A friend collected a very large batch of walnut husks that had been browning in her yard for months. I used them to make ink. Above you can see I tried various additives, including gum arabic powder, iron sulfate, and wintergreen oil for preservation.
The color varied between the different formulations, but I mostly found them to be quite nice!
The process of extracting and reducing the ink was very long and made the whole house smell like walnut husk, a very specific smell that is hard to describe.
Paper Fingers Press 