Election ink

Electoral ink, indelible ink, electoral stain or phosphoric ink is a semi-permanent ink or dye that is applied to the forefinger (usually) of voters during elections in order to prevent electoral fraud such as double voting. It is an effective method for countries where identification documents for citizens are not always standardised or institutionalised. One of the more common election ink compositions is based on silver nitrate, which can produce a stain lasting several weeks. It was first used during the 1962 Indian general election in India. The ink was developed by Council of Industrial Research-National Physical Laboratory of India and manufactured by Mysore Paints and Varnish Ltd. It is exported to more than 30 countries.