Grey coverage is one of the most common technical challenges in a salon.
But before we talk about covering grey hair, it helps to understand what “grey” actually is.
Because an individual hair doesn't simply fill up with grey pigment.
Where does natural hair colour come from?
Natural hair colour comes primarily from melanin.
Melanin pigments are produced in association with the hair follicle and incorporated into the growing hair fibre.
Two terms hairdressers should recognise are:
Eumelanin
Associated mainly with brown and black pigmentation.
Pheomelanin
Associated more strongly with yellow and red pigmentation.
The amount and balance of these pigments help create the enormous variation we see in natural hair colour.
This also helps explain why underlying warmth becomes so important when we lighten hair.
So what happens when we go grey?
As hair greys, pigment production associated with the follicle reduces and eventually individual hairs can grow without their previous level of pigmentation.
This produces white or unpigmented hairs.
When those hairs sit amongst darker pigmented hairs, the overall appearance can look grey.
So what we describe as “grey hair” can actually be a mixture of pigmented and non-pigmented hairs.
That becomes important when we formulate colour.
Why do some people go grey earlier?
Genetics plays a major role in when greying begins.
Some people notice their first white hairs relatively young.
Others retain much of their natural pigmentation considerably longer.
There is no universal age when someone is supposed to start going grey.
Why can grey hair feel different?
Clients often tell us their grey hair feels coarser, drier or more difficult to manage.
Not every white hair is inherently coarse, and people's hair naturally changes with age for several reasons.
Changes in density, sebum production, hair diameter, previous chemical treatments and styling habits can all affect how the hair feels.
This is why consultation remains more useful than assuming all grey hair behaves in exactly the same way.
Why is some grey hair resistant to colour?
Ask any colourist and they will tell you:
Not all white hair covers equally.
Some takes colour beautifully.
Some appears to fight you at every appointment.
When we experience resistant coverage, we need to look at the complete colour service.
Consider:
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Percentage of white hair
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Natural depth
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Target depth
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Shade selection
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Amount of natural/base shade included
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Developer
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Saturation
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Section size
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Development time
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Manufacturer instructions
Simply choosing a darker tube doesn't automatically solve poor coverage.
Percentage of white matters
Imagine two clients who both want a level 7 result.
One has approximately 20% white hair.
The other has 90%.
Those are not necessarily the same formulation problem.
The amount of natural pigment already present in the hair influences what we are starting with.
Good colourists formulate for the hair in front of them rather than repeating the same formula on everyone requesting the same shade.
Coverage or blending?
Not every client wants complete opaque grey coverage.
Increasing numbers of clients want softer blending.
They want their white hair incorporated into the overall colour rather than completely hidden.
That changes our approach.
Full coverage and grey blending are different objectives.
Consultation needs to establish which result the client actually wants before formulation begins.
Don't forget application
Sometimes we blame formulation when the problem is application.
Resistant areas need sufficient product.
Fine sections and thorough saturation matter.
Development time matters.
Following the colour manufacturer's instructions matters.
A technically perfect formula applied poorly still gives a poor result.
Grey coverage is chemistry plus technique
Successful grey coverage isn't about memorising one magic formula.
Understand what is missing from the hair.
Assess how much white hair is present.
Know your colour range.
Understand your base shades and reflects.
Choose the appropriate developer.
Apply enough product.
Allow the correct development.
Then adapt according to the individual client.
That is where colour theory becomes useful behind the chair.
Because once you understand why hair behaves the way it does, formulation becomes much less about guessing.