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Encyclopedia > Visible spectrum

The visible spectrum (or sometimes called the optical spectrum) is the portion of the electromagnetic spectrum that is visible to (can be detected by) the human eye. Electromagnetic radiation in this range of wavelengths is called visible light or simply light. A typical human eye will respond to wavelengths in air from about 380 to 750 nm.[1] The corresponding wavelengths in water and other media are reduced by a factor equal to the refractive index. In terms of frequency, this corresponds to a band in the vicinity of 400-790 terahertz. A light-adapted eye generally has its maximum sensitivity at around 555 nm (540 THz), in the green region of the optical spectrum (see: luminosity function). The spectrum does not, however, contain all the colors that the human eyes and brain can distinguish. Brown, pink, and magenta are absent, for example, because they need a mix of multiple wavelengths, preferably shades of red. Visible light may be: Light in the visible spectrum A work included in The Collected Short Fiction of C. J. Cherryh Category: ... Image File history File links Srgbspectrum. ... Although some radiations are marked as N for no in the diagram, some waves do in fact penetrate the atmosphere, although extremely minimally compared to the other radiations The electromagnetic (EM) spectrum is the range of all possible electromagnetic radiation. ... In psychology, visual perception is the ability to interpret visible light information reaching the eyes which is then made available for planning and action. ... For other uses, see Eye (disambiguation). ... This box:      Electromagnetic (EM) radiation is a self-propagating wave in space with electric and magnetic components. ... For other uses, see Wavelength (disambiguation). ... For other uses, see Light (disambiguation). ... Look up air in Wiktionary, the free dictionary. ... To help compare different orders of magnitude this page lists lengths between 10-7 and 10-6 m (100 nm and 1 µm). ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ... The hertz (symbol: Hz) is the SI unit of frequency. ... For other uses, see Light (disambiguation). ... A nanometre (American spelling: nanometer, symbol nm) (Greek: νάνος, nanos, dwarf; μετρώ, metrÏŒ, count) is a unit of length in the metric system, equal to one billionth of a metre (or one millionth of a millimetre), which is the current SI base unit of length. ... For other uses, see Green (disambiguation). ... The luminosity function is a standard function established by the Commission Internationale de lÉclairage to account for the variable sensitivity of the human eye to radiation at different wavelengths. ... Color is an important part of the visual arts. ... For other uses, see Brown (disambiguation). ... This article is about the color. ... Magenta is a color made up of equal parts of red and blue light. ...

White light dispersed by a prism into the colors of the optical spectrum.
White light dispersed by a prism into the colors of the optical spectrum.

Wavelengths visible to the eye also pass through the "optical window", the region of the electromagnetic spectrum which passes largely unattenuated through the Earth's atmosphere (although blue light is scattered more than red light, which is the reason the sky is blue). The response of the human eye is defined by subjective testing (see CIE), but the atmospheric windows are defined by physical measurement. The "visible window" is so called because it overlaps the human visible response spectrum; the near infrared (NIR) windows lie just out of human response window, and the Medium Wavelength IR (MWIR) and Long Wavelength or Far Infrared (LWIR or FIR) are far beyond the human response region. prism splitting light Source: NASA File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... prism splitting light Source: NASA File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... For other uses, see Light (disambiguation). ... Diagram of a triangular prism, dispersing light Lamps as seen through a prism. ... In astronomy, the optical window is that portion of the electromagnetic spectrum that passes through the atmosphere all the way to the ground. ... Air redirects here. ... Scattering is a general physical process whereby some forms of radiation, such as light, sound or moving particles, for example, are forced to deviate from a straight trajectory by one or more localized non-uniformities in the medium through which it passes. ... The CIE 1931 color space chromaticity diagram with wavelengths in nanometers. ...


