A Fascinating Philatelic Specialty

Freaks and errors are stamps not prepared according to their design specifications and mistakenly released to the public.  Errors are stamps which have mistakes in color, perforation or design.  Freaks are stamps which show an inconsistency in their production.  There are three groups of stamps listed here: misperforated freaks, imperforate errors and missing color errors.
Misperforated freaks are stamps with perforations falling within the boundaries of the stamp’s design, rather than in the margins, usually caused by simple mechanical problems.  With imperforate errors the perforation stage of production is completely omitted.  The presence of a single mark from perforating machinery would disqualify it as a true error.  This happens rarely and usually involves human error.