I don't know how they do this. Organics studio makes the hardest sheening inks on earth. period. NOTHING in the history of inks has ever sheened harder than Ralph Waldo Emerson "twilight blue", "Henry David Thoreau", and "nitrogen."
I've got all three and they are freaking magic. They sheen. Everywhere. All the time. ON COPY PAPER. I think twilight blue sheens even harder, but it's hard to tell, these inks are beyond insane. I'd argue that their base color IS the sheen. And they do it with reasonably fast dry times, with good feathering and bleed resistance, and an absolute refusal to smudge.
Writing sample is with a medium flowing wing sung 698 14k gold soft fine nib.
I liked twilight blue a lot, but it was a bit too dark of a royal blue. Nitrogen might be my favorite, because on the face, it's a deep, saturated blue, but under any light whatsoever it FLASHES to an absolutely psychotic purple metallic sheen. I've only ever been complimented on one ink (platinum citrus black) but I get people in class routinely saying "dude that looks insane"
It's not much in the way of water resistance, flow is medium-wet, saturation is super high, but for such a crazy effect, this ink is absolutely usable in everyday writing. It's definitely a blue ink, but it stands out on the page, and I guarantee you have never used an ink like any of these three from O.S.
price is $13/55mL and it comes in a fairly uninteresting brown cardboard box and decent plastic bottle (a little bit nicer than robert oster but I still don't like plastic bottles) so the ink's bottle isn't much of a looker, but you can definitely see where your money goes. This ink is bananas.