Now, this is where the fun comes in! Here are a few examples with some sort of EFO.

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“Freak” Perforation – Examples: R6c, R51c, R106

“Freak” Perfs are stamps which have extra, or misplaced, perforations on the stamp.  Depending on the rarity and condition (other than the perfs), “freak” perfs can increase the value of the stamp nearly double or triple what it would generally be worth.  Although, it should be mentioned that most, if not all, freak perforations are believed to be forged.  Higher valued revenues with “freak” perfs are usually worth less.

Off-Centered

Off-centered stamps are those with considerable movement of the image off the stamp itself.  In order for it to be considered off-centered by collectors, depending on who you ask, it should be about 20%+ off center.  A minor off-center can be considered poorly printed and have a very adverse effect on value.  Although, the larger the movement, the greater the price it could be worth to an EFO collector.

Pre-Printing Paperfold – Examples: R9a

A pre-printing paperfold simply occurs when the paper the stamp is printed on is folded, even just slightly, and creates a line of which hasn’t been printed on.  The larger the fold, the larger the error.  As for value, the greater the error, the greater the value.  Even small folds can increase the value of the stamp to well above catalog value.  Very low catalog valued stamps can reach prices of over $10.

Imperforation

Imperforation is much harder to judge.  It is nearly impossible to know if there is an imperforation error unless the stamps are in a connected block.  Otherwise, the stamp will be passed off as an imperforated variety.  This example shown here is an example of an error as it is a block of fully perforated stamps.

Double Transfer / Double Impression – Examples: R228a

Double transfer is very much what it sounds like.  The stamp was mistakenly printed twice over by the master die.  These errors are identified in Scott and are listed with a value.

Inverted Portrait - Example: R135b

Inverted portrait, or inverted center, are just that  – an upside down center image.  The error occurs during the printing process of stamps.  It most likely occurs when sheets are transferred during printing.  When there are multiple colors, the sheets must be printed in multiple steps.  Values of known errors are listed in Scott.

Oxidized Color – Example: R15c, R46a

Oxidizing of color on a stamp is most generally caused by direct sunlight over a period of time. This causes the color to change and sometimes fade. This is NOT an error but rather mistreatment of the stamp by a collector. It has a serious adverse effect on price.