It doesn't sound remarkable except that the Purple Cabbage gives great colours in the pot and then they wash out (cotton) or fade out quickly in light (silk) or hang around for a while (wool) then fade to greige or take only the slightest tint (mohair).
Then there is soy yarn. For some reason Soy loves to be dyed. I am yet to understand why but it is so easy to dye its amazing.
Unfortunately I had only about 20 grams of soy yarn left, so I needed more for a proper test. After months of searching, I found a 70% wool 30% soy yarn. I decided to give it a go hoping the percentage of soy was enough. And yes, it was.
Furthermore the soy enjoyed all the things the wool didn't like such as changing the acidity of the dye bath to make different colours.
So happily I have blue, purple and pink from one dye bath just by adding different things to alter the acidity. I added soda ash to make blue, nothing to make purple (clearly my tapwater is fairly neutral) and a little vinegar to make pink.
The darkest shades were the first dye batch (24 hours) then the paler shades were the second use of the same dye bath (48 hours).
Unfortunately I made the decision to solar dye rather than refrigerate the dye jars. In this nice tropical heat the dye baths fermented and smelt rather like rotten eggs. Not pleasant, but the colours were worth a little nausea!