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Chloe Effron

Security Features in U.S. Paper Currency

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Chloe Effron

It’s not enough for money to simply serve its basic function as legal tender, it’s also got to be smart—and increasingly so. Each time bills are redesigned they gain security features that make them more and more difficult to reproduce, and while U.S. paper currency has its fair share of detractors, there are some pretty awesome design elements at work when it comes to what’s in our wallets.

THE PAPER

Paper money isn’t actually paper at all—at 75 percent cotton and 25 percent linen, it’s essentially fabric, making it much more durable than actual paper would be. It takes about 4000 double folds before a bill will tear.

Graphic by Chloe Effron

A single company has provided the paper for U.S. bills since 1879—Crane & Co. in Dalton, Mass. The company has a storied place in U.S. history. In 1776, it was called Liberty Paper Mill, and serviced Paul Revere when he needed to print notes for paying American Revolution soldiers. 

Finally, "greenbacks" they may be, but embedded throughout Federal Reserve Notes are tiny red and blue fibers. Counterfeiters often try to simulate these by printing tiny red and blue lines on the paper.

HIDDEN FEATURES

In a $5, $10, $20, or $50 bill, the paper contains a security thread and a watermark. To see them, you have to hold the note to the light, and the placement and style are different for each bill. The security thread glows a specific color when exposed to ultraviolet light.

Graphic by Chloe Effron

The $100 bill also has a wider, 3D holographic blue security ribbon woven into the paper to the right of Franklin’s portrait. If you tilt the note back and forth you can see the bells change to 100s, and move side to side. This feature adds a highly advanced level of security that’s difficult to simulate.


PRINTING

The redesigned $10, $20, $50, and $100 bills go through several stages of printing in order to create the finished notes. Each bill is printed four times on three different kinds of printing machinery. All bills utilize green ink on the backs, but faces use black, color-shifting, metallic ink, and other inks which are specially formulated and blended by the Bureau of Engraving and Printing.

In 2003, with the introduction of the redesigned $20s, subtle background colors were added to the currency to enhance the security. For these denominations, offset printing is the first printing that occurs on the “blank” paper. They’re printed using the BEP's Simultan presses, which are over 50 feet long and weigh over 70 tons. They're capable of printing 10,000 sheets per hour, and operators will regularly examine sheets to make sure the colors are remaining constant.

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Weird
Switzerland Flushes $1.8 Million in Gold Down the Sewer Every Year
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Switzerland has some pretty valuable sewer systems. As Bloomberg reports, scientists have discovered around $1.8 million worth of gold in the country's wastewater, along with $1.7 million worth of silver.

Scientists at the Swiss Federal Institute of Aquatic Science and Technology examined sewage sludge and effluents, or discharged liquid waste, from 64 water treatment plants and major Swiss rivers. They did this to assess the concentrations of various trace elements, which are "increasingly widely used in the high-tech and medical sectors," the scientists explained in a press statement. "While the ultimate fate of the various elements has been little studied to date, a large proportion is known to enter wastewater."

The study, which was recently published online in the journal Environmental Science & Technology, revealed that around 94 pounds of gold makes its way through Switzerland's sewage system each year, along with 6600 pounds of silver and high concentrations of rare metals like gadolinium and niobium. For the most part, these metals don't harm the environment, researchers say.

With gold and silver quite literally flowing through their sewers, is there any way that Switzerland could turn their wastewater into wealth? Scientists are skeptical: "The recovery of metals from wastewater or sludge is scarcely worthwhile at present, either financially or in terms of the amounts which could be extracted," the release explains.

However, in the southern canton of Ticino, which is home to several gold refineries, the "concentrations of gold in sewage sludge are sufficiently high for recovery to be potentially worthwhile," they conclude.

Switzerland is famous for its chocolate, watches, and mountains, but it's also home to major gold refineries. On average, around 70 percent of the world's gold passes through Switzerland every year—and judging from the looks of it, much of it goes down the drain. As for the sewer silver, it's a byproduct of the chemical and pharmaceutical industry, which is a cornerstone of Switzerland's economy.

[h/t Bloomberg]

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Lists
14 Things You Owned in the '70s That are Worth a Fortune Now
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From old toys and housewares to books and records, these pieces of '70s memorabilia have aged (and increased in value) like fine wine.

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