underprint

The addition of colour under black areas to produce a deeper black and prevent oversaturation of the paper.

Printing underneath the main design of a stamp, intended to prevent forgery or removal of the postmark.

a logo or advertising printed on the underside of a stamp; backprint.

A fossilised print in the rock bed that is at a deeper level than the track the creature leaving it was actually travelling on; caused by the pressure of a heavy animal or penetration of the sediment by a pointed appendage.