In modern bank notes they widely use dyes which are perceived at sight as dyes of the same colour but have different reflection in infra-red spectrum range. Such an effect is called as IR-metamerism of dyes. If a drawing is made with two dyes identical in hue but different in properties, than in IR-range of spectrum one will see only a part of the whole drawing corresponding to the zone coated with the dye reflecting IR-rays.
One CIS or two? That single choice decides whether a banknote counter can only authenticate a note - or actually read it: denomination, series, fitness, serial number. A distributor guide to contact image sensors, the serial-recording rules spreading acro
India's RBI issued a Master Direction on Note Sorting Machines (2 Oct 2026): only BIS-certified machines may be used, and obsolete models must be retired by 30 June 2027. Here is what banks and distributors must do - and which machines comply.
Bangladesh is replacing a full series, Oman printed its first polymer rial, and commemorative polymer notes landed in the Pacific and Africa in 2026. Here is what each issue demands from counters, sorters and detectors - and how distributors should stock
