Importance

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Abstract

This invention relates to holograms employing colour addition techniques, and to methods and apparatus for the fabrication of such holograms. The holograms are particularly useful for security applications.A volume reflection hologram storing at least two images, the hologram comprising: a first stored image configured to replay at a first wavelength; a second stored image configured to replay at a second wavelength different to said first wavelength; wherein said first and second images at least partially overlap when replayed together; and wherein said first and second wavelengths are selected such that where said first and second images overlap they give the appearance of a colour defined by a third wavelength different to both said first and second wavelengths.

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First Claim