I see examples of this stamp described as oxidized with the color changed from orange to brown. I have not noticed many, if any, other stamps described this way. Is this the inevitable outcome for all US Scott #C1 stamps? Or is it due to improper storage? How do I avoid this happening? Thanks.


  • 6 Comments sorted by Votes Date Added
  • edited June 15 1 LikesVote Down
    More accurately, that is called sulfurization, a chemical reaction of the orange ink with sulfur in the air. It is actually oxidation that will restore the natural color, in the form of a hydrogen peroxide rinse.
  • Ted's Right, but if it has gum on the back Don't Rinse it!!!!
  • Thanks gentlemen, I was guessing there was iron in the ink and it was rusting. Instead, it is tarnishing like silver. And the sulfur comes from... Paper? The air? Fingers? Where?
    How can it be prevented?
    I am guessing it deflates the price.
    Are there other stamps prone to this?
  • edited June 16 2 LikesVote Down
    The sulfur is in the atmosphere. Think acid rain, which is atmospheric moisture acidified by the atmospheric sulfur. The sulfur comes from coal-burning power plants, cement producers, and from smelting plants for metallic ores containing sulfur. Any color can be be darkened through sulfur exposure, though orange and yellow are the most prone to this because of metallic compounds in the ink.
    I'm not sure about preventive measures. I don't know if enclosure in Showgard style mounts is sufficient to mitigate against atmospheric exposure.
    Yes, the color change will adversely affect the value, of mint stamps anyway, because gummed stamps cannot be treated without disturbing the gum.
  • Tobacco smoke causes it too.

    The stamp has more value with the sulphurization removed. On stamps with gum, the treatment will remove the gum, but the bright orange color should return.

    This may also occur on stamps with yellow, red and brown color pigments. Orange stamps are the easiest to treat, from my experiences.
  • H2O2 (sometimes diluted) judiciously applied with an artist's brush, blotted and removed by doing the same several times with distilled water can oftentimes preserve most of the stamp's gum. Others have used a 'sweat box' with H2O2 as the humidifier with some success.
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