Holograms can provide different levels of security as follows:
Overt - holograms are first and foremost an overt feature, used for the unaided human eye to see them. Their effects can be viewed by tilting or rotating the image, or by moving its position or the light source.
Hidden - image elements that require a non-specific hand-tool to view them, including microtext (which require a magnifying glass or loupe to view) and laser viewable features (that require a laser pointer)
Covert - image element that requires a specific viewer or decoder, including optically-encoded elements (that required a screen or viewer paired to the encoded image) and watermarks (that require s computer scanner to verify the mark).
Forensic - holograms can be combined with numerous types of taggant to create a forensic level which. These taggants are identified under laboratory examination and provide definitive proof that the hologram is authentic. An examination of the underlying structure of the holograms itself can also provide this proof.
Tracking - serialised alphanumeric or other codes can be incorporated into holograms, either by overprinting or within the optical exposure, to provide track & trace capability for combined authentication and supply chain management.