More commonly known by its acronym NCR, this is paper which, when applied with pressure by a pen or typewriter, causes a chemical reaction between different coatings on the back of the page written on and the front of the paper below, reproducing a blue or black tinted "carbon copy" on the following pages. It works in a similar manner to carbon paper, but eliminates the need for the extra sheet between, making NCR useful for cash machines.
In fact, NCR paper was developed by the National Cash Register Company in 1954 but brought into full use in 1983. Everytime you sign a debit or credit card receipt and get a yellow slip that gets lost in your pocket somewhere, you are using NCR paper.