Engraving
Production of United States paper currency is not an easy or simple task, but one that involves over 65 separate and distinct steps in the production process. Money begins with the hand-engraved piece of soft steel, known as a master-die. Separate portions of the design, such as the portrait, the vignette, the ornamentation, and the lettering are hand-cut by the engravers. If you look closely at a currency note, you will notice that the portrait consists of numerous fine lines, dots and dashes which vary in size and shape. The magnificent artistry and skill of the engraver bring the portrait to life. The process of engraving is the first step in a unique printing technique known as intaglio printing.

Siderography

In simplest terms, siderography is the means by which multiple images of the hand-engraved die are transferred to a printing plate. The original dies are stored and transferred to a printing plate. The original dies are stored and if necessary may be used again and again. For example, the Lincoln portrait on the five dollar note was originally engraved in 1869, but can still be used today in the production of a five dollar note.

Plate Making

The master die is subjected to tremendous pressure, heated and an impression of the die is taken. An alto and/or relief (a raised image of the die) is cast in plastic. Multiple plastic images of the various components (such as the decorative scrollwork) of the note are made, fitted and welded into the necessary plate configuration consisting of thirty-two notes. Plastic altos are placed in an electrolytic tank and are used to produce a series of plates, which are then cleaned, polished, and carefully inspected by an engraver. If the plates pass the scrutiny of the engraver, the final chromium coated basso (recessed image) plate is made and another multiple subject intaglio plate is ready to place on the printing press.

Printing

The Bureau prints currency on high-speed, sheet-fed rotary presses, which are capable of printing over 8,000 sheets per hour. Each sheet is forced, under extremely heavy pressure (estimated at 20 tons), into the finely recessed lines of the plate to pick up the ink. The printing impression is three dimensional in effect and requires the combined handiwork of highly skilled artists, bank note engravers, and plate printers. The surface of the note feels slightly raised, while the reverse side feels slightly indented. The backs of the notes are printed with green ink, allowed to dry for 24 to 48 hours. The faces are then printed with black ink and also allowed to dry.

Examining

Each stack of 32-subject sheets is cut in half and each side is examined for defects. If the sheet meets the examiner's inspection standards, it is then ready for numbering and processing on the Bureau's overprinting and processing equipment.

Overprinting

A letterpress overprints with black ink the Federal Reserve District seal and its corresponding number designation. It then overprints the Treasury seal and serial numbers in green ink. Two guillotine cutters slice the notes into two note units (100 sheets at a time) and finally into single stacks of one-hundred notes. The units of 100 notes are banded and packaged into "bricks" containing 40 units; each "brick" contains 4,000 notes. The bricks are distributed to one of the twelve Federal Reserve Districts, which issue the notes to local banks. If a finished note is found to be imperfect after it has been overprinted, it is replaced with a "star note". In design, star notes are exactly like the notes they replace, but they can carry an independent series of serial numbers. The star appears after the serial number in place of the suffix letter on Federal Reserve notes. The serial number of the imperfect note is not used again in the same number sequence.

Portraits and Designs on U.S. Currency

The design features on our currency have historical and idealistic significance, but may not include the likeness of a living person, and do not have sectarian significance. The design of paper currency, as well as the material used in its production, is determined by the Secretary of the Treasury.