I was trying to figure what to use to color some pictures/blocks one time. I ended up purchasing several different kinds, then I tested them out on a pre washed piece of fabric and heat set them with an iron (I used brown paper sacks underneath and over the top while pressing). I made a note by each sample of what they were. I tried all colors since I was concerned they would not al,l respond the same(they didn't). And then, I laundered it. Some were good,
some were ok, some didn't take at all.
Try it!