The eyes of many species perceive wavelengths different from the spectrum visible to the human eye. For example, many insects, such as bees, can see light in the ultraviolet, which is useful for finding nectar in flowers. For this reason, plant species whose life cycles are linked to insect pollination may owe their reproductive success to their appearance in ultraviolet light, rather than how colorful they appear to our eyes. For other uses, see Species (disambiguation). ... Orders Subclass Apterygota Archaeognatha (bristletails) Thysanura (silverfish) Subclass Pterygota Infraclass Paleoptera (Probably paraphyletic) Ephemeroptera (mayflies) Odonata (dragonflies and damselflies) Infraclass Neoptera Superorder Exopterygota Grylloblattodea (ice-crawlers) Mantophasmatodea (gladiators) Plecoptera (stoneflies) Embioptera (webspinners) Zoraptera (angel insects) Dermaptera (earwigs) Orthoptera (grasshoppers, etc) Phasmatodea (stick insects) Blattodea (cockroaches) Isoptera (termites) Mantodea (mantids) Psocoptera... For other uses, see Western honey bee and Bee (disambiguation). ... For other uses, see Ultraviolet (disambiguation). ... Nectar of camellia Nectar, in botany, is a sugar-rich liquid produced by the flowers of plants in order to attract pollinating animals. ... For other uses, see Flower (disambiguation). ...

Contents

History

Two of the earliest explanations of the optical spectrum came from Isaac Newton, when he wrote his Opticks, and from Goethe, in his Theory of Colours, although earlier observations had been made by Roger Bacon who first recognized the visible spectrum in a glass of water, four centuries before Newton discovered that prisms could disassemble and reassemble white light.[2] Sir Isaac Newton FRS (4 January 1643 – 31 March 1727) [ OS: 25 December 1642 – 20 March 1727][1] was an English physicist, mathematician, astronomer, natural philosopher, and alchemist. ... Opticks or a treatise of the reflections, refractions, inflections and colours of light Opticks is a book written by English physicist Isaac Newton that was released to the public in 1704. ... Johann Wolfgang Goethe  , IPA: , later von Goethe, (28 August 1749 – 22 March 1832) was a German polymath: he was a poet, novelist, dramatist, humanist, scientist, theorist, painter, and for ten years chief minister of state for the duchy of Weimar. ... Theory of Colours (original German title, Zur Farbenlehre) is a book published by Johann Wolfgang von Goethe in 1810. ... For the Nova Scotia premier see Roger Bacon (politician). ...

Newton's color circle, showing the colors correlated with musical notes and symbols for the planets. The spectrum aligns with the colors from violet, around the circle, to red, but Newton's circle failed to indicate the discontinuity in closing the circle from red back to violet; this is where the purple colors fall.
Newton's color circle, showing the colors correlated with musical notes and symbols for the planets. The spectrum aligns with the colors from violet, around the circle, to red, but Newton's circle failed to indicate the discontinuity in closing the circle from red back to violet; this is where the purple colors fall.

Newton first used the word spectrum (Latin for "appearance" or "apparition") in print in 1671 in describing his experiments in optics. Newton observed that, when a narrow beam of sunlight strikes the face of a glass prism at an angle, some is reflected and some of the beam passes into and through the glass, emerging as different colored bands. Newton hypothesized that light was made up of "corpuscles" (particles) of different colors, and that the different colors of light moved at different speeds in transparent matter, with red light moving more quickly in glass than violet light. The result is that red light was bent (refracted) less sharply than violet light as it passed through the prism, creating a spectrum of colors. Image File history File links Newton's_colour_circle. ... Image File history File links Newton's_colour_circle. ... This article is about the color. ... For other uses, see Latins and Latin (disambiguation). ... In the scientific method, an experiment (Latin: ex- periri, of (or from) trying) is a set of observations performed in the context of solving a particular problem or question, to retain or falsify a hypothesis or research concerning phenomena. ... See also list of optical topics. ... Prism splitting light High Resolution Solar Spectrum Sunlight in the broad sense is the total spectrum of the electromagnetic radiation given off by the Sun. ... This article is about the material. ... Diagram of a triangular prism, dispersing light Lamps as seen through a prism. ... This article is about angles in geometry. ... The reflection of a bridge in Indianapolis, Indianas Central Canal. ... Corpuscle is J.J. Thomsons term for a subatomic particle similar to the electron. ... For the property of metals, see refraction (metallurgy). ...


