Canada's Early Blue Paper

I wonder if this blog's philatelic mavins could explain why the 5¢ Victorias and Edward (#70, #79, #91) were on bluish paper, but not the Jubliee (#54) nor the Admiral (111)? What was the purpose?

I am not sure if this would be similar to blue paper on U.S. stamps which has to do with rag content in the paper while the Canadian bluish paper may have more to do with the blue ink infusing/diffusing into the paper more than usual. See: https://goscf.com/t/6958

I believe an answer for your question is as follows.

In roughly 1878 The British Commonwealth associated with the UPU (which includes Canada) and some European countries decided to standardize local, country and international rates etc. as per colour coding.

In Canada the scott 70...scott 91 as you have shown was part of the colour coding...At the time 5 cents was the international mailing rate. Also the scott 54 jubilee stamp to.

As far as bluish colour paper was used...I would image back then the printers had blue paper sitting aside ready to use for stamps designated for international use.

And I think the American stamps we also part of the UPU decision and I believe their's are 5 cent stamps to.

Does that make sense..?

Robert

I like Wert's answer, but... that would mean that the Newfoundland stamp at the same time (the 5¢ harp seal) might be on bluish paper. Is it?
Are any other international rate commonwealth issues blue on bluish paper?

Sak, the scott 40 harp seal was issued between 1876 - 1879...NFLD was not part of Canada till the mid 1900s...Probably did not have to abide by UPU process...Just my opinion.

Robert

Colored paper can be found in any number of colors. Since color is added to the pulp, the color is present throughout the paper. To identify colored paper, examine both sides of the stamp including the perforated edges.

That is what I always do..

Robert

Wert: Newfoundland was part of the Commonwealth, though not in the Canadian Confederation!
Haven't found any other examples of bluish paper.

Could be they did not want to go with the new process or did want the new process by UPU..remember we were not there to see what really happened.

Robert