(Above) Counterfeiting was rampant in the colonies, and the punishment was death. Printers who were authorized to print money designed as many things as possible to frustrate the counterfeiter. It was quite common for mica chips and/or blue threads to be put into the paper as additional security devices.
(Above) Front and back of a 1775 Pennsylvania 50 Shilling note. Check out the complicated engraving and overprinting.
(Above) This entire line of Pennsylvania currency was recalled due to counterfeiting. In this case, a large “X” was drawn on the face of the note when it was redeemed. Here you see the front and back of the note.
(Above) I’m including these North Carolina notes because I am digging the typography—especially the calligraphic swooshes of the words “North Carolina” in the top piece. Occasionally, printers would intentionally misspell—or slightly change the spelling of the state—from the front to the back of the note—just to mess with the heads of counterfeiters.