Iron Nut-Gall Blue/Black fountain pen ink made by P.W. Akkerman pen store in The Hague.
This ink is a traditional nut-gall blue black ink, starting as a deep blue, and darkening to a grey-black with blue undertones as the gall bonds permanently to the paper.
Originally made to celebrate their 100th anniversary, this ink comes in a vintage-style 60mL glass bottle with a narrow neck and a marble stopper that creates a well at the top to aid in filling pens, allowing you to get every last drop of ink from the bottle. Akkerman inks work well in all types of pens, modern and vintage alike. It boasts an ideal viscosity and flows well in all types of nibs while available in a great range of saturated colors.