Does anyone know of a publicly available overview of the fountain pen ink manufacturing industry? I've seen market reports available, but they're for sale, and I'm not buying -- I'm curious but not THAT curious.

I started to wonder because Birmingham Pen Co. has some interesting ink colors (Or maybe I'm just overwhelmed by the interesting names? Like Allegheny Arsenal Gunpowder Black and Pennsylvania Railroad Boiler Steam Blue-Black?), and I've got a few samples. They claim to hand-make the ink in their Pittsburgh facility. They also say the inks are manufactured in Germany. I wonder what that means.

Over the years I've seen all sorts of claims (always unsubstantiated) that one manufacturer makes another brand's inks. I would not be surprised to learn there are only a few companies actually formulating and manufacturing inks while supplying them to many different brands. It's openly known, of course, about relations between Sailor and Bungu Box and a few other open relationships. But I don't have any overall answers for the whole marketplace, and I haven't found any answers in research I've done so far. Anyone know?