Hi everybody!

My natural hair color light brown, but with a lot of golden and red highlights. It's nice (and I always go back and forth on just keeping it) but I have always loved dark brown hair. I've colored it before, but when I went from dark dark browon to a cool black I lost my curl completely. Is this because I used a box dye instead of a dye like ion from Sallys?

I guess my questions are : How do you prevent losing your curl when coloring your hair? and Are box dyes more damaging to curly hair than the dyes you would by at beauty supply stores?

Thanks for all your informatioN!