Optical device

A hot stamping foil comprising a carrier layer and an optical security device releasably secured to said carrier layer, said security device comprising a number of layers including an optically diffracting layer including an embossed layer and an at least partially reflective layer which together generate a first image;

• and a non-optically diffracting second image defined within the device in association with said first image, wherein said second image is provided at an interface between the embossed layer and said at least partially reflective layer.

A method of constructing an optical security device for use on a security article, the device comprising a number of layers including an optically diffracting layer having an embossed layer and an at least partially reflective layer which together generate a first image, the method comprising bonding said layer together and providing a non-optically diffracting, second image within the device wherein said second image is provided at an interface between said embossed layer and said at least partially reflective layer.