One foil goes in first: a see-through weave at the nape, 20 vol at 1:2 with a bond builder, opened at 10 minutes and at 20. At 10 the strand is still orange, the pigment under a natural 6, and says nothing yet. At 20 it should have moved, and that movement is the whole test. Movement on 20 vol means pale yellow inside 45 to 60 minutes, so the head runs on 20. Still orange means coarse or resistant hair, and those pieces go on 30 vol so it all finishes together.
nobody pulls a strand before a foil job, so the first foil in is doing that job here.
Twenty in the bowl, thirty on the pieces that sat on orange
A natural dark blonde has orange under it, and a foil on 20 vol takes it to a pale-yellow 9 in 45 to 60 minutes, how texture moves those minutes. Mixed 1:2 by the tub, some lines 1:3, a scoop to a scoop and a half at a time, it has to travel through a fine weave and never run out of the foil. Six percent is what most foil work runs on, 30 goes on the pieces the test foil flagged, and 40 stays out. Off the part she wears, see-through weaves for soft and slices for bright, the finest foils back to back at the hairline, and natural hair left out between foils, because the leave-out is the dimension.
Inside the foil the lightener starts just below the fold and never past it. It swells with scalp heat and bleeds a stripe past the edge. Both sides get saturated or a hollow spot comes out as a polka dot. Nobody times a foil. The first one in gets opened, and finished foils come out early with a water bottle and a towel while the back cooks. Forty-five minutes to an hour on 20 vol, watched, is ordinary.
Shampoo, condition, towel-dry, then two bowls. A 6N or 7N tap, 3 to 5 minutes on the root inch, softens the line, then the level 9 toner bowl, a 9.2, or a 9.21 for pearl, on 10 vol or a toning developer, 5 to 20 minutes through the lengths, off before it turns gray. Some skip the tap because the next lift goes through it. Wet hair reads a level darker, so dry it before judging.
Why do highlights go brassy after a few weeks?
Because the toner washes out and the pale yellow the foils lifted to shows through it. The lift itself never fades.
A toner lays on top of the cuticle and a demi holds four to eight weeks, twelve to twenty shampoos. The faint violet of the first dry goes in a shampoo or two, then the cool thins week by week until the foils read as the raw pale yellow they rinsed as.
| Week | What the hair shows | What is leaving | What to do |
|---|---|---|---|
| Day 1 to week 1 | Faint violet, gone in two shampoos | Surface violet | Bond treatment 10 minutes, then judge |
| Weeks 2 to 4 | Still cool, a little less each wash | The demi, outside in | Purple shampoo weekly, it builds slowly |
| Weeks 4 to 8 | Pale yellow through the cool, a soft scalp line | The last of the toner | The two toner bowls again, no lightener |
| Weeks 6 to 10 | Regrowth, hairline foils first | Nothing more | Refoil the regrowth, ends out or on 10 vol |
| Weeks 10 to 12 | Top grown out, underside still passing | Some do the top at 6, the underside at 12 |
How often do highlights on dark blonde hair need a touch up?
Colorists refoil at six to ten weeks; a fine, rooted foil sits at the long end. The four-to-six-week rule, eight at most, is for a whole bleached head, where every scalp strand bands. Foils leave natural hair between them, and that is what buys the weeks: the finer the weave, the softer the line. Paler next time is the same base taken to a 10, another session rather than more minutes.
The retouch, and the band it can leave behind
Lightener goes on the regrowth only; the ends are kicked out of the foil or sit in it on 10 vol with a bond builder. The band on a retouch is made at the top of the foil: lightener laid thick in a straight line leaves a heavy line, and lightener feathered up into a W or a V leaves none. Then the tap and the 9.2 again.
