See-through Register
An image the parts of which are printed on the front and reverse side of a page. In transmitted light, image elements on the front side are complemented by the elements printed on the reverse side. As a result, a complete image is formed without any obvious shifts, overlays or gaps.

a

b

c

d
Fig. 1. Serbia. Service passport issued in 2008:
a — page spread (pages 16-17). Paper substrate; b — the same. See-through register, the front side. Offset printing; c — the same. See-through register, the reverse side. Offset printing; d — the same. See-through register. Transmitted light. The elements on the front and reverse side of the page are combined to form a whole image without gaps, overlays, and shifts