What if I were to mix the dyes?

I'm in the mood to do a bit of experimenting with my hair colour. I normally dye it a light blonde, not white by any means, which looks rather natural with my very white colouring. I think I want it to be more white with a pink hue, though. If I were to mix a bit of lighter hair dye with some pink/purple dye I bought a while ago(nothing fancy- just Color Jamz. Raspberry Kamikaze) would this achieve this? Or should I just spring to get it done professionally?