NPL scientists develop ink to stop fake passports and currency notes
The Council of Scientific and Industrial Research (CSIR) and National Physical Laboratory (NPL) developed an ink to combat the problem of fake printing of passports and counterfeiting of currency notes. The ink has a new security feature o protecting itself against duplicity
Key facts of the discovery
The ink was produced based on single excitable dual emissive luminescent pigment. It was developed based on the concept of fluorescence and phosphorescence phenomena. Currently, the currency notes display only one color with the emission of wavelength. However, in the ink developed by the scientists features changes in pigment color after the notes are printed.
In ambient light the ink shows white color. When the ink is exposed to UV light, it turns red and when the UV source is switched OFF it turns green.
Why the new ink?
According to the annual report of RBI (2018-19), the risk of duplication of Rs 500 and Rs 2000 notes are higher. The report says that recently launched 500 rupees notes are accounted to 121% of duplication and Rs 2000 notes are accounted to 21.9% duplication.
Fluorescence and Phosphorescence
Both in phosphorescence and fluorescence the radiation is electromagnetic and is spontaneous.
In case of fluorescence, the radiation stops after the source is switched off. On the other hand, in phosphorescence, the glow continues for few hours.
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