Editing Errors, freaks, and oddities (section)

==Errors==
A '''postage stamp error''' is any of several types of failure in the stamp printing process that results in stamps not having the intended appearance. Errors include use of the wrong colors, wrong [[Denomination (postage stamp)|denominations]], missing parts of the design, misplaced or inverted design elements, etc. The term "error" is typically reserved for obvious failures in the production process that (potentially) replicate over many stamps, while unique errors or poor quality are known as "freaks" or "oddities". Printing plate flaws, such as cracks, wear, or even [[constant flaw]]s, and plate repairs, such as re-entries, are also not considered errors.

Genuine errors are uncommon or even rare; postal administrations have several layers of quality control and inspection, and most printing problems are addressed before the stamps ever reach the public.{{Citation needed|date=February 2024}} A particular error may only exist in a few dozen copies, and some well-known errors, such as the [[Treskilling Yellow]], are considered unique. {{Citation needed|date=October 2015}} They are prized by collectors, with some fetching prices thousands of times higher than the normal stamp of their type.

Errors are known at every stage of production, starting from design, to engraving, to replication of the die, to printing itself, and to perforation. In theory, gumming errors are possible, in practice used stamps have no gum, so any error would become undetectable.

The largest run of an error on a postage stamp is the 2011 United States '[[Forever Statue of Liberty Stamp]]'. The stamp shows the replica of the Statue of Liberty in Las Vegas rather than the original Statue of Liberty in New York. The stamp was released in December 2010 and the error was not noticed until March 2011. The error was identified by Sunipix,<ref>{{cite web|url=http://www.sunipix.com |title=sunipix.com |publisher=sunipix.com |access-date=2013-06-17}}</ref> a stock photo agency in Texas. Ten and a half billion of the error stamps were produced.<ref>{{cite web|url=http://www.postalnewsblog.com/category/stamps/ |title=stamps |publisher=postalnews blog |date=2013-05-23 |access-date=2013-06-17}}</ref>

Collectors understand that a minor error in one stamp catalog might not be considered an error at all in another catalog. Additionally, no definitions of the terms freaks and oddities are universally accepted within the EFO community. John Hotchner has authored many respected articles about this subject that provide clarity.

The following is a list of the major types of errors.
* '''[[Postage stamp design error|Design error]]''': The picture may be of the wrong subject, maps may show wrong borders, the inscription may be factually wrong, text may be misspelled, etc.
* '''Value error''' or ''substituted subject'': A die composed of multiple elements has the wrong elements mixed together, as for instance a low-value denomination being used on a design intended only for high values.
* '''Omission error''': Part of the stamp's design is missing.
** '''Missing color''': Associated with printing processes which print the stamp in several different colors.<ref>United States Scott 1488a, 1488b</ref>
** '''Missing overprint''': A stamp valid for postage only when overprinted but with a missing overprint.<ref>Ethiopia Scott J3a, J4a, and J7a –
in this case the stamps with the overprint were never issued, so neither were valid for postage.</ref>
* '''Double impression''': Stamp, or overprint, was printed twice, one impression offset from the other.<ref>Virgin Islands Scott 18a, Stanley Gibbons 42a; several values of Poland Scott 81-132</ref>
* '''[[Invert error]]''': Part of the stamp is printed upside-down.
** '''Inverted overprint''': The overprint on the stamp is printed upside-down.
* '''Color error''': Stamp is printed in the wrong color(s).
* '''Paper error''': Stamp is printed on the wrong type of [[postage stamp paper|paper]] which, e.g., may have a different [[watermark]] or color than intended.
* '''Perforation error''': Perforations are missing on one or several sides or put in the wrong place (e.g. diagonally). As perforations may be removed by cutting them off, imperforate errors are collected in pairs.

<gallery class="center">
Austria 1850 9kr 5IIIa paper fold.jpg|A diagonal paper fold (Austria 1850).
Image:Santander 1886 Sc6b error.jpg|Cliché error pair, right stamp with “Cinco” instead of “Diez" (Santander 1886).
Image:1899and1902-SpecialDelivery-Error.jpg|An embarrassing design error. In 1899 the US was occupying and furnishing postage stamps to Cuba. The Spanish word "inmediata" was misspelled on this stamp  ("immediata"). This was corrected when the Cuban Republic had it reprinted in November, 1902.
Image:Washington stamp 5c error 1916-20_issues.jpg|5-cent value error, with a 5-cent die wrongly placed in a 2-cent sheet (U.S. ca. 1917).
Image:Costa Rica Revenue 1870 F4a.jpg|50 centavos color error, green instead of red (Costa Rica 1870).
Image:Stamp US 1962 4c Dag Hammarskjold invert.jpg|Once the yellow-inverted error [[Dag Hammarskjöld invert|Dag Hammarskjöld]] memorial stamp was discovered, 40,270,000 were printed to prevent speculation. Only the original unintentionally printed specimens are considered to be errors. (U.S. 1962)
Image:Uruguay 1892 Sc100a.jpg|Inverted overprint (Uruguay 1892).
Uruguay 1883 Sc51 B4 HI.jpg|Missing horizontal perforation (Uruguay 1883).
</gallery>