Paper money in the United States has taken on many different styles and forms since it was first created in 1690. Today, some countries print their "paper" money on polymer plastic substrates.
The production of paper money involves four basic components:
- Paper, to print the money on
- Ink, to impart the designs on the paper
- Plates, to put the ink onto the paper
- Printing, the process that brings together the paper, ink, and design plates to print U.S. paper money
The paper that the United States Bureau of Engraving and Printing uses to print money is specially created by Crane and Co., a Massachusetts-based company that has provided the U.S. Bureau of Engraving and Printing with paper for U.S. currency since 1879. And actually, it isn't paper at all. Paper is made from wood fibers that are processed into thin sheets. Federal Reserve notes are a blend of 25 percent linen (fibers from the flax plant) and 75 percent cotton.
Each sheet also contains special anti-counterfeiting measures. If you look closely at any United States dollar bill, you will see a combination of blue and red fibers throughout the paper. These are placed randomly during the production process and make it more difficult for counterfeiters to produce this special paper. Additionally, a mylar ribbon is encased inside each piece of paper. This ribbon will glow under ultraviolet light and has the value of the note printed on it. The new $100 notes have a wider mylar hologram ribbon that weaves in and out of the top surface of the bill.
The ink that is used to print our paper currency in the United States has been specially formulated by the United States Treasury. The secret formula used to produce the ink is also another form of anti-counterfeiting measures used in the production of United States paper currency. The back of each bill usually uses special green ink and is printed first. The front of the bill uses a variety of ink that depends upon the denomination of the bill being produced. This can include black ink, color-shifting ink, and metallic ink.
Engravers at the United States Bureau of Engraving and Printing are the highly skilled artists that engrave a web of fine lines and grooves into a steel plate by hand. They use sharp tools, commonly called gravers and acids, to cut the fine lines, dots, and dashes uniquely inscribed into each plate. A graver is a hand-sized, hardened steel tool shaped to a sharp point. Gravers come in different sizes and shapes; the point can be wide or slim, flat or pointed, depending upon which type of cut the engraver wishes to produce.
The engraver works in a mirror image, so everything on the master plate is backward. Therefore, when it is used to produce paper money, it will be printed correctly. Throughout this whole process, computers are not used in the creation of these plates.
Also, each master plate is created by many different artists. Some engravers specialize in creating portraits; others specialize in creating design elements such as buildings or scenes that are called vignettes, while other engravers specialize in lettering and scrollwork.
This master plate is then used to create a printing plate with thirty-two notes on one plate. This is the plate that will be mounted onto the intaglio printing press used to create the images on the paper's surface.
The actual printing process used by the U.S. Bureau of Engraving and Printing consists of several steps. There are many anti-counterfeiting measures contained on each note produced. This includes colorful backgrounds, color-shifting ink, and the intaglio printing process.
In 2003, the United States began using subtle background colors in an effort to thwart counterfeiters. The twenty-dollar bill was the first bill to be redesigned in many years. Photo engravers receive the master design from the offset plates' designers and load them into a printing press. A thin sheet of steel coated with a light-sensitive polymer is exposed to ultraviolet light to transfer the image to the plate.
These colorful images can be as simple as a geometric design or as complicated as a subtle portrait or calligraphy in the background. Given the complexity and graduated differences in color, this background printing is another step in adding additional security measures to our currency.
The next step involves printing the major design elements on the note. The intaglio process consists of mounting the engraved plates on the printing press. The printing plate is then covered with a thin coat of ink, and a wiper removes the excess ink from the surface of the plate. Only the recessed areas of the plate will contain the ink. The printing press uses 20,000 pounds of pressure per square inch to transfer the design to the paper. This forces the ink that is in the recessed grooves of the printing plate onto the paper.
The goal of the Bureau of Engraving and Printing is to produce flawless and perfect paper money every time. To ensure the quality of this process, the sheets of notes are put through inspection. A human can't inspect each and every note of the millions of notes that are produced. Therefore, they passed through a machine that uses sophisticated software to analyze each sheet. This sophisticated inspection process can inspect 8,000 sheets per hour.
This is the final stage of the printing process. At this point, the thirty-two note sheets have been cut in half and have sixteen notes per sheet. Each note receives a serial number for quality control and tracking, the universal black Federal Reserve seal, the green Department of the Treasury seal, and the corresponding Federal Reserve identification numbers.
Stacking, Cutting, and Packaging
The back of the bill is printed first. It then takes seventy-two hours for the ink to dry and cure on the surface of the paper. After the back of the note is dried, it is fed through the press again to print the front of the note. Once again, they sit for seventy-two hours for the ink to dry and cure.
Finally, the currency sheets that contain sixteen notes (two across and eight down) are gathered into stacks of 100. Each stack passes through a guillotine cutter. The first cut is made horizontally, leaving the notes in pairs. The second cut is made vertically, and we now have individual notes.
The notes are then strapped, bundled, and bricked for distribution to the Federal Reserve Bank.
|Package Type||Total Number of Bills|
|100 notes = one strap||100 notes|
|10 straps = one bundle||1,000 notes|
|4 bundles = one brick||4,000 notes|