Transmitted light

The passing of light through an object (as opposed to light reflecting off an object). Watermarks in security paper are usually viewed in transmitted light by holding the paper up to the light source.


A phenomenon whereby materials change colour when their temperature changes, such as when the material is rubbed by a finger to generate heat.


The process of identifying the origin of an item or where it has been.

Track and trace (traceability)

The process of monitoring and recording the past and present whereabouts of a shipment, as it passes through different operators on its way to its destination, through a distribution network.


The process of following an item through the supply chain so its whereabouts are known at all times.