Thanks to John for his fourth and final review. I've enjoyed his reviews, and I hope you have too! If you're interested in sharing with others about your favorite inks, email me and we can talk about it. ~Brian Goulet
Diamine Prussian Blue
Prussian Blue is one of my favorite blues, the other being Cerulean, so I was very excited to get my hands on Diamine's Prussian Blue fountain pen ink. This ink review was done with a Pelikan m205 with Binder Italifine nib, which has a 0.9mm cursive italic on the front side and fine round tip on the backside of the nib. It is a pretty wet writer, so YMMV when using this ink in fountain pens with varying flows. The paper used is 90g Clairefontaine in the small Unplugged Staplebound Duo, which is excellent.
The flow of the ink is excellent, though almost anything flows in this wet writer. But, having used this ink in many different pens, I can say that it does flow very well. It also shades well in both wet and dry writers, so if you hate shading this won't be the ink for you. I, on the other hand, love shading, so it's just another plus for me. There is no bleedthrough or feathering on this paper.
You can also see below how the ink looks on a wider nib (0.9mm cursive italic) and a narrower nib (fine round tip). I usually use this ink in a somewhat wet medium nib and it writes a tiny bit darker than the fine nib sample below. Some people see green in this ink, but I don't.
I have found the drying time for the ink to be excellent in most cases. That said, a wet writer on Clairefontaine paper is going to take a good bit longer as the image below shows. Yet, the fine tip dried very quickly even on the Clairefontaine paper, which matches my real life experience with it.
As far as water resistance is concerned, it's not really suited to withstand water. I didn't do any soak test, but I did drop of few drops of water on the page and wipe it off with a napkin, which is probably what I would do if I got water on my notebook while writing at a cafe. For those instances, the ink seemed to fare decently. At least I can still read the text. Note that the ink was fully dried before applying the water.
Diamine Prussian Blue is available in 2ml samples and 80ml bottles at GouletPens.com.