does anyone know how to scale up DIFFUSION in digital watercolours?

I work at 300 to 600 dpi on A3 or A4 papers.... for print, naturally.
at this size the paper textures can be scaled to 200 to 400dpi to look the same as the equivalent physical media.

HOWEVER, one of the best features of the digital watercolours is ALWAYS lost  because it doesn't scale up to print size.
It does't change when the DPI changes, so it remains a treasure seen only on 1:1 screen resolution.
What is it?
Diffusion: that delicious bleed of wet paint into the grain when Diffusion is tweaked to full on digital water colour paints.  

In my 15 years of painter I've never found a way to overcome that, to scale it so it can be seen and enjoyed in print.
Is there an answer?

Would LOVE to know!!