When I bought the yarn for this, I was thinking white cotton. Suddenly at the check out counter, I realised that the pattern weft will be better as a contrast colour so that I can see it! I bought a pale yellow so that when it is over-dyed, I may be able to keep it if I can undo it in one continuous length. I have been saving the yarn from other shibori pieces for a future project.
This is very exciting and I am looking forward to the next shibori group get together!