Colour Flashcards
(75 cards)
What kinds of animals can see in colour?
Birds Fish Reptiles Insects Primates
(All other mammals, besides primates, don’t see colour)
How many types of cones do primates have in the eye that are used for colour vision?
Three
What is a biological advantage for colour vision (for primates)?
Colour vision adds contrast between objects and their background, which makes it useful in foraging for food
True or false: the cones in primates’ eyes are particularly beneficial for distinguishing red and orange against a green background
False
Distinguishes red and YELLOW
Birds are able to see colours in the UV range that others cannot see at all. What is the biological advantage of this?
Colours of a potential mate’s feathers indicate how healthy the bird is. Since they can see colours that other animals can’t, they can still communicate with other birds about how healthy they are while hiding from predators
How can colour vision in non-mammalian animals be used for foraging?
Bees see ultraviolet hues on flowers that act as nectar maps (invisible to humans)
What are the two different types of colour mixing?
Subtractive
Additive
What is subtractive colour mixing?
When you mix different colours and alter the combinations wavelengths that are absorbed (subtracted)— you’re subtracting wavelengths out
(Results from light that is reflected off of the surface)
If an object looks blue to us, does that means it’s reflecting or absorbing the “blue” wavelength?
Reflecting
It’s absorbing all of the other colours
What are the primary colours in subtractive mixing?
Cyan
Magenta
Yellow
(can make all of the colours in the rainbow)
What is additive colour mixing?
When coloured lights add their dominant colour to the mixture
What are the primary colours in additive mixing?
Red
Green
Blue
What is the complementary colour of red?
Cyan
What is the complementary colour of green?
Magenta
What is the complementary colour of blue?
Yellow
With additive mixing, when you mix a primary colour with its complement, you get _____ or _____
Grey or White
If you hold a magnifying glass to a yellow patch on a TV screen, what will you see?
A bunch of red and green dots (not yellow)
If two colours are close enough together, what will our visual system do?
Fuse them together
True or false: human colour perception is based on subtractive mixing
False
Additive mixing
What are the two theories of colour vision?
Trichromatic
Opponent-Process
What is the trichromatic theory of colour vision based on?
The proposal that the retina contains three diff kinds of receptors, each maximally sensitive/responsive to diff wavelengths of light
What is another name for the trichromatic theory of colour vision?
Young-Helmholtz theory
What does it mean when you say a receptor is ‘maximally responsive’?
Means that a given receptor will respond to other wavelengths less strongly than it would to its peak wavelength
When you perceive yellow, what does this indicate about the cones and their stimulation levels?
Red and green cones are equally stimulated