Abstract: A self-service deposit terminal (10) is arranged to authenticate bank notes by exposing them to ultra-violet (UV) light which causes forged notes comprising wood-based paper to fluoresce. Each note (36) is individually transported between a UV light tube (38) and a first photo-diode (40). The level of light emitted by the UV light tube is monitored by a second photo-diode (52). The amplified output of this second photo-diode acts as a threshold value. The amplified outputs of both photo-diodes are applied to a Schmitt trigger (60) which outputs a high signal if the tested note is judged to fluoresce and a low signal if it does not. The output of the Schmitt trigger (60) is applied to a data processing means (24) which determines either solely on this output, or in conjunction with the output from other validation means, whether the tested note is genuine or not.

Abstract: Banknotes printed with magnetic ink pass through a tri-color age detector 34, and then between a pair of premagnetization rollers (10,12) having opposite magnetic polarity of such strength that the magnetic signature of all banknotes is enhanced to the same level; the notes are then stacked 50 in an electromagnetic stacker 42. Such notes, having magnetic signatures of the same level, can also be recognized and/or validated by magnetic techniques also.