The paper and ink used in the production of U.S. paper currency is as distinct as its design. The paper, with the exception of $100 paper, comes to the BEP in brown paper-wrapped loads of 20,000 sheets (two pallets of 10,000 sheets). $100 paper comes to the BEP in loads of 16,000 sheets (two pallets of 8,000). Each of these sheets is tracked and accounted for as it passes through the production process.
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 percent cotton and 25 percent linen. This is what gives United States currency its distinct look and feel. For denominations of $5 and above, the security thread, and portrait or numberal watermarks are already built into the paper when it is received. For the $100 note, a 6mm wide 3-D security ribbon is woven into the paper. Tilt the note back and forth while focusing on the blue ribbon. You will see the bells change to 100s as they move. When you tilt the note back and forth, the bells and 100s move side to side. When you tilt it side to side, they move up and down. This adds a highly advanced level of security to the note.
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.