Currency:
The paper and ink used in the production of U.S. paper currency is as distinct as its design. The paper comes to the BEP in brown paper-wrapped loads of 20,000 sheets (2 pallets of 10,000 sheets). Each of these sheets is tracked by the BEP as it passes through the production process. And, the total inventory of 20,000 sheets is continually reconciled to make sure each sheet is accounted for. Currency paper is specifically made for the BEP by Crane Paper Company. The ordinary paper that consumers use throughout their everyday life such as newspapers, books, cereal boxes, etc, is primarily made of wood pulp; however, United States currency paper is composed of 75% cotton and 25% linen. This is what gives United States currency its distinct look and feel. For denominations of $5 and above, the security thread, and watermark are already built into the paper when it is received.
All bills, regardless of denomination, utilize green ink on the backs. Faces, on the other hand, use 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 the BEP. Inks headed for BEP presses also undergo continual quality testing.