Q: How do you prevent dark bands?

A: "I always suggest being very careful not to overlap," says Wella Top Artist Alexandra Matiz. "Also, add some gold into the formula to prevent dark bands. Since the single process is the service most likely to need these bands fixed, I love to paint overthe band with Wella Koleston Perfect Special Mix 0/33 with 30- or 40-volume developer; it works like magic."

How do I prevent dark bands? How do I prevent dark bands?