The present invention relates to improvements in security devices that can be used in various authenticating or security applications, and in particular to an optically variable security device which can be viewed under low light conditions. The security device comprises a light deflection structure having a first side and a second opposing side. A colorshifting layer is applied to the first side of the light deflection structure and a reflection layer is applied to at least a first region of the second side of the light deflection structure so as to provide a strong reflection in a direction substantially parallel to the incident light source when the direction of the incident light is at an angle away from the normal to the security device. The security device has at least one second region in which the reflection layer is absent, said first and second regions defining indicia.