Need Help from Tie-Dye Pros

[daemom]

Have any of you tie dyed anything that wasn't white? DS teacher wanted me to tie dye shirts for the class--I've only used white shirts in my experience. For field day each grade wears a special colored shirt for easy identification. this year someone got t-shirts for $1.50 each for the whole school (parents paid) and our group shirt is blue--I'm hoping light blue., and it's possible that it will be a medium blue. Do you think a blue shirt would take dye okay? I was thinking using a dark blue dye, but the teacher really wants to add pastels. Do any of you think that either of these could be done? What colors?

Thanks for any help and ideas!