I dyed a t-shirt for bob using low-water immersion after tying it in little bunches with water-soluble thread. The idea of using the water-soluble thread was to avoid white marks — I wanted it to just be “different” in some way in the tied parts, but not to block the dye completely. (Also I didn’t want to have to untie it all afterwards.)
The low-water immersion worked nicely to split out the constituent red (magenta) and blue (cobalt blue) parts of the dye, giving lots of different purples, and the little tied bunches ended up looking like cells or neurons (according to bob).
Photos here of the tied t-shirt before going in the dye bath, plus a close-up and not-close-up of the results. bob has a photo of him wearing it which no doubt he will post in this thread at some point.