Someone the other day was insistent with me that Sailor Kiwaguro #fountainpen ink was not water resistant (smeared easily) even after drying for over half an hour. They might as well have told me the sky was ivy green. It was coming out of a fine nib pen, was on watercolor paper, and the amount of water was just drops from a brush. Any theories / corroborating experiences? It has to be the paper, right? But I know a lot of people who use it on watercolor paper generally.
@johns
With any nanoparticle ink some pigmen will not be entangled in the paper fibres and will wash away with water. This is often used as the basis for claims that the ink is not water resistant. It is a total furphy by people who wilfully won't do their research properly.
If you can still read the text after the excess is washed away then the ink is water resistant.
@johns I’ve heard a variety of experiences, but people seem to consistently recommend Platinum Carbon Black over Kiwaguro for watercolors