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.
