Büroservice Bergmann Blaufliessende Eisengallustinte (blue flowing iron gall)

[Thom.]

They also added Indigo, if memory serves me right. The belief was that it would less corrode, the iron nibs, and thus was created the blue black

Yes, that's wrong. The now almost colorless liquid ink was dyed blue with indigo. Chemically, the new inks were more aggressive towards steel nibs than the old goose quill inks. The latter tended to damage the steel nibs mechanically through the formation of crusts. Indigo was later replaced by tar dyes, but the inks were still acidic.

[Thom.]

I looked up Perkins' patent once, that was the first patented tar dye. https://www.penexchange.de/forum_neu...e.php?id=32867
Leonhardi's patent for Alizarin ink was in January 1856, but Henry Stephens https://en.wikipedia.org/wiki/Henry_Stephens_(doctor) had done it 20 years earlier. They simply had an ink that writes barely visible and had to make it visible somehow, one possibility was Logwood and the other Indigo.

[christof]

I still draw a lot with this ink and I work with the effect of ink wash in my drawings.

But my experience is, that there are big differences between the papers in terms of the time it takes for the ink to become completely waterproof.

That's the reason for that I will make different tests with different papers. So here comes the first:

This paper is Royal Talens, van Gogh aquarell paper 300g/m2, 100% cellulose.

IG ink - LAMY Safari by C.M.Z, auf Flickr

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