Let's begin by pointing out that this article is not a tutorial. Enterprising criminals are recommended to look elsewhere.
Counterfeiting costs the U.S. economy millions of dollars annually. According to the U.S. Secret Service, $75 million in counterfeit bills were seized by the Peruvian National Police between 2009 and 2017, yet a counterfeiter reported that most counterfeit currency enters the U.S. via Mexico. Many of the removed bills were crude inkjet copies.
The days of being able to print counterfeit bills on your home computer are not completely dead, but with new security measures, it is increasingly likely that you will be caught. Similarly, it is difficult for large-scale counterfeiters to reproduce the revised $100 bill, which is by far the most counterfeited U.S. denomination because it is in the sweet spot, with the highest value in wide circulation.
The other reason why the $100 is a popular target is that a high-quality counterfeit that can pass a cursory test costs approximately $50 per bill to manufacture.Any criminal attempting to counterfeit high quality $20 bills has a major problem with his business model.
Sophisticated counterfeiting operations still exist, despite new security measures. There are several printing and optical tricks incorporated to make the new bills difficult to reproduce, including features that change with the viewing angle. Color-shifting ink changes the color of the 100 with the angle, and the bell patterns appear, disappear, or change into other features. A blue 3D security ribbon is woven throughout the paper in the center of the bill, and microlenses within the ribbon produce the changing features. Finally, raised printing produces even more texture to the bill's surface.
These steps cost the government 60% more to produce the bill (up to 12.5 cents per bill) but are likely to more than pay the extra cost back in decreased counterfeiting attempts. Anyone who manages to duplicate the inks and 3D ribbon would have to invest so much in equipment and raw materials that they would have to pass off an incredible number of $100 bills to recoup their "investment."
How can you spot a counterfeit $100, or crude fakes of lower denominations? The Secret Service offers a few tips.
- Portraits – Properly printed bills have distinct features in the portraits. Fakes often have flat and lifeless details.
- Seals – The Treasury and Federal Reserve seals are crisp and distinct on real bills, but fakes can have blunt or uneven points on the outer saw-tooth pattern.
- Borders –?Blurred borders or imprecise centering is a big tipoff of a counterfeit.
- Serial Numbers – A proper serial number is printed in the same ink color as the seals and has a distinct font style with even spacing. Obviously, if you find two bills with the same serial number, at least one is fake, and sequential numbers should at least get your attention to look a bit closer at the bills.
- Paper – There are tiny blue and red fibers embedded in real currency. Counterfeits attempt to duplicate the effect by surface printing. Close inspection will show the difference.
- Starch – Did you ever wonder why clerks use special yellow pens to test higher-denomination bills? They are testing for starch in the paper. Real bills use special starch-free paper. The yellow pens have an iodine base that turns a bluish-black color upon contact with starch.
- Texture –Real bills have raised printing that produces texture. Test a bill against standard copier paper to get a feel for the difference.
- Watermark – A faint watermark image of the portrait will appear when real bills are held up to the light. If the portrait doesn't match, somebody has bleached an old bill of lower denomination and reprinted it to increase its value.
The Treasury has made it harder on counterfeiters, but people must still be aware of the potential for fakes, even crude ones. Most bills don't get much scrutiny during cash transactions, so be on the lookout for anything unusual—at least until mobile pay systems take over the world and those funny green rectangles become museum artifacts.