Every banknote counter and currency detector on a specification sheet lists a string of detection abbreviations: UV, MG, IR, CIS, sometimes DD or MT. To a procurement officer they look like interchangeable badges; to a service engineer they are completely different physical measurements, each catching a different family of counterfeit. Buying the wrong combination means either paying for layers your cash mix will never use, or - worse - shipping a machine to a customer whose local forgeries slip straight through the one layer it does have. This guide explains what each technology actually measures, what it cannot catch, and which combination fits each type of cash business.
Counterfeiters work with whatever printing technology they have: colour copiers, inkjet printers, offset presses, or genuine notes chemically washed and reprinted. A colour copier cannot reproduce fluorescent fibres, so ultraviolet inspection catches it. An inkjet forgery has no magnetic ink at all, so a magnetic head catches it. But a high-quality offset counterfeit on genuine paper stock can pass both - which is why credible machines stack independent layers and raise an alarm when any one layer disagrees.
Genuine banknote paper is designed not to fluoresce, while embedded security fibres and specific printed patches glow in defined colours under ultraviolet light. A UV sensor floods the note with UV and reads the reflected fluorescence: a bright overall glow means ordinary paper, i.e. a fake. UV is inexpensive and catches the crudest forgeries - home-printed and photocopied notes - but it is blind to counterfeits printed on genuine or washed paper stock, and strong ambient light can weaken its reading, which is why detectors hood the UV chamber.
Most currencies print specific areas with magnetic ink - patterns that are part of the design but invisible to the eye. A magnetic head reads the distribution and strength of that magnetism as the note passes. Because reproducing the exact magnetic pattern requires the original ink and printing process, MG is a strong authenticity check, and it also enables denomination recognition on value-counting machines, since each denomination carries a different magnetic signature. Its limit: some currencies and some denominations carry little or no magnetic ink, so MG coverage must be verified per currency, not assumed.
Under infrared light, parts of a genuine note disappear and other parts stay dark, according to how the inks absorb IR. An IR sensor pair (emitter and receiver) reads that pattern as the note travels. IR catches forgeries that pass UV and MG - particularly offset prints on genuine paper - because the counterfeit inks absorb infrared differently. Like MG, IR patterns are currency-specific, so a machine’s IR layer is only as good as its firmware library for the notes it claims to support.
A Contact Image Sensor is a linear camera: it photographs the entire face of the note at high resolution as it moves, and the processor compares the image against stored templates. CIS is the only layer that sees the note the way a human does - portrait, watermark position, printed micro-text, series and version - which is why CIS machines deliver mixed-denomination value counting, orientation and facing detection, and version sorting as by-products of the same image. Dual-CIS designs read both faces simultaneously. The cost side is real: CIS machines are more expensive, and their accuracy depends on keeping the sensor glass clean and the template library updated when a central bank issues a new series.
Width, length and thickness sensors are not authenticity checks in the strict sense - they are transport integrity checks that also catch half-notes, chained notes, doubled notes and folded corners. A note that is the right size but made of the wrong paper still needs UV/MG/IR/CIS; a genuine note fed double still needs the dimensional layer to stop the count error. In practice every serious machine combines both families.
Easy-Banker manufactures currency detectors, UV/MG/IR bill counters, CIS value counters and mixed-denomination sorters, coin machines and bundling equipment for distributors in the USA, Southeast Asia, South America, Africa, the Middle East and Europe. Detection configurations are quoted per market: we build the sensor stack and firmware set around the currencies your customers actually handle, and OEM/ODM programmes cover logo printing, custom firmware and manual languages. Send us your target currencies and cash mix and we will return the detection matrix, datasheets, MOQ terms and lead times with the quotation.
