Oh boy, where do I even start. Some time ago I decided to buy a second pen. I wanted something cheap to use with a document ink. Because my choises of ink were quite limited (and still are), I decided to pick Koh-I-Noor Document Blue as

• relatively cheap ink,
• relatively well-behaved ink (allegedly),
• bottle says it's blue.

As for the pen, I decided to buy Kaweco Perkeo with M nib size for no particular reason, besides nice nib quality (allegedly), and it being basically overgrown Kaweco Sport, which people say is a good pen.

And well, I kinda hate and love this duo at the same time.

First of all - colour. It's nice shade of blue, if you filling your converter as intende. Which means inserting it inside the pen and then dipping the nib in ink.

Otherwise the colour of ink will be a bit different. You can say it's blue, but not quite. It's too soft and pastel for it's own good. Especially when you consider that officials don't like different colours when you're signing documents.

To be fair it's indeed a document ink. It's fairly water-resistant. In my tests water didn't blur the ink very much, and in the rubbing test Koh-I-Noor surrendered, when the paper started to wear out, so in that regard the ink is adequate.

And speaking of it's water-resistance, as any other document ink, Koh-I-Noor Document Blue will clog your pen when you don't write with it frequently enough. Well, at least write once a week with it, or your pen will start skipping.

Speaking of the pen, you definitely need to wash it before use, or it will burp ink when converter is half-full. When I didn't wash the nib and feed properly, I was experiencing skipping, and colour was a bit dull.

Nib is good. Lines are thinner than Lamy Safari M nib, and it writes smooth.

So in conclusion, maybe I just need to use another ink in my Perkeo. But for now it works.