The newest $20 bills printed by the Treasury contain three special security features that are impossible to fake with an inkjet printer:
- Embedded in the paper, a plastic security strip runs vertically up one side of the note. If President Andrew Jackson is facing you, then the plastic strip is on the left side. Upon close inspection of this security strip, you can see the words "USA TWENTY" and a small flag repeated along the thread. This should be visible on both sides of the bill.
- Located in the bottom right corner on the face of the bill, the number "20" is made of color-shifting ink. A slight backward and forward shift of the bill changes the number "20" from copper to green.
- A faint and smaller version of Jackson's portrait (as seen on the face of the bill) is "hidden" within the paper itself. If you hold the bill up to a light, this watermark is immediately evident from either side of the bill.
How did Nelson get around these features? The article states it this way:
In other words, Nelson took pre-1996 bills and used them as the models for his reproductions. Most people will still accept the older bills, and since these older bills have none of the fancy features of the newer ones, they are much easier to reproduce.
By putting all of these tricks together, Nelson was able to create fake money that fooled most of the people most of the time -- $800,000 is a lot of money.
So, how did he get caught?