Natural Dyeing: Red Cabbage

Since I have been back to the city I have been experimenting more with vegetable dyes. I tried red cabbage, because I thought I could achieve blue with it. I read about it in this blog. Mine did not turn out blue but a rosy pink colour. I used pretty much the same dyeing technique as I did with lupine (read about it here). I had a red cabbage that weighed 577 g, I chopped it and boiled it to make the dye. I dyed 25 g of white wool yarn that I had previously mordanted with alum.

The dye turned out very strong purple/red colour, but the finished colour is a rosy pink. At first I was disappointed with this colour but after a day I though it’s quite beautiful and sweet. Although not the kind of colour that I usually go for and definitely not blue. What I think happened is that the cabbage reacted to our tap waters PH. Apparently red cabbage is very sensitive for PH, with acidic it turns pink and with alkaline green. So that would indicate that our water is on an acidic side? I’m terrible at chemistry.  I also put a little bit of vinegar to the rinsing water (so the colour would stay better) but the colour was already pink before that . I have read that red cabbage is a bit risky because it tends to fade away in time. I’m not sure how fast that happens but I’m interested to find out. If any of you have some experiences I would be interested in hearing them.