Infra-Red (IR) printing is a printing technology which uses a special toner which is only visible under infra-red light. Infra-red light has a longer wavelength than visible light and thus, it is invisible to the naked human eye.
The [IR Printer] which uses the [IR Toner] with can of course be used on white paper but, the technology can be used to IR print on top of photographs and illustrations. Text and graphics printed using the IR toner can only be read using a dedicated [IR Reader]. This makes the technology more secure than UV invisible ink which can be read by shining UV light. Due to its high security, IR printing is used for authenticating banknotes and certificates issued by government agencies.