Rainbow of plant dyed yarns

As every year, my friend Helene Olli Sollid and I organised a handful of workshops during the Ullveka festival. This year we presented some new plant dyes, including indigo.

Ullveka (Wool week in Norwegian) is a local festival in Nordhordland microregion in south-west Norway. Its main focus is on the local wool production, education, both traditional and contemporary handcrafts and slow fashion.

Rainbow skeins from the nature

The first part of the workshop took place outside, under the grey October sky and still green trees on the pasture of Gripen farm on Holsnøy island. The eight participants and us two took a pleasant walk, collecting plants on the way. We found yarrow, marigold, and hazel (yellows), grey stone lichen (deep orange-brown), old man's beard (orange), and umbilicaria lichen (purple).

After some rest, coffee and tea in the cosy barn we moved into the witch kitchen. Helene has a collection of big pots that come handy a few times a year. Here we went trough some historical facts and some theory in organic chemistry, such as mordanting with alum.

We made 8 colours in total:

• Stone lichen - orange brown
• Marigold + yarrow - bright yellow
• Marigold + yarrow + iron - lime green
• Hazel leaves + iron - dark green
• Yellow onion skins - deep orange-red
• Umbilicaria lichen + salmiac - fuchsia purple
• Old man's beard - yellow-brown
• Coffee - warm beige

All the participants were so fascinated with how bright and clear colours can be obtained natrally. Some dyes (lichens) did not even need mordant to bind to the fibre. It definitely challenges the idea of grey and brown medieval world served to us by film industry, with colours reserved only for royalty. Just look at the bright colours of common people's attires depicted in manuscripts.

Solving the indigo problem

The next day, Sunday, we had only two participants at the workshop, who felt brave enough to master a bit more complicated organic chemistry and try to dye some yarn blue with indigo.

Blue was never exactly easy colour to get. There is a very traditional recipe for ''potty blue'', which uses stale urine, however I don't think the participants would be okay with having to keep their samples outdoors for a few weeks to air out the smell. 

I followed a recipe for an organic vat with fructose (fruit sugar) as a reduction agent. It is a fascinating process, to dissolve the blue powder in a yellow liquid and watch it disappear. It is because indigo is blue only in its oxidized form. However, the oxidized form is not water solluble. That's why we need the reduction agent in the dyeing pot - fructose in this case. And how to make the reduced indigo blue again? The answer is simple: by exposing the dyed wool skein to the oxygen in the air. 

Unlike other dyes which penerate the fibre, indigo deposits in a layer on its surface. That means that it is possible to build up the colour by dipping the developed skein multiple times. It is also possible to overdye yellow to get green, or red to get purple.

All in all, we made it and we all enjoyed this weekend with our pupils. We maybe built some new connections, too.

Photo credit: Helene Olli Sollid