Thermal paper

Most receipts are printed on thermal paper - no ink used, the paper is heated where the type is set to produce darkening, it is now possible to produce 2 colours by heating paper to two different temperatures. Degrades in heat and light, even if kept in optimum conditions will only last 3- 5 years.

As time increases - Info contained decreases.

The more the receipt is handled, the more the paper is heated therefore darkens and information fades into black.