Today I tried the recipe from the book Eco-verf, page 196. It’s for extracting pigment from woad but Anja Schrik said it’s the same for indigo.
50 grams of fresh leaves
about 1200 ml boiling water
following the recipe step by step. It is well explained and also has pictures so you know what to look for and why you are asked to do certain things.
Unfortunately it failed. It turned bright yellow when I added the lime/ Calciumhydroxide/ CaHO2. It was supposed to turn into green tea.
I probably added way too much CaHO2 as the recipe made me uncertain at that point by talking about “a cup of CaHO2” instead of grams. I’m also not sure whether I was to add a certain volume in regard to the volume of indigo-tea or in regard to the calcium-hydroxide-solution.
What do you think, did I interpret this correct?
translation p 202:
“The indigo fluid needs to be mixed with a CaHO2 solution. You need 1 part CaHO2 solution for 4 parts indigo fluid. For example: 1 liter indigo fluid requires 250 ml CaHO2 solution.
Prepare the CaHO2 solution: one cup of CaHO2 per 500 ml water. Add the CaHO2 solution to the indigo fluid. It should turn green.”
I had 900 ml indigo fluid so thought I needed just under 250 ml CaHO2 solution. I took 250 ml of water and added “half a cup” which I took to be 2 levelled diner spoons of CaHO2. I don’t know how big the cups of the writer are. It’s not a standard measurement of volume outside of the UK or USA. I was thinking coffee cups (not mugs).
I did a lot of trying to add oxygen but nothing changed, not in the colour, not in the consistency. It smells strongly of cement. When I put it aside there formed a sediment at the bottom (see last picture) and the tell tale “skin” appeared on top of the fluid. But it never got a hint of green or blue.
Now I am blue. I’d really loved this to go right today as I’m having a horrible brain chemistry/PMS day. I have not enough knowledge to know what I did wrong or what I could tweak to make it better. If it’s too much CaHO2 I could perhaps try to make it more acid with some vinegar. But I don’t know. I’m taking a break now. Please let me know if you have advice and I can try some things tomorrow morning.