I used to highlight my hair and occasionally color the entire head when I wanted to change the look, and I lost 80% of the curl that way! My hairdresser told me that when you add dye and smooth it through the hair, the chemicals in it are "straightening" it some - which I hadn't even thought of. I have a lot of fine 3a hair, and that was enough to ruin my curls. Since then, I stopped with the color I am back to virgin hair. I guess she was correct because my curls are back better than ever as well! I wonder if it would help to "scrunch" the hair while coloring it so the curl doesn't straighten...
Typical 3a!