I have an A3 (Australian page sizing from what I know) black and white pen illustration that I was to enlarge into A1 or thereabouts (about a meter tall) the line work is fine enough that if I were to scan at 1200+ dpi, or even 2400 dpi I should get the quality needed for such an enlargement.

What I want to do from there, is print it multiple times onto watercolour paper so I can try multiple colouring options using watercolour, or other forms of paint without ruining the original artwork.

The only option at the moment that I'd normally go with is scan the image, then paint a watercolour background onto another sheet, then scan that, and combine the two digitally.
But in that manner, I wouldn't get the detail in the watercolour so if I get around to printing up to a meter, it'll be obvious the watercolour background is greatly enlarged

Anyone know of a press that would be able to do something like that? Inkjet printing wouldn't work I don't think, and not sure if a laser printer would either. Maybe a screen print or silkscreen onto watercolour paper?

Anyone have any idea? I'd greatly appreciate it!