Artist Eoin Mac Lochlainn goes looking of oak galls (“oak apples”) to make the brown ink used by the Irish monastic scribes.

Sometimes it’s right there under you nose but you don’t see it.  I’ve been looking all over for oak galls this last while, oak galls for making ink but no, any oak tree that I checked, I couldn’t find a single one. Until yesterday – and believe it or not, I found them here on the street where I live.

The dark brown ink used in the Book of Kells was made from oak galls. The monks used this ink in the 9th Century and it is still as clear and dark today as it ever was – so I thought to myself:  I could use some of that!

These galls form on the branches of oak trees when a Cynipid wasp lays its eggs there.  The tree responds by forming a woody shell around the egg but inside, the larva continues to develop. If you see a little hole in the gall (like in the one above), you know that by now, the occupant has grown up and flown away – leaving the little gall behind for scribes (and artists like me) to collect and use to make pigment.

One recipe I found says that, along with the oak galls, you need rainwater, gum Arabic, some vitriol and 3 table-spoons of red wine.  I’m not sure about the vitriol, I try to avoid the internet trolls but everything else seems manageable.  I’ll let you know how I get on.

PS:  someone suggested since that ‘vitriol’ might be the medieval term for iron sulphate