Recommend a Blue with these Properties

[KrazyIvan]

You know, I've used quite a bit of Namiki Blue and didn't bother to buy more when I ran out because it was rather "blah" in regular pens (on Rhodia; office-supplied printer paper it was almost identical to Tsuyu-kusa) and it had a habit of staining my converters. I don't recall if I ever tried it with a flex nib.

This is a good suggestion, though, because the FA will be used almost exclusively on office-supplied printer paper and I could care less if it stains this Con 70 since I'm looking for a dedicated pen/ink combination. I'll have to get a sample to try out to see if it flows well when flexed.

Aha, well, at least you've already tried it. I have to confess that I haven't personally had any problems with staining, but that could be dumb luck. I've also never had a good answer nor picked up a sample of plain "Pilot" blue to compare if they are the same inks. The ink I am specifically referencing comes like this:

When I first bought a bottle of Namiki Blue, it was purely because I bought it on clearance from a local store that was shutting down. I was not going to turn it down for $7. I used it in a 1.1mm nib pen and was unimpressed. I left the bottle sitting for quite a while until I recently inked a fine nibbed pen and was wowed. With that said, I'd say if the OP is going to use the pen without flexing, they might be surprised.

[welch]

Maybe Parker Quink Blue with Solv-X? I have just started using a bottle of older Parker Blue, maybe from the mid-50s (judging from the lettering on the box and the metal cap). Great stuff. It has saturated itself, just a bit -- now darker and without the purple hint. This seller seems to have Washable Blue and Permanent Blue. I have the Permanent, which has decorated my index finger and is stubborn about washing off. (Permanence is not necessarily a feature, but...)

I got mine from this Ebay offering: https://www.ebay.com/itm/NOS-Vintage...IAAOSwwf5Z0lWF

NOTE: ink more than 20 or 40 years old will vary in color, just from evaporation. Quink and Skrip were the most popular inks in the US, judging from how many bottles, nearly full, are still around. Therefore: while I would not assert that any of the old inks will look like this or that, another bottle of Permanent Blue from the same seller probably will look like what I bought.

Incidentally, Monteverde Horizon Blue is, with he Quink Blue, my favorite blue ink this week. MVHB looks a lot like the Parker Penman Sapphire that I've got.

[titrisol]

Maybe Parker Quink Blue with Solv-X? I have just started using a bottle of older Parker Blue, maybe from the mid-50s (judging from the lettering on the box and the metal cap). Great stuff. It has saturated itself, just a bit -- now darker and without the purple hint. This seller seems to have Washable Blue and Permanent Blue. I have the Permanent, which has decorated my index finger and is stubborn about washing off. (Permanence is not necessarily a feature, but...)

I got mine from this Ebay offering: https://www.ebay.com/itm/NOS-Vintage...IAAOSwwf5Z0lWF

NOTE: ink more than 20 or 40 years old will vary in color, just from evaporation. Quink and Skrip were the most popular inks in the US, judging from how many bottles, nearly full, are still around. Therefore: while I would not assert that any of the old inks will look like this or that, another bottle of Permanent Blue from the same seller probably will look like what I bought.

Incidentally, Monteverde Horizon Blue is, with he Quink Blue, my favorite blue ink this week. MVHB looks a lot like the Parker Penman Sapphire that I've got.

THANKS FOR THE TIP!
PS. I received the ink today, bottle looks good... box disintegrated
This must be 50s/ 60s vintage :0

PPS The smell is awesome, ink behaves very well and the color is nice and saturated
One of the classic boring dark blue color for business.