Z Grill

Z Grill

The Benjamin Franklin Z Grill, or simply "Z-Grill", is a 1-cent postage stamp issued by the United States Postal Service in February 1868 depicting Benjamin Franklin. While stamps of this design were the common 1-cent stamps of the 1860s, the Z-Grill is distinguished by having the so-called "Z" variety of a grill pressed into the stamp, creating tiny indentations in the paper. Although the 1-cent Z-Grill is generally cited as the rarest and most valuable of all US postage stamps, the 15-cent Lincoln Z-Grill is just as rare and the 10-cent Washington Z-Grill scarcely less so. All three of these stamps were produced at the same time, along with more common Z-grill versions of the contemporary 2-cent, 3-cent, 5-cent and 12-cent stamps (The earliest known postmarks on Z-grill stamps date from January 1868). The "Z" pattern, unique among grill templates used by the Post Office because it incises horizontal ridges into the stamp rather than vertical ridges, was replaced within a very short time, for stamps with the D- and E-Grills were already being postmarked in mid-February.

The purpose of grilling was to permit the canceling ink to be better absorbed into the stamp paper, thus preventing reuse of stamps by washing out the cancellation marks. The use of grills was found to be impractical and they were gradually discontinued after 1870.