How to spot a counterfeit bill

The kind of corrupt world we live in uses all kinds of means to exploit people, fake money or cash being one of the primary schemes. Nevertheless, with the use of some tools and Chemistry, we can detect easily detect these forgeries.


Tools needed for detection

  1. The first thing we need is an anti-counterfeit detection pen. It works like a regular highlighter but since it contains Potassium iodide and elemental iodine, these two can help reveal the use of regular printer paper as it contains starch. (The combination of iodine components react with starch and turn blue) Real money, on the other hand, is made of cotton and linen which don’t react to iodine. They are threaded with tiny red and blue fibers, something that is used only by the highly guarded ‘Crane & Company’.
  2. Another method involves the presence of a strip on the bills, that appears fluorescent under UV light. It’s a polyester strip with invisible ink on it and it only extends to a width of 1 mm. Its location varies from bill to bill.

The Chemistry behind this revelation

  1. The science behind the first method is that starch constitutes two molecules, one of them being Amylose. The structure of this molecule is basically a long chain of sugar molecules and its appearance is similar to DNA’s helical structure. As soon as iodide comes in contact with Amylose, it gets trapped inside this coil. This leads to the creation of a dark coloured compound, thereby revealing the fake bill.
  2. However, fake bills aren’t always printed on starch-containing paper. The second method that uses the polyester strip as a breakthrough device, contains molecules, like any other Matter. So, once its exposed to UV light, it absorbs some amount of energy causing these molecules to reach an excited state. On returning to their original state, they start losing some energy in the form of heat and the remaining energy is emitted as light. Since ENergy is inversely proportional to wavelength, the strip gives off lower energy leading to longer wavelengths in the visible range. This how what once was invisible becomes visible. If the light doesn’t show up, then it means that the bill you’re holding is fake.

Other simple methods to spot a fake include focussing on the portrait, which should appear life-like and not flat. The seal should have even sawtooth points, the inked border should be intact and the individual numbers of the serial number should be equally spaced out.

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