Newton divided the spectrum into seven named colors: red, orange, yellow, green, blue, indigo, and violet (this order being popularly memorised by schoolchildren using the mnemonic ROY G. BIV). He chose seven colors out of a belief, derived from the ancient Greek sophists, that there was a connection between the colors, the musical notes, the known objects in the solar system, and the days of the week.[3][4] The human eye is relatively insensitive to indigo's frequencies, and some otherwise well-sighted people cannot distinguish indigo from blue and violet. For this reason some commentators including Isaac Asimov have suggested that indigo should not be regarded as a color in its own right but merely as a shade of blue or violet. For other uses, see Red (disambiguation). ... The orange, the fruit from which the modern name of the orange colour comes. ... This article is about the color. ... For other uses, see Green (disambiguation). ... This article is about the colour. ... Indigo is the color on the spectrum between about 450 and 420 nm in wavelength, placing it between blue and violet. ... Violet (named after the flower violet) is used in two senses: first, referring to the color of light at the short-wavelength end of the visible spectrum, approximately 380–420 nanometres (this is a spectral color). ... Wikiquote has a collection of quotations related to: English mnemonics#Science Roy G. Biv is a traditional mnemonic for the sequence of hues in the visible spectrum, in simple rainbows, and in order from longest to shortest wavelength: Red Orange Yellow Green Blue Indigo Violet The colors are arranged in... Sophism was originally a term for the techniques taught by a highly respected group of philosophy and rhetoric teachers in ancient Greece. ... This article is about the Solar System. ... Isaac Asimov (January 2?, 1920?[1] – April 6, 1992), pronounced , originally Исаак Озимов but now transcribed into Russian as Айзек Азимов [1], was a Russian-born American author and professor of biochemistry, a highly successful writer, best known for his works of science fiction and for his popular science books. ...


Johann Wolfgang von Goethe contended that the continuous spectrum was a compound phenomenon. Whereas Newton narrowed the beam of light in order to isolate the phenomenon, Goethe observed that with a wider aperture, there was no spectrum - rather there were reddish-yellow edges and blue-cyan edges with white between them, and the spectrum only arose when these edges came close enough to overlap. Goethe redirects here. ... This article is about the color. ...


All light travels at the same speed in a vacuum. The speed of light within a material is lower than the speed of light in a vacuum, and the ratio of speeds is known as the refractive index of the material. Because the refractive index (and thus the speed) of a wave in a material depends on its frequency (in accordance with a dispersion relation), light consisting of multiple frequencies—for instance white light—will be dispersed at the interface between the material and air or vacuum. Both water and glass can be used to demonstrate dispersion; a glass prism yields an optical spectrum from white light, and rainbows are an ideal example of natural refraction of the visible spectrum. Look up Vacuum in Wiktionary, the free dictionary. ... The speed of light in a vacuum is an important physical constant denoted by the letter c for constant or the Latin word celeritas meaning swiftness.[1] It is the speed of all electromagnetic radiation, including visible light, in a vacuum. ... The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ... The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ... For other uses, see Frequency (disambiguation). ... The relation between the energy of a system and its corresponding momentum is known as its dispersion relation. ... Dispersion of a light beam in a prism. ... Look up prism in Wiktionary, the free dictionary. ... For other uses, see Rainbow (disambiguation). ...


