[bebna]

If you get your hands on it:

Rohrer & Klingner dokumentus or sketch-ink

First one is certified document proof, the others work the same, just that the used pigments are not as hardened against chemicals to allow strict iso certification.

They are both fast at drying and once dry, won't give a inch to water. Not even coloring the water and marking the rest of the paper, where it flowed.