L3 - Colour Flashcards
What did Gegenfurtner (2015) say about people, colour and how they perceive the dress?
Those who said the dress was blue and black tended to see darker shades of blue-black in the colour wheel.
Those who saw the dress as white and gold saw more pale blue and Mongolia brown colours.
The study by Gegenfurtner (2015) demonstrates what about colour naming?
Seeing the dress in different colours isn’t about colour naming - people are genuinely seeing different colours in the image.
Which levels of light are rods used for?
Dim light/night vision
Which levels of light are cones used for?
Day vision/colour vision
Where is colour processed?
V4 –> V8
What would happen if we only had one cone type? (just one of blue, red, green)
We would see everything in colour, but the different colours we perceive would be indistinguishable.
What is it called if we only had one cone type/colour?
Cone monochromats
What do people with colour blindness have problems with?
Miss tuned cone types, meaning they can’t discriminate between certain colours very well.
What is the most common form of colour blindness?
Miss-tuned green cones (deuteranomaly - lack of sensitivity to green light)
What are rod monochromats?
People with no cones at all, which leads to huge deficits seeing in daylight.
Which colour cones are carried on the X chromosome?
Red and green
What is cortical colour blindness?
Damage inflicted to area V8, leading to an inability to discriminate red squares from green squares. (sufferers can still discriminate between lighter squares and darker ones.
What information does luminance provide?
Information about clear shapes
What information does the blue-yellow channel provide?
Shadows vs sunlight
What information does the red-green channel provide?
Red-green colour comparisons
Which area is responsible for the conscious perception of colour?
V8
What is the difference between colour addition and colour subtraction?
Addition involves the creation of colour through the combination of varying intensities of other colours/light.
Subtraction involves the absorption of different intensities of light
What is the problem with adding the blue cone to the yellow in terms of the resulting vision?
Visual acuity is affected detrimentally. Although some differences in colour can now be seen, the detail and acuity of vision decreases.
Why is visual acuity lower with yellow and blue cones, compared with yellow cones alone?
Short-wave light (blue-ish colours) is always out of focus in the eye, due to a defect called chromatic aberration.
Are there more yellow cones or blue cones in the retina and why?
Yellow - as few blue as possible to avoid further decreases in visual acuity.
Which cone type is absent in the fovea of our retinas?
Blue cones.
What percentage of blue cones are in our retina?
10%
How is luminance created from the output of cones??
Luminance is created from the sum of the activity of red and green cell types.
How is red-green colour created from the output of cone types?
Red cone output is divided by green cone output to allow the brain to interpret red-green colour.
