Optically Variable Ink with Embossing
A complex optically variable security element. It contains an image printed by an optically variable ink OVI which plays a role of the background for the second image applied by blind embossing.
A dual optical effect appears when viewed at different angles of observation and illumination: a color change of the background image and visualization of the second image due a treatment of light and the shade which appears at the ridges of relief elements. An image which applied by blind embossing is not visible at a right angle (fig. 1).
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b
Fig. 1. Belgium. Passport:
а — data page; b — optically variable ink with embossing. View at a right angle of observation; c, d — the same image at different angles of observation and illumination. Colour and lightness changing effect of an image applied by blind embossing; e — optically variable ink used as a background and blind embossing applied over it
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d
e