Of Stamp Gum and its Originality - How to Authenticate Gum
Lastly, this 5c value, which is perforated 12, is from the last printings made after 1864. It is very similar to the gum on the Newfoundland stamps above, but is a bit shinier. I would describe it as colourless, evenly applied and semi-gloss.
However, it is important to look at more than one set to understand the gums that the American Bank Note Company used. So lets take a look at the Nova Scotia Cents Issue that was printed at the same time as the New Brunswick Issue above:
I mentioned in an earlier post that the 1859-67 Cents of Canada:
The only drawback to the above tests I find is that you can have a stamp with genuine original gum where the gum has either been re-distributed or sweated, or otherwise disturbed that can fail tests 1 and 3. So you really do need to have some familarity with the gum normally found on the stamps printed by a particular printing firm at a particular time. After a while you will get a 6th sense about whether the gum "looks right".
Any questions, comments?