Colour Perception Flashcards
(17 cards)
What are the functions of colour perception for humans?
To find food
To determine poisonous animals
To attract a mate
How is the colour of an opaque object determined?
The colour of an opaque object is determined by the light that it reflects.
How is the colour of a transparent object determined?
The colour of a transparent object is determined by the light it transmits.
What happens if you mix red and green light?
You get yellow light. Think about traffic lights to help remember.
What are rods?
Photoreceptors that cannot distinguish between colours and are only active in low-light conditions.
What colour wavelength do S cones respond to?
Blue
What colour wavelength do M cones respond to?
Green
What colour wavelength do L cones respond to?
Red
What is monochromatism?
A condition where affected individuals have no functioning cones and only see the world in shades of grey. Affects 1 in 100,000.
What is dichromatism?
A condition where affected individuals are lacking one of the three types of cones.
What type of cone does a person with Protanopia lack?
L (red)
What type of cone does a person with Deuteranopia lack?
M (green)
What type of cone does a person with Tritanopia lack?
S (blue)
What is a unilateral dichromat?
A person with dichromatic vision in one eye and normal vision in the other.
What are the three colour opponent channels?
red-green
blue-yellow
white-black
How do afterimages work?
When you stare at the same colour for a while, those cones become less sensitive to the stimulus. When white is then shown, those cones respond weaker than other cones so another colour is seen and not white.
How do we achieve colour constancy?
Habituation
Discounting the illuminant
