Colours plays many roles in our lives: colours give us information about our environment; keep us safe by signalling danger; help us decide whether food is safe to eat; and help us navigate. Colours also bring us joy as we watch a beautiful sunset. Noticing, describing and understanding the key roles that colour plays in our lives helps us establish a strong relationship with our surroundings, and deeply engage in the world.

Colours can impact us in many ways. They affect us viscerally, impacting how we feel in ways we cannot fully describe with words. We may have strong responses to colours, have various colour preferences, have strong or weak emotional responses to colours, and have various associations with colours influenced by our culture, language, memories and past experiences. Our human relationship with colour is complex, and there is no ‘one-size-fits-all’ connection between specific colours and specific responses, which applies universally to all people, across all cultures.

Often, colours are described by using just their hue name - red, blue, green, etc. However, they can be better described by both their hue family and their their character - i.e. whether they are vivid (vibrant/bright), pale (pastel/light), dark (deep), or muted (muddy/dull). By describing colours with modifiers at the earliest stages of colour education, students enhance both their perceptual colour discrimination and their verbal descriptive capabilities.

Basic 3D models which represent colours show colour relationships in three spatial directions or dimensions:

1. Colours related by hue (e.g. the hue circle)

2. Colours related by lightness (e.g. comparing the light reflected by the colour to a grey scale between black and white)

3. Colours related by chroma (e.g. the amount of visual distance from the grey scale member of equal lightness)

By organizing colours in 3D colour models at an early stage of colour education, rather than beginning with the visually limited 2D hue circle, students better grasp the myriad of colour variations and their relationships, and become more confident in their work with coloured media.

Although it seems as if colour is a property of the physical world that is ‘out there’, colour is ultimately a perception which results when light enters our eyes and activates our whole visual system.

What colours are, whether they are properties of substances or light, manifestations of radiant energy, pure subjective experiences, or results of interactions between the perceiving subject and any of the above is a matter of ongoing scientific and philosophical debate. In any account it must be recognised that colours are, ultimately, a visual phenomenon.

There are many variations in the way we perceive colours. Some people have limited colour vision, and see only a fraction of colours seen by people with full colour vision. Other people with synesthesia can experience colours when other senses are activated.

When light activates our visual system, we experience a colour perception. Light can come to us directly, from sources like the Sun or a computer screen), or indirectly, after it has interacted with some kind of object (like an apple or a splotch of paint). The illumination conditions vary both in intensity and in spectral composition, and will influence the perceived colours of illuminated objects in our environment.

Coloured areas are never viewed in isolation. Rather, they are viewed within complex scenes.. Both the lighting conditions and the surrounding colours will influence how we perceive the colours of objects in our environment. Colour perception is highly contextual.

In addition to the various external contexts which impact the colours we see, there are several internal contexts which also can play a role in how we perceive colour. Our memories, experiences, culture and language all contribute to the overall context for colour perception.

Colour is a non-verbal perceptual experience, and can signal things like danger or various types of social behaviours in the natural world. Humans have many cultural associations with colours, which are often thought to have universal symbolic meanings, however colour symbolism and meaning are complex ideas, intertwined with history, nature, culture and context. Such associations often simply connect the hue of a colour with a particular emotion or idea. However, associations linking the character of the colour. (e.g. whether it is vivid, pale, dark and muted) with an emotion or idea may more strongly convey the connection.

Colour is often used by artists and designers to represent emotions and/or enhance the messaging of a particular idea or concept.

It is important to recognize that we do not mix colours, rather we mix coloured media. Colours are perceptual experiences, and can’t be mixed, but colorants or coloured media can.

There are many mixing processes including:

• Additive mixing of coloured light sources

• Optical mixing on display screens (e.g. computer or phone)

• Subtractive mixing of paints, inks, dyes, etc.

• Optical mixing using spinning disks (via temporal averaging), or Pointillist painting (also called partitive mixing)

In each type of mixing process, the media interact with light in slightly different ways. This means that the light which is sent to our eye depends both on the mixing process and on the specific medium used. Thus the perceived colour of a mixture depends both on the process and the medium.