Received some great feedback on this over private message. Sharing here as well.
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The printing quality tends to be lower with off-register printing and hence the prices for Canadian editions of several us books, not just EC comics, tend to be 50-75% of their American counterparts.
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Dell books were printed by Wilson Publishing of Toronto. They are always 36 page books so they are almost always cut down from the 52 pages of the US edition but have no ads.
Most if not all DC books are printed by either Simcoe Publications or National Publications of Canada and are also 36 pages so if they are reprinting a 52 page US books they have no ads but the interior is usually missing one longer story and substituted with another with less pages in it from another DC title. The lack of ads could mean more story pages that a US one with lots of ads within the 52 pages.
Canadian comic companies Superior and Bell Features printed both reprints and original Canadian content depending on the year (1941-56) and the reprints generally had a mix of Canadian ads and US ads, but the US ads almost always have the mail order square blanked out.
There were some ads and some 52 page books from some of the smaller reprint publishers like Export,Ace International, F.E. Howard, Better Publications of Canada etc.
Its hard to generalize since over that time period many companies popped up and went away, there are odd ball prints that looked almost like the US version with more pages, all US ads but were published by some unknown printer.
I estimate there are as many as 2400 books that were printed in Canada in that era from 1941-56 and I have 1480 with over 800 of them with the content indexed and all splash pages,filler and ad pages scanned.
In terms of collectability and value:
Print quality can be poor in lots of books, either all of its interior or just a page or two, some stories are in there but cut down in pages with text summaries at the bottom to make up for the missing pages in the story.
Some are desirable as Variants and many have different interiors than the cover suggests or unique covers and titles and you don't know which US title it is reprinting.
For example: Batman 59 he US issue is 52 pages and has the first Deadshot story. The Canadian issue, same cover except "52 big pages" is not on the cover, is 36 pages and no Deadshot story.
Canadian reprint comics are scarcer because a lot less were printed, since most were only distributed in Canada so they can command higher or lower prices. It all depends on the buyer.
That's the story of Canadian reprint comics in a nutshell
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