Pantographs as a Security Feature: Why They Work, Why They Fail

A narcotics case involving an unauthorized, photocopied prescription form containing a “void” pantograph was submitted for examination to the author. The purported “original” prescription form in question was examined and it was quickly determined to be a machine-generated copy, although the “void” warning was not present. Research was undertaken to determine the cause of the failure of the “void” pantograph to appear on the photocopied form. The successful reproduction of the prescription, lacking the “void” pantograph, was attributed to the higher scanning resolution of the photocopier used for the fabrication.