How Does a Pen to See if Money Is Real Work?

Counterfeit money poses a challenge in daily transactions. Counterfeit detection pens offer a quick, accessible method for a preliminary check of bills. These tools help identify fraudulent currency and mitigate financial losses.

Understanding Counterfeit Detection Pens

Counterfeit detection pens operate on a straightforward chemical principle involving iodine. The pen’s ink contains an iodine solution that reacts with components in paper. When applied to a bill, the iodine interacts with starch, a common paper additive. Genuine United States currency is printed on a unique blend of cotton and linen fibers that does not contain starch. This unique paper composition is a security feature.

Interpreting Pen Results

The pen’s ink reacts with paper, producing color changes that indicate a bill’s authenticity. If the mark remains clear, amber, or light yellow, it suggests the absence of starch. This indicates the currency is genuine. Conversely, if the mark turns dark brown or black, it signifies the presence of starch. A dark reaction suggests the bill is counterfeit.

When Pens Are Not Enough

While counterfeit detection pens provide a rapid initial assessment, they have limitations. These pens only detect starch in paper. Sophisticated counterfeiters may bypass this method by bleaching lower-denomination genuine bills and reprinting them with higher denominations. Since the original paper is authentic, it lacks starch, the pen indicates it as genuine.

Counterfeiters also use specialized papers that do not contain starch, rendering the pen ineffective. The pen serves as a preliminary screening tool, not a definitive verification method.

Advanced Counterfeit Identification Techniques

Verifying the authenticity of currency requires examining multiple security features embedded in genuine bills.

• Genuine U.S. currency has a distinct texture, often described as crisp and slightly raised, which comes from the intaglio printing process.
• Holding a bill to the light reveals a watermark, a faint image of the portrait visible from both sides of the bill.
• A security thread, a thin, embedded strip with microprinted text, glows a specific color under ultraviolet light.
• Tilting the bill causes color-shifting ink, found on the numbers in the lower right corner of denominations $10 and higher, to change color from copper to green.
• Additionally, genuine bills contain microprinting, tiny, legible text that appears as a solid line to the naked eye but is readable under magnification.

Responding to Suspected Counterfeit Currency

If you suspect you have received a counterfeit bill, it is important to handle it carefully to preserve potential evidence.

• Do not return the bill to the person who passed it to you.
• If possible and safe, try to delay the individual and observe any descriptive details about them.
• Immediately contact your local police department or the United States Secret Service, as counterfeiting is a federal crime.
• Handle the bill as little as possible, placing it in an envelope or plastic bag to avoid smudging fingerprints or disturbing other evidence.
• Never attempt to re-circulate a suspected counterfeit bill, as this is illegal and contributes to the spread of fake currency.