The Gum Types On The 1967-1973 Centennial Issue
Overview
The topic of gum on the Centennial issue is one that has not received very much attention at all since collectors became aware of the basic difference between dextrine and PVA gums. However, like any chemical compound, the composition of the gum on this issue showed considerable variation as the post office experimented with different formulas as they transitioned away from dextrose gum towards synthetic PVA gum. Indeed the special hybrid gum, termed "spotty white gum" by collectors, that first appeared on a limited basis in 1971 was almost a cross between dextrose and PVA in the sense, that it had most of the properties of PVA gum, but it possessed much of the shine and thickness associated with dextrose gum. In addition to variations within the three major categories of gum, there was also a significant difference in the properties of the gum used by the British American Bank Note Company (BABN) on the stamps that it printed, and the gum used by the Canadian Bank …
The topic of gum on the Centennial issue is one that has not received very much attention at all since collectors became aware of the basic difference between dextrine and PVA gums. However, like any chemical compound, the composition of the gum on this issue showed considerable variation as the post office experimented with different formulas as they transitioned away from dextrose gum towards synthetic PVA gum. Indeed the special hybrid gum, termed "spotty white gum" by collectors, that first appeared on a limited basis in 1971 was almost a cross between dextrose and PVA in the sense, that it had most of the properties of PVA gum, but it possessed much of the shine and thickness associated with dextrose gum. In addition to variations within the three major categories of gum, there was also a significant difference in the properties of the gum used by the British American Bank Note Company (BABN) on the stamps that it printed, and the gum used by the Canadian Bank …