Thin two-dimensional metamaterial layers that allow or inhibit the propagation of electromagnetic waves in desired directions.
A unit of measurement commonly used in authentication when referring to the thickness or gauge of physical substrates and features. One micron is equal to one millionth (10-6) of a metre.
This is print that is so small that it cannot be reproduced by photocopying or scanning, and can only be read under magnification.
Images formed by the superimposition of two patterns with different periodicities, so that they display different visual effects according to the viewing angle.
A method of paper manufacture that drains stock through a mesh cylinder. This is not customarily used for documents like tax stamps due to the weight of the paper and is rather used for banknote paper production.