Colour wheels are based on colour theory, which is based on the physics of light. Without light, no perception of colour is possible, we´d be surrounded by blackness. Light contains a spectrum of colour, from red through to violet, with orange, yellow, green and blue in between, and when all these colours are present in equal amounts we see colour as white.
An object is considered a certain colour by the way it reflects or transmits some of the colour spectrum and absorbs the rest. When any portion of that spectrum is missing, the object containing the remaining portions of the spectrum gives the object a specific colour.
When light is present, the eye can read colour in one of three ways, reflected light, transmitted light, or a combination of reflected
and transmitted light.
1 – Reflected Light
Reflected light is created when light from a light source, reflects off an object. The amount of light reflected depends on the surface area of the object and the brightness of the light source.
2 – Transmitted light
Transmitted light is created when light from a light source, passes through an object. The amount of light transmitted depends on the density of the object and the brightness of the light source.
Colour is made up of Hue, Saturation and Value. By combining these visual properties together we can determine what makes colour.
Colour and hue essentially mean the same thing. It is colour with no Black, White or Grey added. It is the pure form of colour, red is red, green is green, no variations. When we look at the colour wheel we are looking at hues.
The primary colours Red, Yellow and Blue are all hues and it is from these three colours that all other colours are derived. Mixing other colours together can not re-produce primary colours. Children seem to gravitate towards primary colours, check out a children's toy or clothes shop, the colour schemes usually contain predominately primary colours.
I read somewhere it has to do with their eyes, not being fully developed and primary colours being the first colours they can interpret, has sense I suppose.
When we mix two primary colours together we get what is called a secondary colour.
These secondary colours are, Green, Orange and Purple so when we mix the primary colours red and yellow we get the secondary colour Orange, likewise, when we mix the primary colours yellow and blue we get the secondary colour green. When we mix Secondary colours together we get what are called Tertiary colours, the six tertiary colours are: Red-orange, yellow-orange, red-violet, blue-violet, blue-green and yellow-green.
The intensity or purity of a colour is called Saturation. Adding or subtracting grey determines the saturation of a colour. The greyer a colour is, the less its saturation. A colour completely absent of grey is fully saturated.
The primary colours are considered fully saturated. If colours appear dark, they are over saturated while colours that appear washed out or faded are said to be under saturated.
The lightness or darkness of a colour is called its value. Simply put, it is how much white or black is contained within the colour. Adding white to a colour is known as tinting while adding black to a colour is known as shading.
Toning a colour means adding either white or black. Mid tones are the medium values between black and white.
How a colour is perceived is influenced greatly by its value or saturation.
Additive and subtractive colours
There are two common types of colour referred to as additive and subtractive colours. Red, Green and Blue (RGB) are considered to be additive colours, you add them together to produce white. RGB values is how a computer or TV thinks about colour.
While Cyan, Magenta and yellow are considered to be Subtractive colours, you subtract them to get white. These colours are usually made up of ink or paint and they produce colour by subtracting white. The offset print process that involves CMYK works along this principle.
So lets say, we subtract the additive primary colour red from white, and we are left with the primary additive colours blue and green, combining these two colours gives us the subtractive colour cyan. In essence, a subtractive colour is a mix of the two additive primary colours when one additive primary colour has been removed from white.
Print colour and Monitor colour
Colour combinations will either make or break a design. Overloading a design with to much colour can be uncomfortable and off putting while using to little colour can be dull and boring. Like everything in design its about balance.
The use of a single neutral colour describes a monotone achromatic scheme. It consists of colours ranging only from black to white.
The use a single colour from the colour wheel and the different tints, shadows and saturation of that particular colour. A colour scheme like this can unify a design because all elements work in harmony together sharing different variations of the same colour but on the down side, it sometimes can be dull and monotonous.
Analogous colours are neighbouring colours on the colour wheel, for example Red, Red-Orange and Orange. That particular group can communicate a warm, cozy feeling in a design while Blue, Blue-Green and Green can communicate a cold, icy feeling. In a design cool colours can appear farther away while warm colours can appear closer.
Complementary colours are total opposites of each other on the colour wheel. They compliment each other and as a result work well together. Blue is complementary colour for orange. Purple is complementary colour of yellow. Placed together they grab attention and seem to energise and contrast each other. The act to balance each other, one is always warm and the other always cold. Red placed with Green seems even redder, as with blue placed with orange or yellow placed with purple.