Colour correction after home dye: what can be fixed, and what cannot
Correcting home colour is one of the most common and longest jobs in the salon. Not because anyone made a mistake, but because box dye works with a single mixture across the whole head — whereas in the salon the root, the lengths and the ends are each judged separately.
Why does it go patchy?
The hair shaft is not the same along its whole length. At the root it is new and intact, and the warmth of the scalp speeds the colour up. Halfway down there may be layers of earlier colour. The ends are porous and soak up colour like a sponge.
One mixture therefore gives three different results: a lighter root, a mid-tone length, and dark or ashy ends. That is the classic patchy effect.
What is possible in one session?
If the aim is an even colour and you do not want to go much lighter, a full colour change with evening-out is often enough. Here that runs around five hours, with two hundred and thirty grams of product — a quantity that on its own shows why it is not comparable to a straightforward colour.
If you want to go from dark to light, though, one session will not do it. The dark, deposited pigment has to be lifted out of the shaft, and that takes several steps, with treatments in between and weeks of pause.
What cannot be fixed straight away
Hair that is broken and feels rubbery is not saved by colour. If home dye or bleach went too far, the next step is not another chemical process but treatment and a cut.
That is the hardest sentence in a consultation, and the most important one: sometimes the right answer is that we are not colouring today.
What to bring to the consultation
- The box, or at least its name and shade number.
- When and how many times you have coloured in the past year.
- A picture of where you would like to get to.
The first two are technical questions, and they are worth more than you would think: the earlier layers on the shaft decide what is possible.
And thinking ahead
If you are planning your next colour in a salon, do not dye at home beforehand just to hide the regrowth in the meantime. A grown-out root is a far easier job than a freshly added layer of unknown composition.