This has become my new favorite thing to do. I don't worry about it running because my stuff does not normally get wet. You can heat set it to resist running. Someone also told me that if you dip it in vinegar and then heat it in the microwave for a few minutes, that it would do the same thing. I have not tried that though.
You will need to have color wash and containers margarine tub size or larger for each color, Pearl Ex or Radiant Rain misters or polished pigment powders, natural muslin torn into the size you want, tarp for drying, and a sink. You might want to work near a sink for this technique.
1. Tear the muslin into the sizes you want. Wet the muslin thoroughly. The muslin takes the Color Wash better when wet.
2. Pour the color wash into your container. Add a little water. I use about 2 parts color wash to one part water.
3. Add your pearl ex, Radiant Rain, or Polished Pigments to the color wash in the container. Give it a stir.
4. Fold or twist your muslin in different ways. Then dip areas of your muslin into the color wash until most of it is colored. I go from light to dark. I also sometimes squeeze the muslin to get more color into the middle part. You might want to open up the middle and dip that in. I often have some small white spots. I like that. You will also want to stir up your color wash once in awhile because the pearl ex or radiant rain will sink to the bottom.
5. Take it to the sink and run under cold water. I don't do it until it runs clear. I just do it so the majority of the excess will run off. Wring the muslin.
6. Take the muslin back to the color wash and dip it in random areas into different colors. Wring out over the sink and run the water so your sink won't be stained. DO NOT RINSE THE MUSLIN AGAIN. The reason why I do this is so that parts of my muslin has faded color and some areas have brilliant color.
7. Uncrumple the muslin and lay flat to dry. You might want to turn it over after awhile to make sure the other side dries completely.
8. Once dried, you can spray some more Radiant Rain on for more shimmer. You can iron, if desired.
There are times where I will want to just have one or two colors on my muslin. It looks great if part of it is faded and part of it is not.