Spectral colors

Color Wavelength
violet 380–450 nm
blue 450–495 nm
green 495–570 nm
yellow 570–590 nm
orange 590–620 nm
red 620–750 nm

The familiar colors of the rainbow in the spectrum include all those colors that can be produced by visible light of a single wavelength only, the pure spectral or monochromatic colors. Image File history File links Spectrum4websiteEval. ... Color is an important part of the visual arts. ... For other uses, see Wavelength (disambiguation). ... Violet (named after the flower violet) is used in two senses: first, referring to the color of light at the short-wavelength end of the visible spectrum, approximately 380–420 nanometres (this is a spectral color). ... This article is about the colour. ... For other uses, see Green (disambiguation). ... This article is about the color. ... The orange, the fruit from which the modern name of the orange colour comes. ... For other uses, see Red (disambiguation). ... For other uses, see Rainbow (disambiguation). ...


Although the spectrum is continuous and therefore there are no clear boundaries between one color and the next, the ranges may be used as an approximation.[5]


Spectroscopy

Rough plot of Earth's atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation, including visible light.
Rough plot of Earth's atmospheric transmittance (or opacity) to various wavelengths of electromagnetic radiation, including visible light.

The scientific study of objects based on the spectrum of the light they emit is called spectroscopy. One particularly important application of spectroscopy is in astronomy, where spectroscopy is essential for analysing the properties of distant objects. Typically, astronomical spectroscopy utilises high-dispersion diffraction gratings to observe spectra at very high spectral resolutions. Helium was first detected through an analysis of the spectrum of the Sun; chemical elements can be detected in astronomical objects by emission lines and absorption lines; the shifting of spectral lines can be used to measure the redshift or blueshift of distant or fast-moving objects. The first exoplanets to be discovered were found by analysing the doppler shift of stars at such a high resolution that variations in their radial velocity as small as a few metres per second could be detected: the presence of planets was revealed by their gravitational influence on the stars analysed, as revealed by their motion paths. Image File history File links Download high resolution version (1650x1049, 189 KB)Plot of the transmittance/opacity of the atmosphere to electromagnetic radiation. ... Image File history File links Download high resolution version (1650x1049, 189 KB)Plot of the transmittance/opacity of the atmosphere to electromagnetic radiation. ... This article is about Earth as a planet. ... Air redirects here. ... A substance or object that is opaque is neither transparent nor translucent. ... For other uses, see Wavelength (disambiguation). ... This box:      Electromagnetic (EM) radiation is a self-propagating wave in space with electric and magnetic components. ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... Animation of the dispersion of light as it travels through a triangular prism. ... For other uses, see Astronomy (disambiguation). ... High resolution spectrum of the Sun showing thousands of elemental absorption lines (fraunhofer lines). ... To meet Wikipedias quality standards, this article or section may require cleanup. ... General Name, symbol, number helium, He, 2 Chemical series noble gases Group, period, block 18, 1, s Appearance colorless Standard atomic weight 4. ... Sol redirects here. ... The periodic table of the chemical elements A chemical element, or element, is a type of atom that is distinguished by its atomic number; that is, by the number of protons in its nucleus. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... This article is about the physical phenomenon. ... Blue shift is the opposite of redshift, the latter being much more noted due to its importance to modern astronomy. ... Infrared Image of a possible extrasolar planet (lower left) in the Constellation Taurus, taken by the Hubble Space Telescope. ... Any planet is an extremely faint light source compared to its parent star. ... The Doppler effect is the apparent change in frequency or wavelength of a wave that is perceived by an observer moving relative to the source of the waves. ... Radial velocity is the velocity of an object in the direction of the line of sight. ... Metre per second (U.S. spelling: meter per second) is an SI derived unit of both speed (scalar) and velocity (vector), defined by distance in metres divided by time in seconds. ... Gravity is a force of attraction that acts between bodies that have mass. ...


Color display spectrum

Color display spectrum. The narrow red, green and blue bars show the relative mixture of the three primary colors used to produce the color directly above.
Color display spectrum. The narrow red, green and blue bars show the relative mixture of the three primary colors used to produce the color directly above.

