What happens on the head
Hair grows roughly a centimetre a month, and that centimetre arrives in your natural depth, grey included. Root colouring puts pigment on that regrowth only: colour is painted in fine sections along the parting, hairline and crown, left to develop, then rinsed. During development the colour lifts the outer layer of the new hair, deposits pigment inside it, and settles it back down, so the fresh growth sits at the same depth as the hair below it.
How a roots touch up differs from colouring the whole head
Full head colour re-pigments everything from scalp to ends. A roots touch up stops at the demarcation line, usually the first two to four centimetres, and feathers into what is already there. Less product touches the hair, development time is shorter, and the lengths you have spent a year growing stay untouched. That last point does most of the work for anyone carrying balayage, where the value sits entirely in ends that have never been flooded with base colour.
Darkening the roots
Roots that were lightened in a previous colour, or that have gone lighter than the rest through repeated bleaching at the scalp, get the reverse treatment. Pigment is built back into the regrowth in stages so the new depth holds instead of washing out grey after two shampoos. Hair colour at the roots that has lifted too far usually needs a filler shade first, then the target depth on top.
Who books hair root touch up at salon
- Grey at the temples or the parting showing three to four weeks after a colour
- A dark band across the crown after a holiday or a long gap between appointments
- Dark natural hair pushing through a lighter shade, or a light root under a darker one
- Anyone stretching to eight weeks between full colours who needs the line gone in the meantime
- Roots that have gone brassy or ashy against the lengths and need resetting to one depth
Results and how long they hold
The result is there the moment the colour is rinsed, with no build-up over several visits. Full grey coverage holds four to six weeks before the next centimetre becomes visible. Where the ends have dulled or warmed up in the meantime, a gloss run through the lengths at the same appointment brings both halves back to one tone.
Session lengths
A 45 minute slot covers shade matching, application, development and a rinse. A 60 minute slot adds a finish and a blow dry. A 90 minute slot is for regrowth plus a refresh through the lengths, and it is the one to book when the ends have shifted as much as the roots have.
Keeping to a cycle
Four to six weeks suits full grey coverage. Six to eight works for softer shades close to your natural depth, where the line comes through gently. Hair coloured on a regular cycle takes pigment far more evenly than hair left to grow out and then rescued, and a K18 hair treatment at every second visit keeps the regrowth strong through repeated colour.
