Banknote Security Features – Public Features

Posted by Chalermkiat Lett on

Have you ever wondered about banknote security features? Security features are vital to the prevention of counterfeiting. Companies in the banknote industry including hologram companies, ink companies, governments and currency printers are constantly innovating new and improved methods of keeping counterfeiters from replicating read notes. New security features are released each year which are harder to replicate and easier to check, making it more difficult for fake money printers to disrupt the integrity of a country’s economy.

Security features include many public features and a number of secret features only know to experts and government officials with a need to know.  Public features are used to enable the public to intuitively recognize a banknote as real and its denomination.  The US$100 which was designed before 2010 and issued in 2013 has several very difficult to replicate public features.

US currency is made of long fiber cotton fiber. This gives is a unique feel relative to most paper.  US money feels more like fabric than paper. The special feel is a public security feature.  Even blind-folded, most people can tell feel the difference between a US banknote and a piece of printed paper.  The raised ink, created by intaglio printing- an embossing technique, adds to the uniqueness of the feel.  The intaglio ink is pressed into the paper and stands proud off the paper between 20 and 80 microns high.  Intaglio is usually used for portraits and borders to create that feel.

USA 100 dollar bill from 2006
USA 100 Dollars | 2006 | P-529
Source: Banknote World

Intaglio printing is also critical to one of the most important banknote security feature – the portrait.  A good public security feature needs to be recognized as genuine by the public with little to no training or equipment, and in all kinds of lighting.  Humans innately recognize faces and can differentiate even the smallest changes.  We all experience this when we see a coworker or friend who gets a haircut or uses different make-up.  We might not immediate recognize the change, but we do notice that there is something that is different.  This is one of the reasons that portraits are used on banknotes.  And in the portraits there is special attention to the details of the eyes, nose and mouth. These are the areas we focus on most when we look at others.  Look at the wrinkles and eyebrows around Ben Franklin’s eyes.  The detail is very important. 

The US $100 also uses two public security features that have become industry standards.  The Liberty Bell in an Ink Well is printed with color shifting ink.  When the banknote is tilted, the colors of the ink changes and the bell pops.  This feature is easy to recognize and extremely difficult to replicate.  The $100 was the first US banknote to use the blue plastic stripe. This is called an embedded thread and comes from Crane Currency.  The thread is added during paper production making it harder to replicate.  The feature itself is unique and interesting because when you tilt the banknote; like you did to see the color shifting ink, the images in the blue stripe move perpendicular to the way you move it.  The images – a bell and a ‘100’ also seem to disappear into the paper.  Your brain would expect the images to move in the same direction you move it.  Since it moves in a different direction, your brain senses the unusual movement and pays more attention to it.  This effect makes the feature very obvious and effective.

USA 100 dollar bill from 2013
USA 100 Dollars | 2013 | P-543
Source: Banknote World

US currency uses other public features such as the big $100 on the reverse.  This is not so much for counterfeit resistance but more to help poor-sighted individuals better recognize the denomination. 

There are many other banknote security features developed in the last 10 years or did not fit the US needs at the time.  Many banknotes are now produced using a plastic substrate instead of paper.  Clear polymer banknotes can have some features such as clear areas (called windows) that paper does not have.  Many banknotes including the new Canada series also use large holographic features for the public.  Maybe most interesting is that suppliers have advanced their features to be even harder to replicate but easier to identify.  Color shifting inks have been upgraded to include motion in addition to color changes.  Crane Currency has added new optical effects to their embedded thread and made the moving images even clearer to see. 

Counterfeiters never rest.  Neither do the banknote designers and suppliers in the industry.  Lets hope that these feature developers will always stay one step ahead of the criminals.


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