Security device including microimage elements

A security device having (i) an array of microimage elements that vary in material composition and (ii) a corresponding array of sampling elements, the array of microimage elements and the corresponding array of sampling elements together exhibiting an optically variable effect, the security device being formed by:

• applying a first region of a layer of a first material to a surface of a first material carrier;
• applying a second region of a layer of a second material, different from the first material, to a surface of a second material carrier;
• blending together the first and second regions of the layers of first and second materials such that a blended region of the layers of first and second materials exhibits a gradual change in relative concentration of the first and second materials along a first direction, the step of blending together the first and second regions of the layers of first and second materials comprising:
• bringing a first blending surface into contact with the first material on the surface of the first material carrier and moving the first blending surface relative to the surface of the first material carrier along a direction corresponding to the first direction to spread the layer of first material along the direction corresponding to the first direction;
• and
• bringing a second blending surface into contact with the second material on the second material carrier and moving the second blending surface relative to the surface of the second material carrier along a direction corresponding to the first direction to spread the layer of second material along the direction corresponding to the first direction;
• bringing the blended layers of first and second materials in the blended region into contact with a patterned material carrier, a surface of the patterned material carrier defining a pattern corresponding to the array of microimage elements, the patterned material carrier selectively removing the first and second materials in at least the blended region in accordance with the pattern;
• and
• transferring the blended layers of first and second materials defining the array of microimage elements on to a support layer so that the array of microimage elements of the security device are overlapped by the corresponding array of sampling elements in such a manner that the array of microimage elements and the corresponding array of sampling elements together exhibiting an optically variable effect.