A brassy 7 that wants to be a clean light blonde is either a one-visit head or a two-visit head, and the job is telling which before you mix. The bowl on the card above is the one-visit route. Read the rest before you trust it.
Which head is in the chair
Healthy, even, never lightened or lightened once and evenly: one visit. A permanent 8.1 on 20 vol cools the yellow-orange and moves the hair a half level, and she leaves a cool 7.5 to 8. Anything with bands, old highlights, box color in the lengths or ends that feel like straw: two visits. That bowl cools what it can and lifts nothing; the true 8 is bleach, a rest, and the level 8 to 8 formula a fortnight later.
| What the dry hair shows | Which case | One bowl of 8.1 on 20 vol gives | The plan |
|---|---|---|---|
| Yellow-orange root to tip, never colored | One visit | A cool 7.5 to 8 | This formula, done |
| Yellow-orange, one old permanent, no bands | One visit, probably | Cool 7.5, lift uncertain | Strand test first |
| Yellow-orange roots, orange ends | Two visits | Cool roots at 8, ends barely touched | Bleach the ends to match, then demi 8.1 |
| Old highlights, three tones in the lengths | Two visits | A stripy, muddy cool 7 | Bleach through, rest, demi 8.1 |
| Bleached before, rough ends | Two visits, maybe none | Ends grab ash, go gray, no lift | Demi 8.1 cut with clear; lift later |
In my chair the one-visit head is the exception; I think most 7s that come in wanting light blonde are two-visit heads, so the honest consult says so before the gown goes on.
What even means
Even means the same pigment showing at the root, the mids and the ends, on dry hair, at a window. Yellow-orange everywhere is even. I part the dry hair in four places with the tail comb and photograph each parting on my phone with the flash off; the phone catches a band my eye skips. Once I did the one-visit route on a head I had parted at the front only. The crown was a good 7 and the nape an old 6 from a box (nobody mentions the box color from two years ago until the strand comes back green), and she left with a cool 8 on top and a warm 6.5 underneath. That one cost me a free visit and a bowl of bleach.
Why an 8.1 on 20 vol
The pigment under a 7 is yellow-orange, and blue-violet cancels it. An 8.1 carries blue for the orange half; 8.12 adds violet for the yellow half, and a third of the bowl goes to it when the swatch shows more yellow than orange. The 8 in the code is where the hair is heading, and the 20 vol gets it there, a half level in the 30 minutes the ash needs to cool. On 30 vol the orange lifts faster than the ash can cover it and you rinse warm.
The one-visit route on the clock
Dry hair, mid-lengths first, then roots, ends last. At 10 the yellow-orange looks brighter; at 15 it has gone to a dull straw and the roots are ahead. At 25 the mids read cool and a step lighter, and 30 is the rinse. But give it 35 if the hair is coarse and slow. After 35 the ash keeps depositing on hair that has stopped lifting and you rinse a gray 7.5. The processing time calculator adjusts for texture. What I cannot tell you is how far the 20 vol will move a given 7; fine hair may go a full level and coarse hair sit at 7.5, and the strand is my only forecast.
Porous ends
Ends that have seen lightener drink the 8.1 in four or five minutes and go ashy-gray before the roots have cooled. Keep a second bowl of the formula cut 1:1 with clear for them, applied last. Ends that feel rough when dry get no 20 vol at all; a demi 8.1 tones them and the lift waits.
What fades and what stays
The blue goes first, at four to five weeks, and the hair drifts back to a warm 7.5. The half level of lift stays. A purple shampoo once a week holds the ash a fortnight longer. Fresh yellow-orange at the root by week six is a level 8 toning job from then on, a demi rather than more 20 vol, and the toner selector picks the code.
