Interesting
Yes, acids in the gum cause it to turn brown. As stamps age, this is becoming more and more prevalent on stamps. Scott states in Iranian listings that such toning is to be ignored as regards to value, since so many Iranian stamps have toned gum due to the acidic nature of the gum. If find similar on many post WWII issues of France and French colonies
Stamps from any tropical or sub-tropical region can show "aged", "honeyed" or toned gum. It's an atmospheric effect. Stamps with pure white gum have, most likely, never been to the countries they represent!
Front scans?
Logic suggests removing gum from early stamps makes sense. The reality of stamp values suggests not.
Won a small mixed lot of early Barbados. Going through them, I am finding many of them look like maybe toning has taken hold on the complete rear, or is this some kind of gum yellowing?
re: Are these stamps evidencing toning?
Yes, acids in the gum cause it to turn brown. As stamps age, this is becoming more and more prevalent on stamps. Scott states in Iranian listings that such toning is to be ignored as regards to value, since so many Iranian stamps have toned gum due to the acidic nature of the gum. If find similar on many post WWII issues of France and French colonies
re: Are these stamps evidencing toning?
Stamps from any tropical or sub-tropical region can show "aged", "honeyed" or toned gum. It's an atmospheric effect. Stamps with pure white gum have, most likely, never been to the countries they represent!
re: Are these stamps evidencing toning?
Logic suggests removing gum from early stamps makes sense. The reality of stamp values suggests not.