1. Colours of light can be added together to form a variety of colours

2. How the eye sees colour
The eye can only detect three colours of the visible light spectrum:
Red
Blue
Green
These are known as the primary colours of light
These colours then combine to form all other colours

6. Structure of the eye

7. Internal structure of the eye – notice that cone cells are located only at the back of the middle (macula) of the eye
Cones cells detect colour (RBG) while rod cells detect variation of shades of colour

8. Normal colour vision – cone cells help us see in colour

9. This is how a colour blind person sees “colours”

10. Partial function of the cones (red)
Dysfunctions of the rods cells of the eye
Partial function of the cones (red)

11. Additive Primary Colours
Adding green creates two new secondary colours:
Green + Red = Yellow
Green + Blue = Cyan
Magenta is a secondary colour – a mixture of red and blue
Adding all three primary colours recreates white light

12. Combining Primary Additive Colours
The three secondary colours – magenta, yellow and cyan - are also complementary to the primary colour opposite to each.
Red is complementary to Cyan
Blue is complementary to Yellow
Green is complementary to Magenta

13. Combining colours of light – colour equations
Red + Green + Blue = White
R G B = W
Primary colours
Red + Green = Yellow
R G = Y
Secondary colours
Red + Blue = Magenta
R B = M
Green + Blue = Cyan
G B = C

14. Colour blindness tests
Normal – 45
Deficiency - nothing
Normal = nothing
CB - 45
Everyone
Normal – 6
Deficiency - nothing
Normal – 8
R/G = 3
Normal – 29
R/G = 70