Paper money features green, black, metallic and color-shifting ink that's formulated and blended specifically for banknotes by the U.S Department of the Treasury Bureau of Engraving and Printing.
The cotton and linen paper mix makes the banknotes much more durable than normal paper. The Bureau of Engraving and Printing estimates that it takes roughly 4,000 double folds before a banknote tears. How long a bill lasts in circulation depends on how often it is used by the public. For instance, $10 bills last an average of 4.2 years, while $100 bills typically last for 15 years.
As of 2014, the Crane Paper Company supplies the BEP with currency paper in wrapped packages of 20,000 sheets. The BEP tracks every sheet as it goes through production. The BEP receives the paper sheets with the watermarks and security marks already embedded within it. Offset printing and intaglio printing are used to impress the images onto the banknotes.
According to federal law, the Secretary of the Treasury chooses the portraits and designs that appear on banknotes. The portraits on current banknotes, as of 2014 have been in use since 1929.Learn more about Currency & Conversions