In the world of art supplies, a liquid medium like ink is pigment + binder + solvent. Pigment is color. In iron gall ink, the black pigment is created by the chemical reaction when vitriol (iron sulphate) is added to water that had gall-nuts steeping in it.
The binder holds the ingredients together. You might remember the Egyptians got the sap, or gum, from acacia trees which they dried and ground into powder—Gum Arabic. Gum Arabic is the binder for iron gall ink. The powder is mixed with vinegar before adding it to the inky water.
The acid from gall-nuts (and vinegar, too) eats into the vellum very slightly, so the pigment stays put.
Water is the solvent. You can thin iron gall ink with water. After it dries, though, it’s waterproof. If you goof you have to scrape it off with a knife.
Here are links to iron gall ink recipes:
Isn’t she wonderful? This lady found a medieval recipe for iron gall ink and decided to cook it up herself:
Here’s where you can get the ingredients online. CHECK WITH YOUR PARENTS before you start playing with caustic chemicals that can burn a hole through the kitchen counter, you weirdos!
There’s a charm in the old words of these recipes. They were once used to describe chemicals and today they describe attitude or a way of speaking or acting:
Back to the beginning of The Western Civ User’s Guide to Reading & Writing.