The woad plant (Isatis tinctoria) is widespread across Asia, Europe and America, and has been used for centuries as a paint and a dye, producing a deep indigo colour. Woad seeds have been found in the caves of l'Audoste, Bouches-du-Rhône, France dating from around 10,000 years ago, and the plant was probably introduced to Britain in this Neolithic period. It became widespread throughout Europe and the British Isles in the medieval period, and is mentioned as an important agricultural plant in Irish legal texts (Brehon Laws and Senchas Már) and the Carolingian Capitulare de villis, both dating from the eighth century. There are also archaeological remains of viking dye processing in York. Woad was also the blue dye in well-known medieval textiles, such as the Bayeux Tapestry and The Hunt of the Unicorn.
However, my interest is from a book history point of view, and I wanted to look at evidence for woad in manuscripts, for textual instances but also for physical instances, as a colour. A manuscript from the early twelfth century contains a text called the Gerefa, a late tenth or early eleventh-century agricultural treatise which instructs when to plant woad:
On længtene eregian & impian, beana sawan, wingeard settan, dician, deorhege heawan & raðe æfter ðam, gif hit mot gewiderian, mederan settan, linsed sawan, wadsæd
(In springtime, harrow and graft, sow beans, set out vines, dike deer hedges, hew and directly after that if it might be fair weather set out madder plants, sow linseed, woad seed...)
Bald's Leechbook, a ninth-century medical text that survives in a mid tenth-century manuscript, also has numerous mentions of using woad for various medical ailments, such as pox in the eyes, scabs, wounds, lung disease and burns:
Wiþ bryne wad gecnua wyl on buteran smire mid.
(For a burn grind woad, boil in butter, smear [burn] with [it].)
Woad was probably used as a paint in manuscripts as well. Mark Clarke's article on pigments used in early English manuscripts found several examples of indigotin by using micro-Raman spectroscopy and near-infrared imaging, including the Lindisfarne Gospels and the Royal Bible from the early eighth century. The chemically identical woad (Isatis tinctoria) and indigo (Indigoferra) are known as indigotin, but bearing in mind that woad was indigenous to Britain and that places such as Lincolnshire and Somerset were centres of cultivation, I'm going to assume that woad was the pigment used. Although Europeans were aware of indigo by the thirteenth century, it was prohibitively expensive, and rulers passed laws to forbid the use of indigo to protect the woad agriculture.
So, knowing that woad was present in some medieval manuscripts meant it was worth me experimenting with some! As part of my ongoing book history project to make a manuscript from scratch, I want to make as many natural pigments as I can. As I am generally working in my kitchen or garden, I make sure to choose processes that are known to be safe - so no dangerous chemicals. While this is sensible, it does considerably limit my choices! Anyway, last summer I bought some woad seeds and planted them towards the end of the summer. They overwintered in pots outside, and then I planted them out about April time. I also planted some weld seeds and some madder roots, which will take longer to harvest, but I thought by having a basic colour palette of blue, yellow and red I should be able to then mix a wider range of colours.
By the end of July, the leaves were ready to be harvested. There is no real secrecy around making woad - it is a process so well known that it is well-documented. I followed the steps from the Woad website, which gives clear and easy-to-follow instructions. I won't go through the stages myself, but the images below show the various steps
This was a fun, straight-forward process that took about ten days from cutting the leaves to dried pigment - the only disappointment was the small amount of woad pigment I ended up with. The smell when steeping the woad wasn't too overpowering, the cabbagy reminded me of pak choi (which is not surprising as it part of the Brassica family). I didn't need to buy any special equipment, apart from a meat thermometer to ensure that I cooled the steeping woad down quickly. The most exciting part was filtering the water, which started off a horrible dark green, but gradually turned into clear water, with the blue pigment clearly visible settled at the bottom. Here's a speeded up video of the woad settling after a water change:
From 1kg of woad leaves, I was left with under 1g of woad powder - it didn't even register on the scales! After grinding the powder with a glass muller, it was time to test the colour. I tried mixing with gum arabic and egg glair, and I found that egg glair was the better medium. The paint was a dark, dark blue that at times looked black. I also tried mixing it with white, yellow and red - the yellow in particular produced a pleasing green shade.
Although this is far from the vibrant blue you get from lapis lazuli, it strikes me that as this plant was easy to grow and easy to harvest, it still would have been an acceptable way of creating colour in manuscripts, particularly in England in the early medieval period. I cut these leaves down at the end of July, and within three weeks they had almost replenished themselves, so I will definitely do another batch before the end of the summer. Adding nitrogen to the soil is supposed to create a deeper blue, so I may try that.
Woad would probably have been a staple plant for any medieval garden - it had medicinal uses, and the deep indigo that it released could be used as a dye or paint. The plant is easy to grow and replenishes itself quickly, so would have ensured a ready supply. It's incredibly satisfying to see the whole process through from start to finish - starting the woad off from seed, watching it grow and then harvesting it to produce a useful product. By extracting the pigment I now have a new colour to add to my palette, and I will definitely use it when painting on parchment.
Sara Charles is a 'historical re-maker', recreating medieval manuscript production techniques to understand the practices of the past.
Follow on Twitter @sarajcharles or #medievalstuffwithcats