PHYSICS: COLOURS OF LIGHT

Colours of Light

The Component of White Light

Explain the component of white light

There are two types of colour of light

1. Primary colour of light
2. Secondary colour of light

Primary colour of light

These are basic (fundamental ) Colour of light to which the eye is most sensitive.Primary Colour of light Include the following

1. Red
2. Green
3. Blue

Secondary colours of light

These are colour of light obtained after mixing primary colours of light

Colour mixing by Addition

This is the process of combining primary colours of light without loss any colour to form secondary colours of light.

	Primary color	Secondary color
	Red + Blue	Magenta
	Red + Green	Yellow
	Blue + Green	Cyan

Colours of White Light

Recombine colours of white light

When all white light ( Red , Blue and Green)Combineforms WHITE LIGHT.

Complementary colours of light: These are the colours which produce white light when combined.

• Red + Blue+ Green - White light
• Red + Cyan - White light
• Blue + Yellow - White light
• Green + Magenta - White light

The Appearances of Coloured Object under White Light

Explain the appearances of coloured object under white light

There are two types of coloured paints ( pigments) which Include the following

1. Primary coloured pigment (paints)
2. Secondary coloured pigment (paints)

Primary, Secondary and Complementary Colours of Light

Identify primary, secondary and complementary colours of light

Primary Coloured pigments

These are basic coloured pigments which form secondary coloured pigment when combined.

The primary coloured pigments include:Yellow, Cyan and Magenta

Secondary colour pigments

These are coloured pigments which are formed when two primary colours combine, whichis always accompanied with the removal of other colours.

Difference between Additive and Subtractive Combination of Colours

Distinguish between additive and subtractive combination of colours

Colour Mixing by Substration

Is the process of mixing two primary coloured paints ( pigments) to form secondary colour white.

Example 3

• Magenta + Cyan
• Magenta = ( Blue) + ( Red)
• Cyan = (Blue) + (green)

The colour which is common to Blue will appear while red and green disappear.

Magenta + Cyan = Blue

Example 4

• Magenta + yellow
• Magenta = (Blue) + (Red)
• Yellow = (Green) + (Red)

The colour which is common to both red will appear while blue and green will disappear.

Hence

Magenta + Yellow = Red

Example 5

• Cyan + yellow
• Cyan = (Blue) + (Green)
• Yellow = (Red) + (Green)

The colour which is common to both green will appearwhile Blue and Red will disappear

Hence

Cyan + Yellow = Green