OUGD404 - Colour 01 - Systematic Colour

The way we see and interpret colour is predetermined by how our eyes receive it. There a three realities of colour, these being:

• The physical colour as created by light.
• The physiological interpretation as seen by the eye.
• The psychological interpretation affected by the mind and pragmatics.

The eyes contain two types of receptors: Rods and Cones.

Rods convey shades of black, white and grey.

Cones, of which there are three types, allow the brain to perceive colour. 

• Cone type 1 is sensitive to red-orange light.
• Cone type 2 is sensitive to green light.
• Cone type 3 is sensitive to blue-violet light.

When a single cone is stimulated, the brain perceives the corresponding colour. When our red-orange cone is stimulated we see red, when our green cone is stimulated we see green. When two or more of our cones a stimulated we see an alternative colour. For example when both out red-orange and green cones are stimulates, we perceive the colour yellow.

It is as a result of this physiological response that we are able to identify the full spectrum of colours, visible through adjustments in the proportions/values of just three colours -  red, green and blue.

The full colour spectrum can also be divided into three sectors, these being primary, secondary and tertiary colours. 

The Primary colours are red, blue and yellow.

The secondary colours are green, orange and purple.

The tertiary colours are yellow-green, yellow-orange, red-orange, red-violet, blue-violet, and 

blue-green.

Analogous colours are those which lie next to each other on the colour wheel.

Contrasting colours, also known as complimentary, are colours opposite each other on the colour wheel. For example, red and green are contrasting colours.

Colour Modes

RGB = Red, Green and Blue. This colour mode is made of additive colour, and should be used when creating work on screen.

CMYK = Cyan, Magenta, Yellow and Key (black). This colour mode is subtractive and should be used when producing work for and in print.


Dimensions of Colour

A Hue refers to one colour, Colour refers to one or several hues though these are often interchangeable terms.

Chroma refers to all colour including shades, tints and tones. The chromatic value of a colour is the hue + tone + saturation.

Saturation is the percentage of pure hue in any colour. For example, pink is a low-saturation of red.

Shades = Hues + Black.

Tints = Hues + White.

Tones = Hues + Grey.