The process of printing the serial numbers on Canadian notes has always been separate from the printing of the rest of the note design. That means different equipment is used for the printing of serial numbers.
Has anyone noticed that the style and size of numbers and letters on the multicolour notes (1969-1980s) is the same as on the Bird series notes (1986-2000s)? The multicolour notes have red and blue serial numbers while the Bird series notes have black serial numbers, but the font and size of the digits is exactly the same. The type and colour of ink used does not require a change of equipment between series. So I have to believe the same numbering machines were used to print serial numbers on both series.
As well, the Journey series notes have the same style and size of numbers as the short-lived 1979 series $5 and $20 notes. Did anyone else notice that? The 1979 series was supposed to be a radical departure from conventional numbering practices, and it was. The numbering machines used for the multicolour series had only 10 reels to accommodate a 7-digit serial number and either a 2-letter prefix (with or without an asterisk (*) in front) or a 3-letter prefix. The numbering machine for the 1979 series had 11 reels to produce a sequence of numbers that was meant to be machine-readable, or so the theory goes. For a number of years in the 1980s, the bank note printers evidently used two types of numbering machines for different denominations, and it's enigmatic that the Bank of Canada went back to the older technology for the Bird series, but evidently they did. Perhaps they realized the old machines with whatever limitations existed still suited their numbering practices.
The old numbering practices dating back to the multicolour series continue to be used to this day (7-digit serial number, 3-letter prefix). However, for the Journey series and the current Frontiers polymer series, it looks like the printers are using the numbering machine designed for the 1979 series. There's nothing inherently wrong with using a machine capable of printing 11 characters to print only 10 characters. It just means 1 reel never gets used. And we know that there are no limitations on what-characters-can-be-printed-where because hundreds of millions of consecutively-numbered $20 notes of the 1979 series were made. Maybe it was easy to adapt the machine from one format using only numbers to another using numbers and letters. The extra reel is there but it never prints anything. Maybe some day, we'll have notes with a 4-letter prefix or an 8-digit American-size serial number, who knows? Apart from the similarities in size and style of characters between the 1979, Journey and Frontier series, there's another bit of evidence that just jumped into my mind to make me believe the printers are using the same numbering machine for all these series...
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A few collectors have found Journey series error notes with mismatched serial numbers where a black rectangle appears immediately to the right of one of the serial numbers. If you ask me, that's evidence of the 11th reel, the one that is always supposed to be blank. Well, in a machine malfunction, it can rotate too, though why a black rectangle appears, and not something else, is a mystery. As far as I know, nobody has found an error note with an extra character like a number or letter, indicating that these characters exist on the 11th reel. If such errors were ever made, they would be quite rare and would almost certainly have been noticed by the machine operators or quality control inspectors. Notes with black rectangles are exceedingly rare.
As far as I know, this subject has never been discussed before. Did someone beat me to the punch and publish similar hypotheses elsewhere? And what do you think of the idea of old printing technology being used to make our modern plastic notes?
Here is an image of a 1979 series note for comparison purposes:
{http://wiki.cdnpapermoney.com/images/1/1b/BC-53aT_33000137347_R.jpg}