The source of colour 2

Level 2 Diploma in Painting and Decorating
© 2013 City and Guilds of London Institute. All rights reserved.
The source of colour
Unit 230: Creating and applying colour

Introduction
• Have you ever wondered what colour actually is?
• You may wonder why it is important to know. The answer is
because it is the beginning of a fascinating journey on how colour
influences our daily lives and should never be taken for granted.
• The following set of slides will explain where colour comes from and
how it is actually seen.

Where does colour come from?
Colour comes from light – white light to be exact. There are two sources
of what we perceive as light:
•Artificial light: street lights, torches, household bulbs etc
•Natural light: daylight/sunlight
Colour comes from natural sunlight, which is commonly known as white
light. The following slides explain how white light becomes colour.

You have probably heard of the term speed of light. How fast do you
think it is?
•The speed of sound is 300 metres per second.
•The speed of light is 300,000km/s which is 1 million times faster
That is roughly the equivalent of flying around the world nearly eight
times every second!
The speed of light

The colour spectrum
In order to be able to see colour, white light speed needs to be slowed
down. This can be done by transmitting it through a prism, which will
then reveal what is known as the colour spectrum.
GREENGREEN
INDIGOINDIGO
YELLOWYELLOW
BLUEBLUE
REDRED
ORANGEORANGE
VIOLETVIOLET
White
light

Seeing colour – wavelengths
• Now you know what colour is and where it comes from, how do you
actually see it?
• Colour travels in wavelengths in the white light. Although these
colours travel at the same speed, they are different wavelengths
and frequencies.
• Red is low frequency (long wavelength); blue is high frequency
(short wavelength).

What are wavelengths and frequencies?
To explain these terms, think about picking up and flicking a long piece
of rope – the slower you do it, the longer and less frequent the curves
or ripples will be (low frequency/long waves).
Using more force and flicking it harder will result in shorter ripples
arriving more frequently (high frequency/short waves). Radio waves
and microwaves are delivered in the same way.

Warm and cool colour frequencies
Frequencies are directly related to colour.
• Cool colours are made up of high frequency wavelengths.
• Warm colours are made up of low frequency wavelengths.
230.6

Seeing colour
• As the light lands on a surface, all the other coloured wavelengths
are absorbed into it except those that correspond to the actual
properties of the surface itself.
• These are then reflected at different wavelengths to an area of the
brain that interprets them as different colours.
• For instance, sunlight landing on a red surface:
230.7

Invisible colours
• Strange as it may sound, there are also colours that are invisible to
the human eye in natural light. They can be found beyond either end
of the colour spectrum.
• These cannot be seen* because the human brain is not able to
process the frequency of their wavelengths.
• These two colours are infrared and ultraviolet.
* Unless you are a bee – they can actually see ultraviolet!!

Any questions?

The source of colour 2

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