I tried to dye a cheap cotton t-shirt with turmeric yesterday and the strangest thing happened. It's probably perfectly normal and has an explanation, but I hadn't done any research beforehand.
I dyed it on the stovetop in a huge pot for about 30 minutes, and each time I stirred it it looked like a dark celery color. When I started rinsing it I realized that it was turning darker where the water was running on it. It eventually went from the medium dirty yellow it had been to a dark burnt orange (the color was uniform by the time I finished rinsing it, or rather gave up rinsing it--after many rinses the water still wasn't running clear, so I figured I would wash it later in the machine).
I rung it out and rolled it up in a towel to blot it dry, then hung it on a hanger, and at this point I noticed that there were some bright mustard yellow spots on the burnt orange in places where the towel had rubbed it, and in places where I'd had to handle it to put it on the hanger (also where care instructions were printed on the inside). I started touching it with varying pressure and realized that where I touched it it was turning yellow--the spots were more pronounced where I touched it longer or put more pressure. I thought maybe it would even out after it dried, but the spots were just as pronounced this morning.
Is there an explanation for this? It was a fun experiment, but I still have no idea what caused it or how to get an even dye job with turmeric on cotton fabric. Is it because I didn't rinse it with vinegar? Does this happen when dyeing yarn, too?