Transparent / Clear Window
A transparent non-printed area in the substrate. It is used as a filter for visualizing latent scrambled images when a secondary holder's image is applied to the adjacent page. This feature protects a security document against illegal copying / scanning.
a
b
c
d
e
Fig. 1. Sweden. Passport issued in 2011:
a — page spread (pages 2-3); b — the same. Page 2. Transparent window. Polymer substrate. Transmitted light; c — the same. Page 1. Turning the data page to place the transparent window (marked with a frame) over the secondary holder's image on page 3; d — the same. Zoomed fragment. Transparent window. When capturing the image, a sheet of white paper is placed under the transparent window. The number on the transparent window is laser engraved; e — the same. Transparent window placed over the secondary holder's image on page 3. Invisible personal information (IPI) is visualised with the help of a filter