Color Perception and Physical Properties
– Color is based on the electromagnetic spectrum.
– Color perception is related to light absorption, reflection, emission spectra, and interference.
– Humans perceive colors in the visible light spectrum with three types of cone cells.
– Different animals may have a different number of cone cell types or different color sensitivity ranges.
– Animal perception of color originates from different light wavelengths and is processed by the brain.
– Spectral colors are those that can be produced by visible light of a single wavelength.
– They have 100% purity and are fully saturated.
– A complex mixture of spectral colors can describe any color.
– The division of spectral colors into distinct colors is culturally and historically contingent.
– The inclusion/exclusion of colors in the spectrum is a matter of debate, such as indigo and cyan.
– The physical color of an object depends on how it absorbs and scatters light.
– Transparent objects allow light to transmit through and are perceived as colorless.
– Opaque objects do not allow light to transmit through and instead absorb or reflect it.
– Translucent objects scatter or absorb certain wavelengths of light, resulting in perceived color.
– Absorbed light in objects is often dissipated as heat.
– Color vision is the ability to perceive and distinguish different colors.
– The source of the color sensation is light.
– Theories of color vision have been developed throughout history, starting with Aristotle and Newton.
– Thomas Young proposed the trichromatic theory, stating that any color can be matched with a combination of three lights.
– Color vision is influenced by context and can lead to perceptual differences.
Development of Theories of Color Vision
– Newton identified light as the source of the color sensation.
– Goethe published his Theory of Colors, providing a rational description of color experience.
– Thomas Young proposed the trichromatic theory of color vision.
– James Clerk Maxwell and Hermann von Helmholtz further refined the trichromatic theory.
– Theories of color vision explain how color originates rather than defining what it is.
Nonstandard Color Perception
– Color vision deficiency causes individuals to perceive a smaller gamut of colors.
– Deficiency can range from lower color resolution to complete lack of color perception.
– Most common form is congenital red-green color blindness, affecting ~8% of males.
– Cerebral achromatopsia caused by neural anomalies in visual processing areas of the brain.
– Tetrachromacy observed in most vertebrates and some invertebrates, enabling perception of additional distinct colors.
Color Processing in the Brain
– Color information transmitted by three opponent processes or channels.
– Red-green, blue-yellow, and black-white channels account for color experience.
– Color perception beyond retina processing is a matter of philosophical dispute.
– Visual dorsal and ventral streams responsible for color perception.
– Area V4 in the brain processes color and form associated with color.
Color Applications and Phenomena
– Synesthesia is a condition where perceiving one sensory input triggers another sensory experience.
– After exposure to strong light, photoreceptors become desensitized.
– Desensitized photoreceptors result in colors appearing lacking the color component detected by those photoreceptors.
– Afterimages occur when the eye continues to see a bright figure in a complementary color after looking away.
– Color constancy refers to the ability of the visual system to perceive consistent colors despite changes in illumination.
– Color reproduction is the science of creating colors that faithfully represent the desired color for human perception.
– Additive color mixing combines different colors of light to create new colors.
– Subtractive color mixing involves using dyes, inks, pigments, or filters to absorb certain wavelengths of light.
– Structural colors are produced by interference effects rather than pigments.
– Colors and their associations play a significant role in art and literature.
– Different cultures attribute various meanings and symbolism to colors.
– Color psychology explores the effects of color on human emotion and behavior.
– Chromotherapy, an alternative medicine practice, uses colors for healing purposes. Source: https://en.wikipedia.org/wiki/Color
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Color (American English) or colour (Commonwealth English) is the visual perception based on the electromagnetic spectrum. Though color is not an inherent property of matter, color perception is related to an object's light absorption, reflection, emission spectra and interference. For most humans, colors are perceived in the visible light spectrum with three types of cone cells (trichromacy). Other animals may have a different number of cone cell types or have eyes sensitive to different wavelength, such as bees that can distinguish ultraviolet, and thus have a different color sensitivity range. Animal perception of color originates from different light wavelength or spectral sensitivity in cone cell types, which is then processed by the brain.
Colors have perceived properties such as hue, colorfulness (saturation) and luminance. Colors can also be additively mixed (commonly used for actual light) or subtractively mixed (commonly used for materials). If the colors are mixed in the right proportions, because of metamerism, they may look the same as a single-wavelength light. For convenience, colors can be organized in a color space, which when being abstracted as a mathematical color model can assign each region of color with a corresponding set of numbers. As such, color spaces are an essential tool for color reproduction in print, photography, computer monitors and television. The most well-known color models are RGB, CMYK, YUV, HSL and HSV.
Because the perception of color is an important aspect of human life, different colors have been associated with emotions, activity, and nationality. Names of color regions in different cultures can have different, sometimes overlapping areas. In visual arts, color theory is used to govern the use of colors in an aesthetically pleasing and harmonious way. The theory of color includes the color complements; color balance; and classification of primary colors (traditionally red, yellow, blue), secondary colors (traditionally orange, green, purple) and tertiary colors. The study of colors in general is called color science or colorology.
