The security thread was introduced for the first time in India.
Microprinting and security threads were introduced in the 1991 currency series.
The security thread has dark edges visible on either the front or back side of the banknote.
Hold your bill to light and look for the embedded security thread.
The bills also have embedded security threads and ink that changes from a copper color to green when they are tilted.
As an added security feature, all notes have a vertically embedded security thread.
The security thread glows green when illuminated by ultraviolet light.
Different types of security threads are also present in each banknote.
They should also have a raised print, a watermark, a security thread and a see-through number.
In genuine notes, the security thread is incorporated into the paper at the time of manufacture.