What is human hue?
Hue is the term we use to describe the colour category of the pigment which is biologically present in human colour characteristics.

Human natural selection ensures that when two people procreate, their natural colour pigmentation creates a colour combination of skin, hair and eyes which balance and harmonise.
The resulting colour combination may be different to the parents.

The underlying hue quality in most people’s skin, hair and eyes are recessive (unable to be perceived by the human eye). The underlying hue of a person’s pigmentation is known in the colorDNA system as the foundation colour.

It is difficult to determine the underlying hue quality of most people’s colour characteristics, given the hue is masked by a neutral colour tone.
Red hair and light-coloured eyes are a couple of general exceptions.

Each neutral colour characteristic has a natural foundation hue – and usually only one – even if the tone of the skin is substantially lighter than the hair and eyes.

Most people have the same biological hue category across their skin, hair and eyes (considering most Asian and African people have the same hue category across their skin, hair and eyes).

However, from the various cool northern climates of the globe, people evolved with a range of different coloured eyes and hair.
Furthermore, global migration has created widespread genetic diversity, and innumerable mixed-race people with unique colour characteristic combinations.

In our research we classified 11 different human eye hues. Some of the hue categories were recessive, such as red and red orange, masked by the brown neutral tones.
The only colour category from the colour wheel we did not find present in human eyes was red violet.

I’m sure there is someone in the world with the rare red violet eye hue.
In fact, we only found one person with violet-coloured eyes, and that person had albinism.
The cool northern climates and unique colour characteristic combinations from mixed-race heritage have also produced a wider range of neutral-coloured human hair.

Within natural-coloured human hair tones, the foundation hue of some people from northern European climates with blond/e hair is yellow. We did not find human skin pigmentation with an underlying yellow hue.
In our hair hue research, we found there are five natural foundation hair hue categories – red, red orange, orange, yellow orange and yellow.

Exceptional hue differences within the skin are most often due to health, illness, a genetic condition or aging.
When more than one hue category occurs, one is likely to dominate.

Multicoloured eyes and hair are not unusual within Caucasian people.

The chance of multicoloured eyes and hair occurring increases when different races of people combine their DNA.

This applies from the lightest of albino colour combinations to the darkest brown pigment combinations.

Contrasting high and low light hue categories do exist between individual colour characteristics on some people.
Contrasting hue qualities between colour characteristics include different coloured eyes, hair, lips and rosy cheeks.

As a rule, hue categories remain the same throughout a person’s life.
However, as people age, the intensity of their pigmentation weakens and pigmentation production stops.
Loss of pigmentation causes the hair to turn grey or white – then the hair has no hue category.

Aging also causes the discolouring to the whites of the eyes and teeth.

It is rare for the colour of human eyes to change, but it can happen. If it does, it’s usually during adolescence.
Changes in eye colour can also be linked to injury, infection or sun damage.
Illness, inflammation and skin conditions such as rosacea can also produce changes to a person’s skin hue, usually elevating a person’s red hue category.

Superficial and enhanced changes, such as hair colouring, coloured contact lenses and make-up, will also affect a person’s colour expression.

Changing the colour of a person’s hair, eyes and skin – through dye, headwear, make-up, face paint or tattoos – is a massive topic, for another one or 10 articles.
