Intaglio Printing
The Bureau prints currency on high-speed, sheet-fed rotary presses which are capable of printing over 8,000 sheets per hour. Printing plates are covered with ink and then the surface of each plate is wiped clean which allows the ink to remain in the design and letter grooves of the plates. Each sheet is then forced, under extremely heavy pressure (estimated at 20 tons), into the finely recessed lines of the printing plate to pick up the ink. The printing impression is three dimensional in effect and requires the combined handiwork of highly skilled artists, steel engravers, and plate printers. The surface of the note feels slightly raised, while the reverse side feels slightly indented. This process is called intaglio printing.