Color displays (e.g., computer monitors or televisions) mix red, green, and blue color to approximate the color spectrum. In the illustration, the narrow red, green and blue bars show the relative mixture of these three colors used to produce the color directly above. Image File history File links Computer_color_spectrum. ... Image File history File links Computer_color_spectrum. ... Nineteen inch (48 cm) CRT computer monitor A computer display, monitor or screen is a computer peripheral device capable of showing still or moving images generated by a computer and processed by a graphics card. ... An American family watching television in the 1950s. ... For other uses, see Red (disambiguation). ... For other uses, see Green (disambiguation). ... This article is about the colour. ...


See also

Wikisource has original text related to this article:
a debate whether indigo is the color meant on the spectrum

Image File history File links Wikisource-logo. ... The original Wikisource logo. ... Color vision is the capacity of an organism or machine to distinguish objects based on the wavelengths (or frequencies) of the light they reflect or emit. ... Theory of Colours (original German title, Zur Farbenlehre) is a book published by Johann Wolfgang von Goethe in 1810. ...

References

  1. ^ Cecie Starr (2005). Biology: Concepts and Applications. Thomson Brooks/Cole. ISBN 053446226X. 
  2. ^ Coffey, Peter (1912). The Science of Logic: An Inquiry Into the Principles of Accurate Thought. Longmans. 
  3. ^ Hutchison, Niels (2004). Music For Measure: On the 300th Anniversary of Newton's Opticks. Colour Music. Retrieved on 2006-08-11.
  4. ^ Newton, Isaac (1704). Opticks. 
  5. ^ Thomas J. Bruno, Paris D. N. Svoronos. CRC Handbook of Fundamental Spectroscopic Correlation Charts. CRC Press, 2005.
Year 2006 (MMVI) was a common year starting on Sunday of the Gregorian calendar. ... is the 223rd day of the year (224th in leap years) in the Gregorian calendar. ... Sir Isaac Newton FRS (4 January 1643 – 31 March 1727) [ OS: 25 December 1642 – 20 March 1727][1] was an English physicist, mathematician, astronomer, natural philosopher, and alchemist. ... Opticks or a treatise of the reflections, refractions, inflections and colours of light Opticks is a book written by English physicist Isaac Newton that was released to the public in 1704. ... Although some radiations are marked as N for no in the diagram, some waves do in fact penetrate the atmosphere, although extremely minimally compared to the other radiations The electromagnetic (EM) spectrum is the range of all possible electromagnetic radiation. ... This article is about electromagnetic radiation. ... In the NATO phonetic alphabet, X-ray represents the letter X. An X-ray picture (radiograph) taken by Röntgen An X-ray is a form of electromagnetic radiation with a wavelength approximately in the range of 5 pm to 10 nanometers (corresponding to frequencies in the range 30 PHz... For other uses, see Ultraviolet (disambiguation). ... For other uses, see Infrared (disambiguation). ... Electromagnetic waves sent at terahertz frequencies, known as terahertz radiation, terahertz waves, terahertz light, T-rays, T-light, T-lux and THz, are in the region of the electromagnetic spectrum between 300 gigahertz (3x1011 Hz) and 3 terahertz (3x1012 Hz), corresponding to the wavelength range starting at submillimeter (<1 millimeter... This article is about the type of Electromagnetic radiation. ... Violet (named after the flower violet) is used in two senses: first, referring to the color of light at the short-wavelength end of the visible spectrum, approximately 380–420 nanometres (this is a spectral color). ... This article is about the colour. ... For other uses, see Green (disambiguation). ... This article is about the color. ... The orange, the fruit from which the modern name of the orange colour comes. ... For other uses, see Red (disambiguation). ... This article is about the type of Electromagnetic radiation. ... The W band of the microwave part of the electromagnetic spectrum and ranges from 75 to 111 GHz. ... The V band (vee-band) of the electromagnetic spectrum ranges from 50 to 75 GHz. ... The Ka band (kurz-above band) is a portion of the K band of the microwave band of the electromagnetic spectrum. ... K band is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging