Chapter 9 Flashcards
a type of color blindness caused by damage to the cerebral cortex of the brain, rather than abnormalities in the cells of the eye’s retina.
cerebral achromatopsia
partial color blindness
color deficiency
all shades except for black, white, and their mixture, gray.
chromatic colors
when some wavelengths of light are reflected more than others.
selective reflection
White, gray, black. Occurs when light is reflected equally across the spectrum.
achromatic colors
a graph that plots the percentage of light reflected from a given object at each wavelength in the visual spectrum.
reflectance curve
only some wavelengths pass through a given object or substance.
selective transmission
a graph that plots the percentage of light transmitted at each wavelength.
transmission curve
a new color created by the removal of wavelengths from a light with a broad spectrum of wavelengths.
subtractive color mixture
a new color created by a process that adds one set of wavelengths to another set of wavelengths.
additive color mixture
aka rainbow colors. A _________ is composed of a single fundamental color on the visible part of the electromagnetic spectrum, as opposed to a mixture of colors.
spectral colors
colors that do not appear in the spectrum because they are mixtures of other colors, such as magenta (a mixture of blue and red).
nonspectral colors
the intensity of a color
saturation
the hue of color when it takes on a faded or washed-out appearance.
desaturated
the light-to-dark dimension of color.
value/lightness
the 3-dimensional representation of a color model.
color solid
a color space that specifies colors based on 3 properties of color: hue (basic color), chroma (color intensity/ saturation), and value (lightness), created by Professor Albert H. Munsell.
Munsell color system
A proposal that color vision depends on the activity of 3 different receptor mechanisms. Aka Young-Helmholtz theory.
trichromacy of color vision
a procedure in which experimenters present a reference color, and the observer is asked to match the reference color by mixing different wavelengths of light.
color matching
a technique that directs a narrow beam of light into a single cone receptor. Helped to discover 3 types of cones in the human retina.
Microspectrophotometry
a technique that made it possible to look into a person’s eye and take pictures that showed how cones are arranged on the surface of the retina.
adaptive optical imaging
an imperfection that distorts the light on its way to the retina.
abberations
the resulting image of an adaptive optical image procedure. Shows foveal cones distinguished in short-, medium-, and long-wavelength cones.
cone mosaic
a situation in which two physically different stimuli are perceptually identical.
metamerism
the two identical fields in a color-matching experiment.
metamers
a rare form of color blindness that is usually hereditary and occurs in only about 10 people out of 1 million.
monochromatism
people with no functioning cones, so their vision is created only by the rods. (only seeing in shades of lightness- white, gray, black)
monochromats
a condition in which you see colors differently than most people. Makes it hard to tell the difference between certain colors.
colorblind
once a photon of light is absorbed by a visual pigment molecule, the identity of the light’s wavelength is lost.
principle of univariance
people with just two types of cone pigments. They can see chromatic colors, but because they have only two types of cones, they confuse some colors that trichromats can distinguish.
dichromats
what most people are, people that have 3 types of cones and can distinguish 3 primary colors.
trichromats
a stimulus used in a color vision test. (Numbers distinguished in dots of color)
Ishihara plates
a person with trichromatic vision in one eye and dichromatic vision in the other.
unilateral dichromat
3 major forms- protanopia, deuteranopia, and tritanopia. Protanopia and deuteranopia are the most common and are inherited through a gene located on the X chromosome. (sex-linked)
dichromatism
affects more males than females. A _____ is missing the long-wavelength pigment. As a result, a _____ perceives short-wavelength light as blue, and as the wavelength is increased, the blue becomes less and less saturated until, at 492 nm, the _____ perceives gray.
protanopia
the wavelength at which a protanope perceives gray.
neutral point
affects more males than females. A ______ is missing the medium-wavelength pigment. A _______perceives blue at short wavelengths, sees yellow at long wavelengths, and has a neutral point at about 498 nm.
deuteranopia
very rare, but still affects males more. A ______ is missing the short-wavelength pigment. A _____ perceives blue at short wavelengths, red at long wavelengths, and has a neutral point at 570 nm.
tritanopia
an _______needs 3 wavelengths to match any wavelength, just as a normal trichromat does. However, the anomalous trichromat mixes these wavelengths in different proportions from a trichromat, and an _________ is not as good as a trichromat at discriminating between wavelengths that are close together.
anomalous trichromatism
there are 2 pairs of chromatic colors, red-green and blue-yellow.
opponent-process theory of color vision
a figure that arranges perceptually similar colors next to each other around its perimeter.
color cirlce
base colors that create all the other colors through mixing the base colors.
primary colors
a method for estimating the underlying opponent response functions by asking observers to explicitly decompose each hue into the percentage contributed by the different primaries.
hue scaling
unmixed colors without a tint of any other colors (primary colors)
unique hue
red and green cancel each other as do yellow and blue.
hue cancellation
neurons that responded with an excitatory response to light from one part of the spectrum and with an inhibitory response to light from another part.
opponent neurons
we perceive the colors of objects as being relatively constant even under changing illumination.
color constancy
prolonged exposure to chromatic color.
chromatic adaptation
the perception of the object is shifted after adaptation, but not as much when there was no adaptation.
partial color constancy
the effect on perception of prior knowledge of the typical colors of objects.
memory color
people either see a blue and black dress or a white and gold dress.
TheDress
