What production speed needs to be maintained? What printing equipment or technology will be used?

These, and many other questions, lead ink manufacturers to develop an ink formulation that meets all of a customer’s needs.

Of course, the ink manufacturer isn’t the only participant in these discussions. Companies looking for security solutions often have to work with a printer as well as the security company that provides the taggant and the machine people will use to confirm the authenticity of the ink.

Security printing in the age of inkjet

Security inks have been around for a long time, but technological advances made possible through inkjet technology innovation have greatly expanded the availability and capability of security inks.

Close up of U.S. Dollar Bill

Inkjet printing can allow customization on the individual level

Because inkjet printing requires minimal setup time, printed security ink can be customized at a per-unit level. For example, individual SKU markings on pharmaceutical bottles can help identify theft and counterfeiting at all stages.

For businesses, inkjet security ink has obvious value, reducing printing downtime and expanding production line capabilities. But consumers also benefit! Greater adoption of security measures by companies ultimately protects customers from harm.

 

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