FEASA LED ANALYSER
ICT VERSION
Colour and Saturation
Figure 1: Hue (colour) Wheel
RED
=
0º
GREEN
=
120º
BLUE
=
240º
Colours can represented by a 360° degree circular Colour wheel. The three Primary RGB values
can also be represented as a single value called
Hue
.
Hue is a measured location on a Colour wheel and is expressed in degrees.
For example, Red will have a Hue value near 0°, Green will have a Hue value near 120° and
Blue will have a value near 240°.
A pure Colour will be represented on the Colour wheel as a point near the outer edge. White
will be represented by a point near the center of the wheel. The degree of whiteness in a LED
will affect its position on the wheel – the greater the amount of white the closer it will be to the
center.
The degree of whiteness emitted by the LED is represented by the term
Saturation
. A
Saturation value of 0% represents pure White. A Saturation value of 100% represents a pure
Colour such as Red, Blue, Green, etc.
Usually the user must determine the Hue and Saturation values by testing a number of LED's
and recording the results.
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