Diamine 30ml Fountain Pen Ink Bottle - Registrar's Ink for Calligraphy, Writing & Art | Perfect for Journals, Letters & Professional Documents

This is my second bottle of Diamine Registrar's Ink. I bought a bottle back in 2010, and after two or three years, the color of the ink in the bottle changed from dark blue to a nasty green and I discarded it. I missed the ink, though, so I bought a new bottle. This bottle behaves completely as expected, starts out dark blue when laying down a line, and then gradually, over a few seconds, darkens to a dark gray or black, depending on how wet your pen writes. This ink writes wonderfully in a flex pen, with some nice shading.This is an iron gall ink, so remember never to let it dry in your pen, or you'll need an ammonia solution to clear the dried ink from your pen.