Latent Image KIPP
(from German kippen – to tilt)
An image which consists of parallel lines that are perpendicular to the lines of the background. The latent image KIPP is applied using the intaglio printing plate and appears as an achromatic image in sliding light at an acute angle of observation. It can be visible due to the shadows cast by the raised lines of surface relief. When the document is rotated by 90° without changing the angle of observation, the latent image KIPP becomes either light, or dark compared to the background color.
Fig. 1. Scheme of observing the latent image KIPP
a
b
c
d
e
Fig. 2. Kuwait. Passport issued in 2017:
a — front endpaper. Paper substrate; b — the same. Area with a latent image. Latent image is almost invisible. Viewed at a right angle of observation and illumination; c — the same. Zoomed fragment. Parallel lines of the latent image are perpendicular to the lines of the background. Intaglio printing; d — the same. Latent image KIPP. Viewed at an acute angle in sliding light; e — the same. Viewed when the document is rotated by 90° without changing the angle of illumination and observation