How can I tell if a stamp has been regummed?

Look for differences in gloss or texture, brush marks, gum that does not reach the paper edge, and uneven pooling around design elements. Use a loupe and compare the back to authenticated examples of the same stamp issue.

What does 'hinged' mean on a stamp description?

Hinged indicates a stamp shows evidence that a paper hinge was once attached to the back. That evidence can be a small remnant of the hinge, a mark, or a disturbed area of gum; hinged stamps normally have lower value than those described as Mint never hinged: undisturbed gum.

Does original gum always mean Mint?

Original gum abbreviated OG simply means the gum is the stamp's original application. An OG stamp can still be hinged or damaged; 'Mint never hinged: undisturbed gum' is the specific term indicating the gum has never been hinged.

How to Identify Stamp Gum Condition

This guide shows how to inspect and classify the gum on postage stamps so you can identify condition, spot regumming or hinge marks, and understand how gum affects stamp value in philately.

Quick facts

Mint NH: Mint never hinged: undisturbed gum
Original: Original gum abbreviated OG

Why gum condition matters

Gum is the coating on the back of a stamp that allowed it to adhere to an envelope. Collectors and dealers judge stamps partly by gum condition because it directly affects value. A stamp with intact gum can be worth more than the same design with a disturbed or missing gum. In philately, identifying gum condition is a routine part of evaluating a stamp.

Tools and workspace

Work on a clean, flat surface with good, even light. Have a magnifier or loupe (10x is typical), a bright lamp, and a soft brush. A dry, flatbed scanner can help record the back of a stamp for later comparison; avoid using a scanner that requires pressing the stamp. Use tweezers or stamp tongs to handle stamps; do not touch the gum with fingers.

Step-by-step inspection

1) Handle the stamp with tongs and view the back at several angles under a lamp to see sheen and texture. 2) Look for uniformity across the gum: consistent texture and gloss usually indicate original gum. 3) Check for hinge marks, small areas where a paper hinge was once attached, and for thins or creases that break the gum layer. 4) Examine the edges and perfs: regumming often stops short of the paper edge or shows brush lines. 5) Use a loupe to check for tiny ridges or bubbles in the gum surface that can indicate regumming or repairs. 6) Photograph or scan the back for a reference file.

Common gum conditions and terms

Know the standard descriptions you will see in catalogs and dealer notes. Mint never hinged: undisturbed gum describes a stamp whose gum shows no sign of having been hinged. Original gum abbreviated OG refers to gum that is the stamp's original factory application, even if it has been hinged. Other common conditions are hinged (visible hinge remnants), regummed (new gum applied), partial gum, and no gum.

Signs of regumming and repairs

Regummed backs can differ in color or sheen from the stamp paper, show brush strokes, or have gum that pools unevenly in recesses. Regumming can fill thins or cover minor faults; compare the suspected stamp to authenticated examples of the same issue when possible. Use transmitted light (backlighting) carefully to reveal pasted repairs under the gum and to check for paper fibers disturbed by re-gumming.

Storage and preservation

Store stamps in a dry, stable environment away from direct sunlight and strong humidity changes. Use albums with archival-quality pages or glassine interleaves. Avoid mounting or pressure that could disturb the gum. When moving or transporting stamps, keep them flat and protected in stockbooks or rigid holders to prevent impressions on the gum.

Using a digital identifier

After you have inspected and documented gum condition yourself, you can use a digital tool to help compare images of the back to reference examples. Stamp Identifier can scan or accept images you take and offer visual matching and condition notes; use it only after you complete a manual inspection.

Common questions

How can I tell if a stamp has been regummed?: Look for differences in gloss or texture, brush marks, gum that does not reach the paper edge, and uneven pooling around design elements. Use a loupe and compare the back to authenticated examples of the same stamp issue.
What does 'hinged' mean on a stamp description?: Hinged indicates a stamp shows evidence that a paper hinge was once attached to the back. That evidence can be a small remnant of the hinge, a mark, or a disturbed area of gum; hinged stamps normally have lower value than those described as Mint never hinged: undisturbed gum.
Does original gum always mean Mint?: Original gum abbreviated OG simply means the gum is the stamp's original application. An OG stamp can still be hinged or damaged; 'Mint never hinged: undisturbed gum' is the specific term indicating the gum has never been hinged.

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