I've been playing with mixing dye colours this weekend. I've made lots of swatches with the recipe noted on them so I can achieve the same colours again. I used Procion dye in cyan, yellow, magenta, black, chocolate and lime. Different colours can be achieved with the addition of more water or the addition of another dye colour.
I tried mixing some dye colour into matt and gel acrylic mediums and then printing with them on the Gelli plate. Once the prints were dry I washed a second colour over the top.