Could a chemist reproduce inks of medieval quality, then apply them to vellum?

[Oscroft]

I’m starting to think we mean the same thing, but we’re talking at cross-purposes.
I’ve now read so many websites about historical inks, which has only made things more complicated.

I'm far from being an expert in historical ink technology, just have a bit of interest in it through liking 'proper' writing  So this is just a few comments from reading this recent interesting discussion... based on my own imperfect understanding, so additions/corrections welcomed...

There are indeed inks that use iron but which are not iron gall inks... if there's nothing included to provide tannin (the galls), the iron-tannin reaction that produces the black colour doesn't happen. And an iron gall ink can fade over time to a more brownish rust-like colour too, so it can be hard to be identify - especially as there are so many possible combinations of ingredients. So, evidence of iron in a sample is not necessarily evidence of iron gall ink - though the absence of iron can help exclude it.

I think calling gum arabic (or other similar materials) a binder can perhaps be a bit misleading. It can have the property of binding pigments to some surfaces - especially less absorbent ones. But as I understand it, its essential use with inks made for quills and parchment/paper is to thicken the ink a bit so the quill can hold more, and make the ink flow better in a thicker layer. The iron-tannin compound in gall ink itself binds well to parchment and paper fibres.

I've seen reference to McCrone quite a bit, but I can't find a source of their actual work - every link I've found is dead. Does anyone have a working link?

Finally, as an aside, I found some ferrous sulphate in a cupboard here yesterday... it's no spooky event, I just remembered I'd used something for dealing with moss in my lawn a few years ago and had half a memory that's what it was.

I have no oak galls, but I do have tea and there's plenty of tannin in that, so I tried making some ink. I didn't want any gum, as I want to be able to use fountain pens. The result is a workable ink which quickly develops a pleasing dark grey shade, and which will presumably darken a bit further with time. I might add a bit of thickener to a small sample (no gum, but I have some honey) to see if that works better with a dip pen. Thanks for the inspiration, folks!