Waterproof Inks
I am very pleased to report that the waterproof black inks I recently purchased have given me no trouble at all in my fountain pens! When I use watercolour paints or water-soluble pencils on sketches drawn with these inks, no black ink is released by the water and brush.
Pilot Security Black is marginally darker than Platinum Carbon Black - although this is only apparent when the inks are carefully compared side by side. I'm using Security ink in a regular DPP-100 Pilot Desk Pen, and the Carbon ink in a Platinum Carbon Pen. Sometimes the Pilot won't start on the first stroke, but that's the only thing I've noticed. Neither ink appears to settle or do anything unwanted inside the pen.
Ujuku were out of Sailor Kiwagura stock, so I should get that ink in a couple of weeks, but so far I'm thrilled - these inks have worked out perfectly!