A security feature used in most banknotes. It consists of variations in paper density and thickness which cause variations in its opacity. As a whole, these variations form an image, integrated in the paper, which is visible against the light. Due to its variations in thickness, a watermark also has palpable raised print.
Withdrawal of banknotes from circulation
The process whereby unsuitable used banknotes are withdrawn from the notes and coins in circulation. National central banks are responsible for deciding when a banknote is not suitable for circulation. Unsuitable banknotes are rendered useless or destroyed by the national central banks.