Black Light and CounterfeitsBy

Black Light and Counterfeits - Examining The $100 Bill

The $100 bill (technically a $100 Federal Reserve note) issued in the mid-1990s was quite different from the earlier series of $100s in U.S. currency. The most obvious difference is the size and off-center location of Franklin's portrait. It is left of center and Franklin's head alone takes up the space formerly occupied by a head and shoulders view. But these changes are relatively minor compared to the "high-tech" features hidden inside the paper fibers and invisible to the unaided eye in ordinary light.

You're already familiar with the embedded security thread in U.S. currency of five dollars and higher. When held to the light, the thread appears to the left of the portrait and has the denomination spelled out separated by the letters "USA". The security thread in the newer $100s still has those features but also another important one--the thread fluoresces red under long wave black light (Fig. 3). This thread is the only feature of authentic U.S. currency which fluoresces under black light. If any other part of a new $100 fluoresces, it is counterfeit.

Many counterfeits, on the other hand, do fluoresce when exposed to black light. This is caused by chemicals and dyes in the paper used in laser printers and color photocopiers favored by amateur counterfeiters. Another cause of fluorescence is bleaches used to "wash out" ink on genuine currency. With the ink of a low denomination bleached out, counterfeiters will print a higher denomination on the genuine paper stock.

Another hidden feature of new $100s is a watermark of Franklin's head which appears only when held to a strong light (Fig. 4). Immediately under the watermark is another security feature. The number "100" in the lower right hand corner of the front side appears green when viewed straight on; the color changes to black when viewed at an angle (Fig. 5).

The $100 note was the first piece of currency to receive these new features. All earlier $100 notes are still legal and there is no plan to recall them.

For more information, contact your local bank, a Federal Reserve Bank or U.S. Secret Service office.


Fig. 1 Front and back of 1990 series $100 bill.


Fig. 2 Front and back of new $100 bill


Fig. 3 Security thread fluoresces reddish orange in black light.


Fig. 4 Watermark of Franklin's portrait appears only when held to a strong light. The image appears on the right side of the front.


Fig. 5 The "100" in the lower right hand corner appears green when viewed directly; it appears black when viewed at an angle.