Abstract: A security device comprises two or more regions (1, 2). Each region (1, 2) contains a material or combination of materials wherein the two or more regions exhibit substantially the same visible appearance under first viewing conditions and different visible appearances under second viewing conditions, the second viewing conditions. The second viewing conditions comprise a combination of a) visible light and b) substantially any UV wavelength.

Abstract: A security device comprises a substrate (40) having a reflective portion which is provided with a raised line, structure (6), the line structure defining a plurality of segments (4a, 5a . . . ), each segment being formed by a respective set of substantially parallel raised lines. The Mines of at least three segments extend in different directions. Each line is formed by or carries an ink (7) which does not extend fully into the spaces (8) between the lines or which is sufficiently translucent between the lines so as not to obscure the reflective surface between the lines, wherein each segment causes incident light to be reflected non-diffractively in a variable manner as the angle of incidence changes.

Abstract: A security device comprises two or more regions (1, 2). Each region (1, 2) contains a material or combination of materials wherein the two or more regions exhibit substantially the same visible appearance under first viewing conditions and different visible appearances under second viewing conditions, the second viewing conditions. The second viewing conditions comprise a combination of a) visible light and b) substantially any UV wavelength.