This is a nice, smooth-flowing blue-black. It's more blue than black, but with a bit of vintage tone. Of course, the cartridge works well in my Kaweco Sport, but be patient since it can take several minutes for flow to begin. However, that's normal for many cartridge-type fountain pens. If you desire a darker blue-black with more black than blue, in an international short-sized cartridge, try Pelikan blue-black.

Blue black is my favorite ink color overall. It's a good all-purpose color but distinguished. This version flows well, and is smooth, but it's a tad lighter than I like. Still, I'll buy it again, because it doesn't appear that I can get my favorite blue-black in a cartridge: Pelikan. I also really wish the Kaweco inks were available in a large capacity size, but I understand why since their pens are shorter and take the international size cartridges.

Love my Kaweco pen but not really loving this ink. Too blue and not saturated enough to make me happy. I like blue ink; I like black ink: thought I would like blue-black ink, but not so much.
Everything I have written with this looks sort of old, faded, and not so easy to read. Just no "life" to this color.

Perfect deep blue, far more sophisticated than the standard blue with its memory of school fountain pens.

I love the many colors available for my Kaweco Ice Sport Fountain Pen. Nice ink, bold, smooth, dries quickly, and is pleasant on the page. I love writing now. Thank you, Jet Pens!