underprint

Adjective

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

Noun

 * 1)  Printing underneath the main design of a stamp, intended to prevent forgery or removal of the postmark.
 * 2)  a logo or advertising printed on the underside of a stamp; backprint.
 * 3)  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.