A few years ago I went to a tiny but excellent exhibition all about ink at University College London, where a video was showing about how to make ink from oak galls. It’s been in the back of my mind ever since, so when I found myself camping under a line of oaks on the Gower in south Wales last week with oak galls dotted all over the grass, it seemed as if the time had come to give it a try. (oak galls – or oak apples – are little hard balls made when a parasitic wasp larva injects certain chemicals into developing leaf buds on the oak tree).

A little bit of research on the internet showed the key ingredients of this ancient ink (first known recipe by Pliny the Younger) are oak galls and iron, with gum arabic as a binder. The dark colour is created by a chemical reaction between the tannic acid in the galls and the iron sulphate. There’s a very informative website here. There are all sorts of minor variations, so I decided to create my own hybrid method, and here’s how it went:

Firstly, I put all the oak galls in a plastic bag and used a hammer to break them up. Then I ground up some out-of-date iron tablets I found in the cupboard, and threw in some old chunks of iron I found on Chiswick Eyot last week when learning about fish for Thames 21 (but that’s another story…). I put it all in an iron pot with some rainwater, and set some heat under it on the stove. Amazingly, it was only a couple of minutes before this orange soup turned a proper inky black. I boiled it all for a few more minutes, then strained it through an old tea towel. Finally I added the gum arabic, which gave the mixture a nice viscosity. In all I made half a pint of ink, which has a good dark brown colour – and once you’ve put it on paper, it continues to darken for a few hours. (the labels on the bottles are written with the ink)

It’s been a very interesting experience – much easier than I thought it would be to get a good result, and definitely something I would do again. I don’t know how long the ink will last, but I’m certainly going to start using it for drawing right away. Big thanks to Humphrey (age 4) for collecting all the galls for me!

I’ve just come back from a few days in Durham, working on a very exciting project with a team from the Royal Festival Hall. Pull Out All The Stops is a campaign to restore the spectacular organ at the RFH, all 7,500 pipes – the restoration is now almost complete and will be celebrated with a huge organ festival next spring. Two lucky primary schools have been involved throughout, with the Year 5 classes visiting both the RFH and the workshop in Durham which both built and restored the organ, Harrison and Harrison.

My role has been to work with the two schools to produce a children’s guide to the organ, for and by children, and I will post more on this nearer the festival. Last week I felt very lucky to visit Harrison and Harrison with children from the school in county Durham, as well as a film-maker and an animator – the results are going to be fabulous! The children spent a day drawing then filming with Sam, and another day animating with John from Skidaddle Films – this was very inspiring to watch and made me really want to experiment more with film. We also had a great time inventing a board game (based on snakes and ladders), which will be part of the festival next spring.

It was thrilling to get to see how an organ is made, up close – the metal room was particularly exciting, as we were able to watch old pipes rapidly disappear into a furnace and emerge on a giant ladle as a shining river of molten lead. Dotted throughout the workshop were cauldrons of honey-like glue….I particularly loved the description of the visit one boy wrote the following day: “The smelly golden glue, sprinkling out like golden syrup out of the hot pot in steaming water falling. Saws chopping, drills cutting, metal hammers banging loud.”

There’s a lovely notice in the foyer of the workshop – Mr Harrison’s Instructions, dated 1883. Looking after the organ is important: “Should the keys get dusty, as they surely must from time to time, do not begrudge a few moments to clean them. What can look worse than to see the delicate ebonies and ivories of the notes and drawstops in a state of dirt and dust, helping them, forsooth, to lost their whiteness and polish prematurely. A soft dry duster is all that is needed.”