Are Black Spots On Gum Normal - 1960's Issues?

I recently bought some mint Canada stamps from the 1960's.

On many - from several sellers - there are slightly blackened areas on the gum side. Is this typical of this era? On the other hand, if this black stuff is is some sort of damage, I don't want these stamps and will return them. I've never had an issue like this before when buying stamps from ebay - these all came from my first buys on Bidstart; maybe that has nothing to do with it.

Scan shows a couple examples - second is a tagged stamp.








Thanks for your thoughts...

Hello 741opamp. I may be no help at all, but I would guess that the areas on these stamps are just dirty areas. I collect US mainly, but do have quite a few Canadian stamps yet they are not at hand at the moment so I cannot confirm this issue one way or another.

The areas could also be transfered ink from other stamps, or other papers the stamps may have been set down on in the past. Again I probably am no help, but I am pretty sure the black areas should not be there. I am sure the Canada experts will be by soon.

Yes, like mentionned above, it could be an offset from wet sheets stacked together when printed. If not, stamps from that era usually have pristine gum and this could be a form of fungus

Also, I have seen some cases where a very little humidity was sticking stamps together just enough to transfer ink from the face of the second stamp on the gum of the first one. I don't think that those wound be considered as undisturbed gum.

with pepere_jack.

Hi 741opamp:
I have freqiently observed the black markings on the gum of stamps that have been stored in some of the older stockbooks (black pages, of course) or have been mounted on black "art" or "construction" paper. Some of the fibres of the stockbook become stuck due to humidity. I have not discovered a cure or restoration process that doesn't damage the gum.
GJP