[David G4EBT]

During my apprenticeship back in the late 1950s, I spent three months in a drawing office using UNO stencils pens (the type with an ink reservoir and a pin down the fine tubular nib), drawing tracings of large scale OS plans onto tracing paper (known outside the UK as 'vegetal' paper). It was an acquired skill, but the Indian ink wasn't absorbed into the tracing paper, so once dried, and errors could be flicked off the tracing paper with a razor blade and corrected. (The tracing were used as masks in a UV box onto light sensitive duplicating paper).

When Uno pens were used on 'cartridge paper' they didn't make a very neat job as the fibres tended to behave like blotting paper, though that said, ink-jet printers seem to cope well enough on unglazed copier paper.

Every success in your efforts.