This year I collected a bunch of fallen walnut fruit and made ink and stain. It was pretty easy to make - just about 20 rotten walnuts simmered for about 5 hours in water. So far I've used it to stain leather and paint in my sketchbook. I added gum arabic powder to thicken the ink and sodium benzoate to preserve it.
It's a beautiful color. Unfortunately, walnut ink is fugitive, so it's something for my sketchbook and not for the art pieces I sell.











