I started making Oak Gall ink in 2006 and have made 2-4 batches of ink every year since then. I became interested in it because of my love of doing calligraphy from the pre-17th century. Of course the more interested I became in doing that calligraphy the more I wanted to try out using the materials that the scribes of the time would have used. Ink, quill and parchment are still the iconic images we draw up when we think of writing and especially of scribes. So I became interested in making the ink and using it.
This is not a journal or a scientific paper detailing my experiences. Instead it is general summation of my thoughts and experiences.
When making Ferrous Oak Gall Ink I have mostly worked with these four ingredients.
- Oak Galls
- Ferrous Sulfate
- Binder, which is usually Gum Arabic
In short you boil or soak the Oak Galls, strain out the liquid, add the Ferrous Sulfate and then add the binder. That description accurately shows the overall simplicity of making Ferrous Oak Gall Ink. It does not convey the parts that folks might consider tedious such as bottling the ink, measuring amounts, straining can be an interesting experience and you should wear clothes you don't mind staining.
On the right hand side of this page you will find links to various Ferrous Oak Gall Ink Recipes. Look them over and you will see that some recipes call for red or white wine instead of water, sometimes honey is used as a binder, stuff called Green Vitriol, or Copperas is called. Crushed eggshells may be added as well to help temper or neutralize the ink.
Let's explore ink making a bit more.
In the pre-1600 time period the science of Chemistry did not exist. The scientific method and science as we think of it today did not exist either. People in that time period did not have the understanding of the world and how it worked that we have today. And vice versa to be fair. So a chemical compound that we today call by its component parts would not have been called that in pre-1600. Sooooo....
FERROUS SULFATE = COPPERAS = GREEN VITRIOL
Ferrous Sulfate is a moist blue-green odorless crystal. (I have also used it in a white powder form). It was believed that because it was greenish in color that it had copper in it and was called copperas in several areas and times. However, one of the ways ferrous sulfate was made by first pouring water over sulphurous earth and then pouring that solution over iron such as nails. There was also the name Green Vitriol which was different from Blue Vitriol. Blue Vitriol does contain copper. I don't know when, where or why copperas and green vitriol changed usages or if they were interchangeable and contemporary.
So why put crushed eggshells in ink?
The work "Ink" comes from Late Latin "encaustum," from neuter of Latin "encaustus," meaning "burned in", from Greek "enkaustos", verbal of "enkaiein" meaning "to burn in."
Umm what does "to burn in" have to do with ink? And with putting eggshells in ink?
"Ink" and "Caustic" both share this same root word. If something it caustic, it is acidic. So ink is acidic? Yes, even today many of our inks are acidic. Some are pretty neutral and some are even basic. (For a quick description and commonly known items that are acids and bases click here)
Oak galls have tannic acid in them. No this is not the same as the tannin in your tea. When you are boiling or soaking the oak galls you really are freeing the tannic acid from the oak galls. Yes, you are creating an acidic solution; it's a weak acid but an acid nonetheless. Well this creates a problem because if you put acid onto your writing surface, eventually it will eat holes through your writing surface. This is actually a problem as many old surviving books are slowly degrading. This problem may have been noticed pre-1600 and they found that if they added crushed eggshell it would decrease the problem.
Because eggshells are composed of approximately 95% calcium carbonate (CaCO3). Calcium carbonate is a base. What happens when you put an acid and a base together? They act to neutralize each other. That is to say they head toward that neutral 7 on the Ph scale which means the ink becomes less acidic. Less acidic ink means fewer problems with the ink eating through the surface you are writing on.
Is this a good ink to write with?
Absolutely. It was used for over one thousand years and you can even find modern recipes for Ferrous Oak Gall ink being mixed and made for the United States Postal Service.
How permanent is it? Very. We have a plethora of "western" manuscripts available to us written using Ferrous Oak Gall ink; most manuscripts I know of are written in Oak Gall ink. The two acids (Ferrous Sulfic (aq) FeII(SO4) and Tannic acid (aq)) turn instantly black when they come in contact with each other. Tannic acid turns black when it comes in contact with the air and Ferrous Sulphic turns black when exposed to air and light.
If you are using a large nib, say a C-2 or larger, the ink turns black almost instantly on the writing surface. Using smaller nibs and the ink goes on a light gray. If you are using a really small nib say a Mitchell 5 or smaller it goes on so light that it can be almost invisible. My experience has shown that it darkens within 30 seconds to readable and can take up to three weeks to finish turning completely black.
Does this ink go bad?
Not in my experience though I have run across sources that say it will. I have ink I made in Novemberish of 2007 that I periodically take out and test. It is still working wonderfully.