The advantage of the International Feltmakers Association’s regional groups is that they all organise their own workshops and activities to bring local felters together. But members of other groups are equally welcome if they are willing to travel.
So it was that I found myself heading for Ipswich a couple of weekends ago to attend a workshop on plant dyeing for felters, organised by Sally Sparrow of region 7. My god daughter lives in Manningtree, not far from Ipswich, and was willing to put me up for the weekend as well as drive me back and forth.
The workshop was run by Susan Dye (how’s that for nominative determinism?) of Nature’s Rainbow, ably assisted by her partner Ashley Walker and weaver and knitter Brian Bond. As inspiration, they brought along samples of yarns, fabrics and fleece, plus knitted and woven pieces in a whole spectrum of strong, bright colours.
Susan and Ashley grow their own dye plants on their allotment in Hitchin, specialising in grand teint – the medieval dyer’s guild term for the most light-fast and wash-fast colours. These include dyer’s weld (yellow), woad (blue) and madder (red).
As well as these, they also brought along other plants they had grown – dyer’s chamomile (yellow) and dyer’s coreopsis (yellowy orange) – for us to play with.
Although I have dabbled with natural dyes, it’s been mostly on silk, so I wanted to get some tips on the tricky problem of dyeing wool without felting. However, I learnt so much more that can be applied to all natural dyeing , whatever the fabric or fibre.
Susan provided a very comprehensive handout on mordanting, including lots of safety information. There was lots of useful detail here – for example:
- Dyer’s cream of tartar, often used with alum to help it dissolve, is different from baking cream of tartar, which has additives like anti-caking agents. If you can’t get dyer’s cream of tartar, it’s better not to use any at all.
- Soak silk for at least 24 hours before mordanting – it is very resistant to wetting out.
- After mordanting in alum, do not rinse the items immediately but store them damp for about a week. This is called ripening and really helps the mordanting. Then rinse thoroughly in cold water before use.
A hay box is a non-electric version of a slow cooker, where you bring the food to the boil initially on a stove and then put it in a box insulated with hay, which preserves the heat and allows it to carry on cooking. It was a cooking method encouraged during the Second World War to save on rationed cooking fuel.
For dyeing, when you have to bring a pot of dye up to a certain temperature and then keep it there for an hour or so, a hay box can help save energy as well as on heating appliances.
There are various sites that explain how to build one, but Susan and Ashley have improvised with cardboard boxes and old cool bags, lining them with old blankets, duvets, fleece jackets and the like. It’s particularly important to insulate the top of the dye pot, as this is where most of the heat escapes.
We started with the yellows, setting up baths of dyer’s weld, dyer’s chamomile and dyer’s coreopsis. Chamomile and coreopsis give different shades of yellow, but they are less light fast than weld, so anything dyed with them should be kept out of the sun.
We poured boiling water onto the plants and then put the pots in hay boxes for an hour. Because only the chamomile and coreopsis flower heads are used for the clearest, brightest colours when dyeing, they also release their colour more quickly than weld, where the whole plant is chopped up. Then we strained out the plant material (using old tights!), and let the bath cool.
The alum-mordanted wool (mostly organic merino from the Falklands) had already been separated into 50g hanks and wetted out well, so we put 50g in each dye pot and reheated to 70°C.
To get clearer, brighter colours from weld it needs to be kept below 70°C – at higher temperatures you get more of a straw colour. Then it was back in the hay box, gently flipping the wool once to minimise felting, until we were happy with the colour.
This was the basic method used throughout, with wool and silk repeatedly added to the dye baths until they were exhausted. Susan had brought along record cards to note the type of fibre, temperatures, times, and mordants, and was very insistent that the card stayed with each sample so that we knew exactly how each one had been treated.
After cooling and rinsing, the wool was hung up to dry – we soon had a fine range of yellows!
Indigo and woad
In the afternoon the blues were introduced, with Ashley making up three baths: one from natural indigo stock solution, one from woad stock solution and one from woad powder. At home Ashley creates an indigo bath from leaves grown in his dye garden. The plants are harvested before they flower and the leaves are stripped off.
In the case of Japanese indigo, the leaves are put in cold water and slowly heated to 90C. Then they are left for an hour to cool to around 60C – the liquid is a greyish tan colour. After removing the leaves, alkali is added and the liquid is oxygenated by whisking or decanting it between containers. Once it has turned green it can be stored indefinitely in this form. (For woad, boiling water is poured onto the leaves instead of putting them in cold water and heating.)
To make the dye bath we added the reducing agent and checked the pH (for wool pH 8-9 is best).
The woad bath was rather weak – it turned out that the stock solution had been over reduced because the woad powder contained much less indigo than estimated.
However, overdyeing some of the yellow wool with the weak woad gave a fantastic lime green colour that was almost fluorescent!
Ashley explained that to get good greens the indigo or woad bath mustn’t be too strong, or the blue will overwhelm the yellow.
Coming soon in part 2 – We complete the rainbow with madder.