I used tea to dye some cotton muslin (to use as a base for some nuno felt) and it looked wonderful... So I spent hours making the felt, especially chosing colours that worked with the fabric - all went well until I immersed the fabric in hot water and all the colour ran out
. I've checked these boards and the suggestion is that I shouldn't need to fix a tannin-based dye? Anyone any ideas what went wrong?