Please help: which ink is this?

[outofgamut]

I’ve inked one of my Twsbis with a blue ink a long time ago and have forgotten which ink I used.

It’s a very well behaved dark blue ink with a lovely red sheen to it and I want to put it into one of my broad Viscontis. Well - if I remembered which one it was…

I know I may be asking quite a bit but can anyone wager a bet? I’ve got quite a few Troublemaker and Robert Oster inks but I can’t seem to find this one.

Help greatly appreciated!