Currency production is not an easy or simple task, but one that involves precision, highly trained and skilled craftspeople, specialized equipment and a combination of traditional, old world printing techniques merged with sophisticated, cutting edge technology.
Since 1862, BEP been entrusted with the mission of manufacturing the nation’s currency. All U.S. currency is printed at our facility in Washington, D.C. and at our facility in Fort Worth, Texas. In addition to manufacturing U.S. paper currency, BEP also prints a variety of U.S. government security documents.
Designing and Engraving
The design starts with ideas and rough sketches from our banknote designers, who develop the overall look, layout and artistic details. They work closely with engravers, who use a combination of traditional and modern techniques to engrave the portrait on the front, the vignette on the back, the ornamentation, and the lettering. Each engraving consists of numerous detailed fine lines, dots and dashes that vary in size and shape.
The magnificent artistry and skill of the engraver brings the portrait to life with an array of traditional tools and cutting-edge digital technology.
The intricate carvings and etchings that we see every day on our paper currency are engraved into a network of fine lines and grooves into steel dies that are transferred and processed to create working printing plates. After careful inspection and minor repair if needed, these plates are cleaned and polished. The working plate is chrome-plated for hardness and is then ready to go on the printing press.
Ink and Paper
All notes, regardless of denomination, use green ink on the backs. Faces, on the other hand, use a combination of black ink, color-shifting ink in the lower right-hand corner for the $10 denominations and higher, and metallic ink for the freedom icons on redesigned $10, $20 and $50 bills. The $100 note's "bell in the inkwell" freedom icon uses color-shifting ink. These and the other inks appearing on U.S. currency are specially formulated and blended by BEP. Inks headed for BEP presses undergo continual quality testing.
A fancy word for paper in the currency business is substrate. U.S. currency paper is composed of 25% linen and 75% cotton, with red and blue fibers distributed randomly throughout to make imitation more difficult. The paper is made specifically for the Bureau of Engraving and Printing by Crane Currency in Dalton, Massachusetts and it is illegal for anyone other than BEP to possess this paper. Paper for the $5 bill and above is made with specific watermarks and security threads. While the percentage of counterfeit notes in circulation remains small, there are ever evolving new techniques that we need to stay ahead of.
Currency printing is built on the principal of layering each printing process on the substrate. Each print technology has a unique fingerprint on how the ink transfers from the plate, the inks they use and how it lays on the substrate, thereby building security into the currency with every production step.
The first step is adding color through offset printing. To accomplish this, BEP has three offset printing presses in D.C., and four in our Texas facility. On this press, the face and back of the sheet is printed at the same time. All denominations, excluding the $1 and $2 notes, are printed in offset first, where detailed background images using unique colors are blended together as they are added to “blank” currency sheets.
The background colors are then printed by state-of-the-art, high speed, sheet-fed, presses. These massive machines are more than 50 feet long and weigh more than 70 tons capable of reaching speeds of 10,000 sheets per hour. In addition to online computer inspection, press operators will pull a sheet after every 500 impressions (approximately), and carefully examine it to ensure that the colors and alignment (which we call “registration”) remain consistent to our rigorous quality standards.
Intaglio – (also called Plate Printing or Steel Plate Printing)
Intaglio is the next layer of the printing process for the denominations that went through offset, and the first stage of printing for the $1 and the $2 notes. Here, ink is applied to the engraved plate. The excess ink is removed from the non-image area of the plate, thereby leaving ink only in the engraved recessed areas. Paper is then laid on top of the plate, and the two are pressed together under great pressure. As a result, the ink from the recessed areas is pulled onto the paper, creating a slightly raised finished image. When dried, the tactility feels like fine sandpaper. Intaglio printing is very specialized and used on high value negotiable documents like currency and portions of passports. Intaglio is used for the portraits, vignettes, scrollwork, numerals and lettering that is unique to each denomination.
BEP’s intaglio presses have the latest technology to ensure the highest of quality and security of U.S. currency. The presses each weigh 57 tons and print with up to 20 tons of pressure. They can produce at speeds of 10,000 sheets per hour and can produce 32 or 50 notes per sheet.
The intaglio presses first print the back of the currency sheets in green ink. The sheets are then taken to a vault to dry for three days. A common work-in-process vault might contain $50 to $100 million of notes at any one time, depending on the denomination being printed. After the ink on the paper is dry, the faces of the notes are printed with black ink. The notes will dry again for another three days before going on to the next phase of production. At any given moment within the Washington, D.C. facility, for instance, there may be up to $300 million dollars in various phases of production.
Offline Currency Inspection System (OCIS)
To ensure only the highest quality sheets move to the numbering operation, sheets are thoroughly examined using OCIS, a state-of-the-art computer system integrated with cameras and sophisticated custom-built software to divide each note into 125,000 pixels or 4,000,000 pixels for the entire sheet at a speed of 2½ sheets per second. OCIS completely analyzes loads for quantity and quality of untrimmed printed sheets inspecting both sides of the currency sheets. Good sheets proceed forward for
numbering while rejected sheets are numbers and processed through a single note processing machine.
Single Note Inspection (SNI) inspects and sorts finished numbered notes from the defective OCIS sheets, reclaiming good notes from destruction. These fit notes are either recovered from the finished product on quality-hold, or reclaimed from the standard production waste streams.
The third and final printed layer of U.S. currency is letterpress printing. During this process, the press feeds two 16-subject sheets of currency and prints two green serial numbers, the black universal Federal Reserve seal, the green Department of the Treasury seal, and the corresponding Federal Reserve identification numbers. BEP currency uses two types of letterpress equipment.
Currency Overprinting Processing Equipment and Packaging (COPE/PAK)
At BEP we love acronyms. COPE/PAK combines a rotary letterpress and an automated finishing and packaging line. COPE presses have been specially designed for BEP to print and process 32-subject sheets of currency. 100-sheet stacks pass through two sharp guillotine cutters. The first cut is made horizontally, leaving the notes in pairs. The second cut is made vertically, and for the first time you see individual notes, 100 to a pile. These are bound with denomination bands.
In the COPE/PAK section, there is a machine called “1,000 note bander.” The rotating carousel collects 10 packages of notes and bands them together, resulting in a stack of 1,000 notes (one bundle). These notes are then shrink wrapped and a bar code is affixed, which contains the notes’ serial numbers and Federal Reserve Bank information.
The next rotating carousel shrink wraps four of these bundles into a final currency brick containing 4,000 notes. As a final stage, the four bricks are collated together and shrink wrapped into a 16,000 note Cash Pak. From there, they are placed into the vault to await pick-up by the Federal Reserve. One brick of $100 bills would contain $400,000; one skid of those bricks would contain $64 million.
Large Examining Printing Equipment (LEPE)
LEPE represents the newest generation in numbering and processing equipment for BEP. In February 2014, BEP ushered in a new era by printing currency on 50-subject sheets versus 32 notes per sheet. Sitting at 144 feet long, these mammoth machines are state-of-the-art, specifically designed for BEP, combining multiple currency production processes at once: full sheet examination, letterpress printing functions, product verification, and cutting and packaging currency. Currently, only $1 and $5 notes are produced in 50-subject sheet format. The $20 note is next in line for transition into the larger format and is scheduled to be in production by summer 2022.