It's called "foxing", and is a type of fungus. Be wary of buying stamps/collections when you find stamps with this damage. It can pass onto album pages and other stamps.
I found a way to help eliminate this from stamps. The discussion link is here:
https://stamporama.com/discboard/disc_main.php?action=20&id=12994
I agree that foxing can spread and stamps with foxing should be kept away from clean page/stamps. And I agree that ammonia can curb foxing.
But the issue is that ammonia is also used to remove manuscript postmarks and there are ways to detect if a stamp has been exposed to ammonia. If you send in a stamp for certification that has been treated with ammonia they will detect it and note it on the cert. (It is considered a chemical alternation.) But folks can certainly alter the stamps they own if they wish. I will leave it to other to decide if selling a stamp treated with ammonia (without telling the buyer) is ethical or not.
Preventing foxing has a lot to do with maintaining a good environment. Heat and moisture can accelerate foxing. A cool, dry and stable storage environment is paramount; temperatures should be held at a constant 70°F with a relative humidity held between 30% and 50%.
Don
I recently purchased an album with used US stamps from time frame 1980-1990. The stamps were kept in what was looking to be high quality mounts. But many stamps have yellow, even brown colors around the edges. Few have yellow spots on the back.
By soaking some it seems that color will fade away, but not completely.
What is the reason for that and how this situation can be prevented?
Again, thanks.
re: Yellow or brown colors, sometimes something rusty on the edges of a stamp
It's called "foxing", and is a type of fungus. Be wary of buying stamps/collections when you find stamps with this damage. It can pass onto album pages and other stamps.
I found a way to help eliminate this from stamps. The discussion link is here:
https://stamporama.com/discboard/disc_main.php?action=20&id=12994
re: Yellow or brown colors, sometimes something rusty on the edges of a stamp
I agree that foxing can spread and stamps with foxing should be kept away from clean page/stamps. And I agree that ammonia can curb foxing.
But the issue is that ammonia is also used to remove manuscript postmarks and there are ways to detect if a stamp has been exposed to ammonia. If you send in a stamp for certification that has been treated with ammonia they will detect it and note it on the cert. (It is considered a chemical alternation.) But folks can certainly alter the stamps they own if they wish. I will leave it to other to decide if selling a stamp treated with ammonia (without telling the buyer) is ethical or not.
Preventing foxing has a lot to do with maintaining a good environment. Heat and moisture can accelerate foxing. A cool, dry and stable storage environment is paramount; temperatures should be held at a constant 70°F with a relative humidity held between 30% and 50%.
Don