Many things

[der Mouse]

> (Are your bills still all the same size, or have you copied everyone
> else and made the larger dominations bigger to stop people bleaching
> small bills to print big ones?)

Not quite everyone else.  Canadian paper money is still all the same
size independent of denomination.

We have, however, recently started issuing new $20 notes (and
presumably higher denominations) with metallic inks and raised printing
and watermark pictures and such that are approximately impossible to do
with consumer-grade printers.

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