TNPSC Thervupettagam

Ink to stop fake passports and currency notes

December 29 , 2019 1667 days 807 0
  • 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 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.

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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