Canada Medallion Question On Gum?

I have several MNH stamps from the 1932 KGV. I noticed there is a big difference on the the gum. I know there were wet and dry printings. Which gum would be the wet and which the dry? Did the Canadian post office use gum breakers or is this typical of the way the gum was applied?

I don't have an answer to your specific question but I have seen weird things happen to gum from the type of storage. For instance, a gorgeous plateblock collection was put in black Vario style pages with an odd raised bump pattern. This transferred to the gum. I have also seen lines like that caused by extreme humidity, although not quite that closely spaced.

I have many admirals and have never seen gum like that, though, so I would lean towards a storage issue. However, I will let an expert comment further.

To the best of my knowledge, wet and dry printings have a result in a larger and smaller stamp of the same design. The wet printings will shrink and be a mm. or two (or less) smaller than the dry printed counter part.

As far as the gum is concerned, I don't think this has a bearing on that but I could be wrong.

Chimo

Bujutsu

I believe what you have is a difference in printing methods: flat plate (your left stamp) vs. rotary press (right stamp).

I read the wet printing had gum that was applied after printing where as the gum on the dry printing was applied before printing. The gum on the right stamp looks like gum breakers.

My Scott catalog doesn't have a note regarding the press used. Is there a price difference? Does it matter to collectors? I just saw the note after 177 that says "No. 169 rotary printing is distinguished unused from 169a flat plate printing by the former having gum ridges about 5mm apart." I take this to mean that they were using different presses at the time and some values were made on flat plate press and others on rotary press. Nothing to do with wet or dry printing. I wonder if all of the 2 cent Medallion KGV stamps were printed with a rotary press and if all had gum ridges?

Your right would be like 1847bill noted the 169a caused by the printing process and I think simular to US gum breakers but not as intentional (could be way off on that). However had you not mentioned the series they came from storage would be the next best explanation. Humidity going up and down can cause gum to crack/ break and of course stick to everything in a pile. Ziplocks seem to make sense but unless your in arizona or an extremely dry all year long area it can be a nightmare.

I believe the stamp on the right is the result of improper storage. It looks like it may have been stored in a place where there was high humidity and curling may have occurred. It looks like the result of flattening after it had curled. I don't believe gumbreakers were used on this issue.

Stamps printed by the British American Banknote Company (BABNC) and issued from 1930 to 1934 were printed by wet (Stickney) rotary press or by dry flat plate press. The wet rotary press stamps had gum breaker lines on the gum side while the dry flat plate stamps had embossing on the gum side. Canada Scott/Unitrade # 169 was printed by wet rotary press while Scott/Unitrade # 169a was printed by dry flat plate press.

Interestingly, the rotary press stamps are perforated around 11.20+ x 10.90+ while the flat press stamps are perforated 10.90+ x 10.90+ which is due to one same bar and wheel perforator being used for rotary press stamps and two different wheel perforators being used for the flat press stamps. The bar gives the 11.20+ perforation while the wheels give the 10.90+ perforations.