This is a guide to colour theory for hairdressing, including where natural hair gets its colour, and what depth and tone are. We also look at how colour theory is used to correct tones and the various factors that can cause hair to change colour. Understanding colour is an essential part of hairdressing – and this post covers all the basics you need to know.
Natural Hair Colour
Our natural hair colour depends on melanin pigments contained within the cortex of the hair.
There are two main melanin pigments found in human hair – eumelanin and pheomelanin. These pigments blend in varying amounts and proportions to form all the hair colours that we see.
- Eumelanin provides black and brown pigments and, therefore, determines how dark hair is. Furthermore, when more of this pigment is present in someone’s hair, it gives the overall hair colour a cool look, like ash. Eumelanin pigments consist of all three primary colours – blue, red and yellow.
- Pheomelanin provides red and yellow pigments. This gives rise to warmer colours in someone’s hair, like auburn, strawberry or gold.
Light blonde hair actually contains relatively little melanin – the pale yellow we see is due to the keratin in the hair, rather than any pigment. White hair contains little or no pigment at all.
- More on colour theory
Why Natural Hair Changes Colour
We can change our hair colour by choice by using hair dyeing products. Here, the various chemical processes in hairdressing (like bleaching, tinting, neutralising) act on the natural pigments to change the hair’s colour.
However, hair colour can change for a variety of other reasons that are not always under our control, including:
- Ageing can affect pigment production. Consequently, as we age, melanin stops being made in our hair and, therefore, individual new hairs can grow without pigment. This is why they are white. When white hair is mixed with hair that still has colour, it creates a grey look – sometimes referred to as “salt and pepper”.
- Blonde children can sometimes see their hair darken when they are around seven or eight years old, and go on to have dark hair in adulthood. The hair darkens as melanin production increases.
- Environmental factors can also impact hair colour. For example, humidity and wind bring more oxygen to hair and this attacks the pigments in the hair. Sunlight can then accelerate the process further. The blue pigments in the hair are the weakest and disappear first. This leaves the warm undertones of red and yellow showing through the hair. Our hair often lightens when on beach holidays due to being exposed more to the combination of sun and wind.
- Health issues can contribute to premature greying. For example, autoimmune thyroid disease, vitiligo, and ageing syndromes can lead to greying hair.
- Medication can alter natural hair colour. For example, certain drugs used to prevent malaria can lighten hair, while some epilepsy drugs can darken it.
- Pregnancy can darken light hair due to higher levels of hormones estrogen and progesterone.
Describing Hair Colour
The hair colour we see consists of depth and tone. Hair also has an undercoat of colour, called undertones, which come into play when we lighten or colour the hair.
Depth or Level
Depth or level simply refers to how light or dark the base colour of the hair is. There are 10 main levels talked about in hairdressing:
- Numbers 1-5 are brown shades – black, darkest brown, dark brown, medium brown, and light brown;
- Number 6-10 are blonde shades – dark blonde, medium blonde, light blonde, very light blonde, and lightest blonde.
- See the chart below for the hair colour numbering. All are classed as neutral shades.
Tone refers to the colours we see in the hair, be they natural colours or artificially added. Tonal colours are classed as warm, neutral or cool:
- Warm tones have reds, yellow and orange in them and are in colours such as strawberry blonde, copper and chestnut brown.
- Neutral tones have a balance of warm and cool pigments in them.
- Cool tones have blues and greens in them and are often referred to as ash tones.
The tonal quality of a hair tint is often given as part of the colour’s description. For example, intense red, honey blonde, rich copper, light beige blonde, and deep chocolate are all descriptions that give us a clue as to what the finished colour will be.
There is also the ICC colouring system, with each tone being given a specific number.
Natural hair has an underlying warm tone, dictated by the amount of the pigment pheomelanin found in the hair. Consequently, undertone can affect the final colour result when dyeing hair.
Dark hair has more pheomelanin present, which creates a red undertone. Blondes have less, resulting in a more yellow undertone.
The undertone becomes more evident when hydrogen peroxide is used to lighten the hair. The undertone also shows through when hair is naturally lightened from exposure to the elements.
Pheomelanin is slowly oxidised during colouring and can produce those difficult-to-remove golden and orange tones in the hair. When dark hair is bleached sufficiently, it will go from having a red tinge to orange, then yellow and, finally, white as the pheomelanin breaks down.
Correcting Unwanted Tones
Correcting tones in hair needs an understanding of colour theory, as well as knowing what products to use and application techniques. The colour wheel is an easy way to see what colours are used to neutralise – simply look at the colour opposite.
To neutralise an unwanted tone, the opposite colour on the colour wheel is used. For example, to remove a gold brassy look from blonde hair, we use a purple shampoo or a mauve ash toner to knock out the unwanted yellow.
If the brassiness is more orange, then a blue-based product would be used. Similarly, if the hair has a green cast to it (sometimes caused by dyeing hair with an ash-based colour), a red-based product is used to neutralise the green.
The colours opposite each other on the colour wheel are also opposite in terms of tone. That is, warm colours neutralise cool colours and vice versa. For example, red (warm) and its opposite colour green (cool) neutralise each other.
Completely neutralising the effect of a tone achieves a neutral shade that is neither warm nor cool.
What Media Hairstylists Should Know
Hair and makeup artists should understand colour theory for hairdressing. We often have to do things like temporarily cover up highlights for a period production. Working on stage or under media lights can affect how hair colour looks.
When we look at hair during a production, the colour we see is influenced by several factors, including:
- The pigments in the hair itself, which absorb some light and reflect others. Natural hair is made up of many colours and absorbs light better than synthetics, which can be very shiny.
- The brightness and colour of the light in which we are looking at the hair. Therefore, the perceived colour of the hair can change depending on the type of lighting and how bright it is.
- Coloured lighting gels can affect how the hair looks on camera or stage.
- To some extent, the costume worn by the person can affect hair colour, as some materials can reflect light.
- The environment or things in it can also have an effect on hair colour.
To summerise, understand how lighting affects colour, and how the materials used for costumes and sets can reflect onto hair and skin. Also, it is good to know how the different hair used in wigs or false hair can look on camera or stage.