Notes on two-colour riso
Most of what we print uses two drums: a deep teal and a warm red. It is a limitation we chose on purpose. With two inks you stop fiddling with colour and start thinking about shapes, overlaps and the paper itself.
The grain you see on the wallpapers is not a filter added at the end. We scan the test sheets at high resolution and keep the texture of the ink, because a perfectly flat colour field looks dead on a screen.
A practical tip if you are starting out: print a registration sheet before every session. Drums shift a little with temperature, and a two-millimetre misalignment is the difference between charming and sloppy.