When you've got someone like Amber here, with longish hair that's already got some highlights in it, and she wants to be hot pink all over, guess what? You are foiling every hair on that head (a.k.a., "platinum carding"). When bleaching hair that is more than a few inches long, you start losing control of the process if you just slap bleach on like you would color; your roots will come out very light while your ends are likely to be stuck in the orange stage. With foils, you get a much more even lift because they help control the heat distribution and they keep the bleach wet.
So, I start in the back on the bottom with a lower volume developer, I work upward and forward, and I gradually increase the strength of the developer (called "bumping" the developer) as I go along. This is to keep the processing time a bit more even, but also, getting that many foils in by myself takes a long time, so if the back gets done processing before the front, it's easy to rinse out if I need to. So that's what we did on Amber. The highlighted pieces only got bleached on the regrowth, and the rest got foiled all to hell. Then we rinsed (shampoo only), and I used Special Effects Atomic Pink on the majority of her hair. Four foils in the front: two each of pravana violet and SFX electric blue. Rinse with cold water, conditioner only. The end.
Thanks for reading, and post any questions below!