The condition of a stamp is important in determining its value and possible investment potential the better the condition, the more the stamp is likely to appreciate in value, especially if it is rare or already valuable.
Stamps in Mint Condition
The finest condition is called “mint.” This is a stamp that is in the same state in which it was bought at the post office, there are no marks or blemishes, and the gum is intact. It has not been mounted using a stamp hinge but has been persevered as new.
The next category is “unused” this stamp has not been used to post a letter and so has not been through the postal system, it has no cancellations or postmarks but although identical in most ways to a “mint” stamp the gum to fix the stamp to the envelope is missing.
A mint stamp is worth more than an unused one.
Other Stamp Conditions
Look at the front of the stamp are the colors bright and fresh or dull and faded? The brighter, the better. USPS recommends to ask these questions. Like, is the stamp clean, dirty or stained? Look at the edges of the stamp. The perforations, are they intact or are some of them missing? Look at the corner perforations particularly to see if they are even and regular.
The stamp should not be torn or nicked as these are not considered collectible. Although they may be used as “fillers” to complete a set. And then thrown away when a better, more intact example is added to the set.
Where the image of the stamp is framed with a white border and does not “bleed” out of the edges; look for what is called “centering.” Is the stamp’s image in the center of the frame or is it shifted to one side or the top or bottom of the stamp? Centered stamps are better than those that are off center.
If the stamps have been through the postal system and had a cancellation, postmark or a frank. If it has been used to send a letter, it will have received a cancellation at the sorting office. Collect used stamps that have only light marks and not ones that are heavily obliterated with the black cancellation stamp.
Thinning and Fine Conditions
Turn the stamp over to the blank or gummed side and look at the condition of the stamp. Are there parts where more light is showing through than other parts? This is called “thinning” and is due to the stamp having been mounted with a hinge and the hinge being carelessly or roughly removed. Thinning can also be caused when removing a stamp from paper and not having soaked it first.
Other categories that stamp dealers and collectors use are “very fine” and “fine,” both of which refer to stamps that have been hinged and suffer a degree of gum removal from the hinge.