SECURITY DEVICE AND METHOD

摘要

A security device comprises a substrate (1) having a viewing region (2). A first pattern (3) of a first colour (A) and a second pattern (4) of a second colour (B) are printed on one side of the viewing region (2). A third pattern (5) of the first colour (A) and a fourth pattern (6) of the second colour (B) are printed on the other side of the viewing region (2). The first and second patterns (3,4) on the one side of the viewing region overlap the fourth and third patterns (6,5) 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.