The condition of a stamp, used to grade postage stamp

Postage stamp

A postage stamp is a small piece of paper that is purchased and displayed on an item of mail as evidence of payment of postage. Typically, stamps are made from special paper, with a national designation and denomination on the face, and a gum adhesive on the reverse side...

s in the stamp collecting

Stamp collecting

Stamp collecting is the collecting of postage stamps and related objects. It is one of the world's most popular hobbies, with the number of collectors in the United States alone estimated to be over 20 million.- Collecting :...

 market, is superficially expressed by how well centered the stamp is and how wide the margins of the stamp are:

• Extra fine (EF) or extremely fine (XF) is a perfectly centered stamp with wide margins.
  • Superb is sometimes used for a perfect stamp.
• Very fine (VF) is a well centered stamp with ample margins.
• Fine (F) is a stamp that is significantly offset up or down or to one side but still has four margins.
• Average (Avg.) is a stamp that is has no margin on at least one side with a portion of the design trimmed off or cut into by perforation
  Postage stamp separation
  For postage stamps, separation is the means by which individual stamps are made easily detachable from each other.Methods of separation include:# perforation: cutting rows and columns of small holes...
  
  s. Except for rare or very old stamps average stamps are not collected or sold except as space-fillers or reference copies. Heavy cancellations which obliterate the design can also be considered.
• Poor Only great rarities such as the British Guiana 1c magenta
  British Guiana 1c magenta
  The British Guiana 1c magenta is regarded by many philatelists as the world's most famous stamp. It was issued in limited numbers in British Guiana in 1856, and only one specimen is now known to exist....
  
  , a stamp which is heavily canceled, soiled, and cut to shape, are collected in poor condition.

Many other factors besides centering and margins determine the description and value of stamps. Key among them in the case of mint stamp

Mint stamp

In philately, a mint stamp is a stamp which is in its original state of issue, is unused, has never been mounted and has full gum, if issued with gum. The term applies equally to postage stamps and revenue stamps.- Variations :...

s is the presence or absence of postage stamp gum

Postage stamp gum

In philately, gum is the substance applied to the back of a stamp to enable it to adhere to a letter or other mailed item. The term is generic, and applies both to traditional types such as gum arabic and to synthetic modern formulations...

 and whether the gum has been disturbed:

• Mint never-hinged (MNH or Mint NH, or just NH) is a unused, mint, stamp that has full original undisturbed gum, that has never been attached to an album page with a stamp hinge
  Stamp hinge
  In philately stamp hinges or mounts are small, folded, transparent, rectangular pieces of paper coated with a mild gum. They are used by stamp collectors to affix postage stamps onto the pages of a stamp album.- Use :...
  
  . Modern stamps are collected in this condition and older stamps sell at a considerable premium if they are in this condition.
  • u/m: unmounted mint (mint never hinged) with full gum (Stanley Gibbons).
• Lightly hinged (LH) is a mint stamp which was hinged with a modern stamp hinge which has been removed leaving only a slight disturbance to the gum.
• Heavily hinged (HH) is a mint stamp which was hinged with an old-fashioned stamp hinge the removal of which has damaged the gum, or which cannot be removed.
  • Hinge remaining (HR) is a mint stamp which has part of a stamp hinge on the back.
• Original gum (OG): A stamp with the gum it was issued with, however deteriorated by age.
• No Gum (NG) Stamp has been soaked and the gum washed off, rarely, stamps are issued with no gum.
• Regummed (RG) Fresh gum, sometimes very like the original gum, has been applied to the stamp. If regumming is done in a clumsy way it is possible to detect it by examining the end of the perforations under a microscope where the fresh gum may interfere with the small strands of torn paper or even form small droplets.

Stanley Gibbon, which has vast experience in describing and selling older mint stamps uses the following to describe stamps with disturbed gum:

• large part o.g: mounted mint (mint hinged) with the majority of original gum
• part o.g: mounted mint (mint hinged) with under 50% of original gum

Postally used stamps usually have no gum and these terms do not apply. An apparently used stamp with gum, for example from the former Soviet Bloc, may be Cancelled to order (CTO) and have little or no value to collectors.