between 12 to 63 GHz. ... The Ku band (kay-yoo kurz-under band) is a portion of the electromagnetic spectrum in the microwave range of frequencies ranging from 11 to 18 GHz. ... The X band (3-cm radar spot-band) of the microwave band of the electromagnetic spectrum roughly ranges from 5. ... C band (compromise band) is a portion of electromagnetic spectrum in the microwave range of frequencies ranging from 4 to 6 GHz. ... The S band ranges from 2 to 4 GHz. ... L band (20-cm radar long-band) is a portion of the microwave band of the electromagnetic spectrum ranging roughly from 0. ... Radio frequency, or RF, refers to that portion of the electromagnetic spectrum in which electromagnetic waves can be generated by alternating current fed to an antenna. ... Extremely high frequency is the highest radio frequency band. ... Microwave Slang for small waves, like at a beach, often used by surfers. ... This article is about the radio frequency. ... Very high frequency (VHF) is the radio frequency range from 30 MHz (wavelength 10 m) to 300 MHz (wavelength 1 m). ... High frequency (HF) radio frequencies are between 3 and 30 MHz. ... Medium frequency (MF) refers to radio frequencies (RF) in the range of 300 kHz to 3000 kHz. ... Low Frequency or LF refers to Radio Frequencies (RF) in the range of 30–300 kHz. ... Very low frequency or VLF refers to radio frequencies (RF) in the range of 3 to 30 kHz. ... Ultra Low Frequency (ULF) is the frequency range between 300 hertz and 3000 hertz. ... Super Low Frequency (SLF) is the frequency range between 30 hertz and 300 hertz. ... Extremely low frequency (ELF) is the band of radio frequencies from 3 to 30 Hz. ... For other uses, see Wavelength (disambiguation). ... This article is about the type of Electromagnetic radiation. ... A solid-state, analog shortwave receiver Shortwave radio operates between the frequencies of 3 MHz (3,000 kHz) and 30 MHz (30,000 kHz) [1] and came to be referred to as such in the early days of radio because the wavelengths associated with this frequency range were shorter than... Mediumwave radio transmissions serves as the most common band for broadcasting. ... This article does not cite any references or sources. ... Color vision is the capacity of an organism or machine to distinguish objects based on the wavelengths (or frequencies) of the light they reflect or emit. ... Color blindness in humans is the inability to perceive differences between some or all colors that other people can distinguish. ... Opponent colors based on experiment. ... ... Dichromacy in humans is a moderately severe color vision defect in which one of the three basic color mechanisms is absent or not functioning. ... A trichromat is an organism for which the perceptual effect of any arbitrarily chosen light from its visible spectrum can be matched by a mixture of no more than three different pure spectral lights. ... A tetrachromat is an organism for which the perceptual effect of any arbitrarily chosen light from its visible spectrum can be matched by a mixture of no more than four different pure spectral lights. ... This article or section does not cite its references or sources. ...

  Results from FactBites:
 
Optical spectrum (250 words)
The optical spectrum (visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye (see color for the sequence of colors).
Wavelengths in the range visible to the eye occupy most of the "optical window", a range of wavelengths that are easily transmitted through the Earth's atmosphere.
The term "optical spectrum" originally applied only to that region of the electromagnetic spectrum which is visible to the normal human eye, but is now considered to include all wavelengths between the shortest wavelengths of X-rays and the longest of radio.
Reading on Color & Light, Part I (1624 words)
The electromagnetic spectrum, which encompasses the visible region of light, extends from gamma rays with wave lengths of one hundredth of a nanometer to radio waves with wave lengths of one meter or greater.
Visible light is the range of wavelengths within the electromagnetic spectrum that the eye responds to.
The region of visible light in wavelengths shown as a linear arrangement (a) and as a circle (b) as conceived by Sir Isaac Newton.
  More results at FactBites »

 
 

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