diamine majestic blue ink
I have had some believable recommendations for Diamine Majestic Blue, so I decided to try a bottle. You can see the results to the right, there; the full page is with a Lamy 2000 B nib, as part of my NaNoWriMo effort, and the other is part the same pen and also another Lamy 2000 with an M nib.
The colour of this ink is extremely pleasant - and this is speaking as somebody who doesn't generally like blue inks. It's distinguished, vibrant and noticeable without being garish. The ink has a lovely metallic reddish sheen as it dries, too, which shows when the light is at certain angles. It flows extremely well, generously and reliably.
It would be pretty much a perfect ink if it wasn't for the fact that it smears not only just after it has been written with, but for literally days afterwards, even with a dry finger. For my NaNoWriMo I was writing on 90gsm Oxford paper, which is relatively "shiny" though not amazingly so; no other ink I used had that problem to anywhere near that degree. I did try it on several other papers, for example my Habana journal, with the same result. The ink seems to sit on top of the paper forever instead of properly drying and settling in.
I'm afraid I can't use an ink that smears to that degree. You can see the smearing on the NaNoWriMo page - that wasn't due to any sort of effort on my part, just opening and closing the book, moving my hand across it occasionally while counting words perhaps. It's a shame, since apart from this smeariness it's pretty much perfect, with a gorgeous colour and a lovely feel when writing. I may experiment in the future with diluting it, which might possibly help the smearing issue.