Security device and method

Abstract

A security device comprises a substrate having a viewing region. A first pattern of a first colour and a second pattern of a second colour are printed on one side of the viewing region. A third pattern of the first colour and a fourth pattern of the second colour are printed on the other side of the viewing region. The first and second patterns on the one side of the viewing region overlap the fourth and third patterns respectively on the other side of the viewing region whereby a) when each side of the viewing region is viewed in reflected light, the patterns on that side can be distinguished by at least their colours, and b) when the viewing region is viewed in transmitted light, from either side of the substrate, the viewing region is sufficiently transparent that subtractive colour mixing between the overlapped different colours results in a perceived single resultant colour being visible.

Dependencies are inferred from the claim text.