People can distinguish 150 to 200 main colors and seven million different colors {vision, color} {color vision}, by representing the light intensity-frequency spectrum and separating it into categories.
color: spectrum
Colors range continuously from red to scarlet, vermilion, orange, yellow, chartreuse, green, spring green, cyan, turquoise, blue, indigo (ultramarine), violet, magenta, crimson, and back to red. Scarlet is red with some orange. Vermilion is half red and half orange. Chartreuse is half yellow and half green. Cyan is half green and half blue. Turquoise is blue with some green. Indigo is blue with some red. Violet is blue with more red. Magenta is half blue and half red. Crimson is red with some blue.
color: definition
Blue, green, and yellow have definite wavelengths at which they are pure, with no other colors. Red has no definite wavelength at which it is pure. Red excites mainly long-wavelength receptor. Yellow is at long-wavelength-receptor maximum-sensitivity wavelength. Green is at middle-wavelength-receptor maximum-sensitivity wavelength. Blue is at short-wavelength-receptor maximum-sensitivity wavelength.
color: similarities
Similar colors have similar average light-wave frequencies. Colors with more dissimilar average light-wave frequencies are more different.
color: opposites
Complementary colors are opposite colors, and white and black are opposites.
color: animals
Primates have three cone types. Non-mammal vertebrates have one cone type, have no color opponent process, and detect colors from violets to reds, with poorer discrimination than mammals.
Mammals have two cone types. Mammals have short-wavelength receptor and long-wavelength receptor. For example, dogs have receptor with maximum sensitivity at 429 nm, which is blue for people, and receptor with maximum sensitivity at 555 nm, which is yellow-green for people. Mammals can detect colors from violets to reds, with poorer discrimination than people.
With two cone types, mammals have only one color opponency, yellow-blue. Perhaps, mammals cannot see phenomenal colors because color sensations require two opponent processes.
nature: individuality
People's vision processes are similar, so everyone's vision perceptions are similar. All people see the same color spectrum, with the same colors and color sequence. Colorblind people have consistent but incomplete spectra.
nature: objects
Colors are surface properties and are not essential to object identity.
nature: perception
Colors are not symmetric, so colors have unique relations. Colors cannot substitute. Colors relate in only one consistent and complete way, and can mix in only one consistent and complete way.
nature: subjective
No surface or object physical property corresponds to color. Color depends on source illumination and surface reflectance and so is subjective, not objective.
nature: irreducibility
Matter and energy cannot cause color, though experience highly correlates with physical quantities. Light is only electromagnetic waves.
processes: coloring
Three coloring methods are coloring points, coloring areas, or using separate color overlays. Mind colors areas, not points or overlays, because area coloring is discrete and efficient.
processes: edge enhancement
Adjacent colors enhance their contrast by adding each color's complementary color to the other color. Adjacent black and white also have enhanced contrast.
processes: timing
Different color-receptor-system time constants cause color.
processes: precision
People can detect smaller wavelength differences between 500 nm and 600 nm than above 600 nm or below 500 nm, because two cones have maximum sensitivities within that range.
physical: energy and color
Long-wavelength photons have less energy, and short-wavelength photons have more energy, because photon energy relates directly to frequency.
physical: photons
Photons have emissions, absorptions, vibrations, reflections, and transmissions.
physical: reflectance
Color depends on both illumination and surface reflectance [Land, 1977]. Comparing surface reflective properties to other or remembered surface reflective properties results in color.
physical: scattering
Blue light has shorter wavelength and has more refraction and scattering by atoms.
Long-wavelength and medium-wavelength cones have similar wavelength sensitivity maxima, so scattering and refraction are similar. Fovea has no short-wavelength cones, for better length precision.
mixing
Colors from light sources cannot add to make red or to make blue. Colors from pigment reflections cannot add to make red or to make blue.
properties: alerting and calming colors
Psychologically, red is alerting color. Green is neutral color. Blue is calming color.
properties: contraction and expansion by color
Blue objects appear to go farther away and expand, and red objects appear to come closer and contract, because reds appear lighter and blues darker.
properties: color depth
Color can have shallow or deep depth. Yellow is shallow. Green is medium deep. Blue and red are deep.
Perhaps, depth relates to color opponent processes. Red and blue mainly excite one receptor. Yellow and green mainly excite two receptors. Yellow mixes red and green. Green mixes blue and yellow.
properties: light and dark colors
Yellow is the brightest color, comparable to white. In both directions from yellow, darkness grows. Colors darken from yellow toward red. Colors darken from yellow toward green and blue. Green is lighter than blue, which is comparable to black.
properties: sad and glad
Dark colors are sad and light colors are glad, because dark colors are less bright and light colors are more bright.
properties: warm and cool colors
Colors can be relatively warm or cool. Black-body-radiator spectra center on red at 3000 K, blue at 5000 K, and white at 7000 K. Light sources have radiation surface temperature {color temperature} comparable to black-body-radiator surface temperature. However, people call blue cool and red warm, perhaps because water and ice are blue and fires are red, and reds seem to have higher energy output. Warm pigments have more saturation and are lighter than cool pigments. White, gray, and black, as color mixtures, have no net temperature.
properties: hue change
Colors respond differently as hue changes. Reds and blues change more slowly than greens and yellows.
factors
Colors change with illumination intensity, illumination spectrum, background surface, adjacent surface, distance, and viewing angle. Different people vary in what they perceive as unique yellow, unique green, and unique blue. The same person varies in what they perceive as unique yellow, unique green, and unique blue.
realism and subjectivism
Perhaps, color relates to physical objects, events, or properties {color realism} {color objectivism}. Perhaps, color is identical to a physical property {color physicalism}, such as surface spectral reflectance distribution {reflectance physicalism}. Perhaps, colors are independent of subject and condition. Mental processes allow access to physical colors.
Perhaps, colors depend on subject and physical conditions {color relationism} {color relativism}.
Perhaps, things have no color {color eliminativism}, and color is only in mind. Perhaps, colors are mental properties, events, or processes {color subjectivism}. Perhaps, colors are mental properties of mental objects {sense-datum, color}. Perhaps, colors are perceiver mental processes or events {adverbialism, color}. Perhaps, humans perceive real properties that cause phenomenal color. Perhaps, colors are only things that dispose mind to see color {color dispositionalism}. Perhaps, colors depend on action {color enactivism}. Perhaps, colors depend on natural selection requirements {color selectionism}. Perhaps, colors depend on required functions {color functionalism}. Perhaps, colors represent physical properties {color representationalism}. Perhaps, experience has color content {color intentionalism}, which provides information about surface color.
Perhaps, humans know colors, essentially, by experiencing them {doctrine of acquaintance}, though they can also learn information about colors.
Perhaps, colors are identical to mental properties that correspond to color categories {corresponding category constraint}.
Properties {determinable property} can be about categories, such as blue. Properties {determinate property} can be about specific things, such as unique blue, which has no red or green.
Perhaps, there are color illusions due to illumination intensity, illumination spectrum, background surface, adjacent surface, distance, and viewing angle. Human color processing cannot always process the same way or to the same result. Color names and categories have some correspondence with other animals, infants, and cultures, but vary among scientific observers and by introspection.
How can colors be in mind but appear in space? Subjectivism cannot account for the visual field. Objectivism cannot account for the color facts.
Differences among objective object and physical properties, subjective color processing, and relations among surfaces, illumination, background, viewing angle and distance do not explain perceived color differences {explanatory gap, color}.
Consciousness>Consciousness>Sense>Vision>Color Vision
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Date Modified: 2022.0224