Chapter 9: Percieving color

Question 1

cerebral achromatopsia

Answer 1

color blindness caused by a cortical injury

Question 2

chromatic colors

Answer 2

such as blue, green, and red, occur when some wavelengths are reflected more than others

Question 3

selective reflection

Answer 3

when some wavelengths are reflected more than others

Question 4

reflectance curves

Answer 4

plot the percentage of light reflected from objects at each wavelength in the visible spectrum

Question 4

achromatic colors

Answer 4

such as white, gray and black occur when light is reflected equally across the spectrum

Question 5

selective transmission

Answer 5

only some wavelengths pass through the object or substance (ex. cranberry juice selectively transmits long wl light (red) and limade selective transmits mid wl light (green))

Question 6

transmission curves

Answer 6

the plots of the percentage of light transmitted at each wavelength

Question 7

subtractive color mixture

Answer 7

when you mix colors (like paints) and it subtracts all the wavelengths except some that are associated with the final color -> less wavelengths are reflected

Question 8

additive color mixture

Answer 8

like mixing lights, this happens when it involves adding up the wavelengths of each light in the mixture rather than subtracting (paints) -> more wavelengths are reflected

Question 9

saturation

Answer 9

the amount of white that has been added to a particular hue, saturation decreases as more white is added

Question 10

desaturated

Answer 10

when colors are desaturated they take on a faded or washed-out appearance

Question 11

hues

Answer 11

another term for chromatic colors

Question 12

value

Answer 12

refers to the light to dark dimension of color (light red vs dark red, adding of black)

Question 13

color solid

Answer 13

arranging colors systematically in a 3 dimensional solid

Question 14

HSV color solid

Answer 14

color solid with the three dimensions of hue, saturation, and color

Question 15

trichromatic theory of vision

Answer 15

states that color vision depends on the activity of three different receptior mechanisms.

Question 16

young-hemholtz theory

Answer 16

research that expanded upon the trichromatic theory with color matching experiments

Question 17

color matching

Answer 17

the experimenter provides a reference color, and thene the subject matches the color by missing different wavelengths of light in a comparison field. found tht participants needed at least 3 colors to make a new color

Question 18

metamerism

Answer 18

when two physically different stimuli are perceptually identical

Question 19

metamers

Answer 19

ex. the to identitcal fields in a color matching experiment, they aren’t completely identical but they are percived as identical

Question 20

principle of univariance

Answer 20

states that once a photon of light is absorbed by a visual pigment molecule, the identity of the light’s wavelength is lost.

Question 21

monochromats

Answer 21

people who see with just one pigment, so they see in shades of gray

Question 22

dichromats

Answer 22

people who 2 cone pigments, they see colors but cant distinguish some colors that trichromats can

Question 23

trichromats

Answer 23

people with 3 visual pigments

Question 24

opponent process theory

Answer 24

proposed by hering, color wisionis caused by opposing physiological responses generated by bkue and yellow, red and green, and black and white.

Question 25

color circle

Answer 25

arranges perceptually similar colors next to each other around its perimeter, only concerned with hue

Question 26

hering’s primary colors

Answer 26

red, yellow, green, or blue

Question 27

complementary afterimages

Answer 27

each afterimage is the color on the opposite side of the color circle

Question 28

hue cancellation

Answer 28

using the opposite color to cancel out the color (ex adding more and more yellow light to cancel out the blueness of the original color)

Question 29

single-opponent neurons

Answer 29

increases firing to medium wavelength presented to the enter of the receptive field and decreass firing to long wavelengths presented to the surround

Question 30

double-opponent neurons

Answer 30

receptive fields similar to simple cortical cells, usegul for percieving boundaries betwee different colors

Question 31

monochromatism

Answer 31

rare form of color blindness that is mainly hereditary and occurs in about only 10 peope out of 1 million, they only see in shades of lightness (black, grey, white)

Question 32

color blind

Answer 32

another word for monochromats, as compared to dichromats who are color deficient

Question 33

dichromatism

Answer 33

missing one of the 3 cone pigments, which means that they can experience color but not as many colors are trichromats can

Question 34

ishihara plates

Answer 34

color blind plates with the numbers in the middle

Question 35

unilateral dichromat

Answer 35

a person with trichromatic vision in one eye and dichromatic vision in the other

Question 36

protanopia

Answer 36

missing the long wavelength pigment,

Question 37

deuteranopia

Answer 37

missinf the medium wavelength pigment

Question 38

tritanopia

Answer 38

missing the short waelength

Question 39

anomalous trichromatism

Answer 39

mixes the wavelengths in different proportions from a trichromat and is not as good as discriminating between wavelengths that are close together

Question 40

color constancy

Answer 40

we percieve colors to be relatiely constant even under changing illumination

Question 41

chromatic adaptation

Answer 41

color perception cna be changed by prolonged exposure to chromatic color. ex. when you stare at a red swuare too long and then look away, things look green

Question 42

parital color constancy

Answer 42

the perception of the object is shifted after adaptation, but not as much as when there was no adaptation.

Question 43

memory color

Answer 43

if we know that an objects specific color, we percieve it as more saturated than objects with the same wavelengths , ex a stop sign

Question 44

lightness

Answer 44

the perception of the shade of achromatic color

Question 45

lightness constancy

Answer 45

the fact that we see white, blacks and grays as staying about the same shade under different illuminations

Question 46

ratio principle

Answer 46

as long as the ratio between the reflectance of the bject to the reflectnce of surrounding objects then the percieved lightness will stay the same

Question 47

reflectance edge

Answer 47

an edge where the reflectance of two surfaces changes

Question 48

illumination edge

Answer 48

an edge where the lighting changes

Question 49

penumbra

Answer 49

the fuzzy border at the end of a shadow

Question 50

spectral colors

Answer 50

colors in the visible spectrum (red orange yellow, green , blue, violet, (sometimes indigo))

Question 51

non spectral colors

Answer 51

colors that do not appear in the spectrum, but they are a mixture of different colors like magenta (mix of blue and red)