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|Launched||October 1, 1992|
|Owned by||Turner Broadcasting System, Inc. (a Time Warner Company)|
|Picture format||480i (SDTV)
|Sister channel(s)||Boomerang, Adult Swim|
|DirecTV||Channel 296 (east coast feed)
Channel 297 (west coast feed)
|Dish Network||Channel 176|
|Available on most cable systems||Check local listings for channels|
[[Image:Original Cartoon Network logo.png|thumb|right|The original Cartoon Network logo used from October 1, 1992 to June 14, 2004. Still in use as a legal production card for Cartoon Network Studios, and as the 'teeth' in the Adult Swim 'skull' production card.]] Cartoon Network is a cable television network created by Turner Broadcasting which primarily shows animated programming. The original American channel began broadcasting on October 1, 1992 with the Bugs Bunny short Rhapsody Rabbit being its first-ever aired program. Cartoon Network originally served as a 24-hour outlet for classic animation properties from the Turner Broadcasting libraries and is mainly youth-oriented, but shares channel space with a late-night adult-oriented channel programming block called Adult Swim. Since 2003 however, Cartoon Network began airing a small amount of live-action programming, mostly movies.
In October 2008, Cartoon Network began running a West Coast feed, with programming airing three hours after it airs on the main feed.
- 1 History
- 2 Programming
- 3 Current programming blocks
- 4 Past programming blocks
- 5 Movies
- 6 Related projects
- 7 See also
- 8 References
- 9 External links
- 10 Physics of color
- 11 Color perception
- 12 Associations
- 13 Health effects
- 14 Measurement and reproduction of color
- 15 See also
- 16 References
- 17 External links and sources
By the end of the 1980s, Ted Turner's cable-TV conglomerate had acquired the MGM film library (which included the older catalog of pre-1948 color Warner Bros. cartoons), and its cable channel Turner Network Television had gained an audience with its film library. In 1990, it purchased animation studio Hanna-Barbera Productions and acquired its large library as well as most of the Ruby-Spears library. By October 1, 1992, Cartoon Network was created as an outlet for Turner's considerable library of animation, and the initial programming on the channel consisted exclusively of reruns of classic Warner Bros. (like Looney Tunes and Merrie Melodies), MGM (like Tom and Jerry and Droopy Dog), and Hanna-Barbera cartoons (like The Jetsons and The Flintstones), with many Hanna-Barbera TV cartoons like Wally Gator used as time fillers. Most of the short cartoons were aired in half-hour or hour-long packages, usually separated by character or studio—Down With Droopy D aired old Droopy Dog shorts, The Tom and Jerry Show presented the classic cat-and-mouse team, and Bugs and Daffy Tonight provided classic Looney Tunes shorts. The majority of the classic animation that was shown on Cartoon Network no longer airs, with the exception of Tom and Jerry, A Pup Named Scooby-Doo, Scooby-Doo, Where Are You! and The New Scooby-Doo Movies. thumb|left|Screencap from a 1995 bumper. Hanna-Barbera started production on The What-A-Cartoon! Show (also known as World-Premiere Toons and "What-A-Cartoon"), a series of creator-driven short cartoons that premiered on Cartoon Network in 1995. It was the network's third original series (the second was Space Ghost Coast to Coast and the first was The Moxy Show). The project was spearheaded by several Cartoon Network executives, plus The Ren and Stimpy Show creator John Kricfalusi (who was an advisor to the network at the time) and Fred Seibert (who was formerly one of the driving forces behind the Nicktoons, and would go on to produce the similar animation anthology series Oh, Yeah! Cartoons). The chief purpose of The What A Cartoon Show was to help Cartoon Network expand their library of exclusive programming and it introduced a number of new cartoon ideas. Only seven of them, however, were spun off into their own series runs. These eight series, Dexter's Laboratory, Johnny Bravo, Cow and Chicken, I Am Weasel, The Powerpuff Girls, Ed, Edd n Eddy, Courage the Cowardly Dog, and Mike, Lu & Og became the origins of the network's original cartoons, collectively known as Cartoon Cartoons.
Enter Time Warner
In 1996, the merger of Turner with Time Warner was complete. This consolidated ownership of all the WB cartoons, so now post-1948 releases were being shown on the network, leading up to a 2000 announcement that Cartoon Network would be the exclusive TV home of the classic Warner Bros. animated library. Newer animated productions by WB also started appearing on the network - mostly reruns of shows that had aired on Kids' WB, plus certain new programs such as Justice League.
In 2006, CN became the exclusive US outlet for the Pokémon anime - reruns and first-run, the latter hithereto appearing on Kids' WB, and the former off and on since 2002.
Cartoon Network's 10th anniversary
thumb|right|Scene from Cartoon Network's "10 Years in 60 Seconds" Bumper On October 1, 2002, Cartoon Network's 10th birthday, Cartoon Network aired a one-day special bumper acknowledging their 10th anniversary. The promo showed quick clips from shows, bumpers, and promos throughout Cartoon Network's history.
A new era
On June 14, 2004, Cartoon Network relaunched itself with a new logo and slogan, “This is Cartoon Network.” The first program ever aired on the relaunched Cartoon Network was Rescue Heroes. The bumps now featured 2D cartoon characters from their shows interacting in a CGI city composed of sets from their shows. By now, nearly all of Cartoon Network's classic cartoon programming had been relocated to its sister network Boomerang to make way for new programming, with the exception of a select few, such as Tom and Jerry, a longtime staple of the Turner networks. Within a few months, the network took off more shows from the 1990s (Dexter's Laboratory, The Powerpuff Girls, etc.) and put them on a 30 minute block called The Cartoon Cartoon Show. Some shows like Time Squad, Mike, Lu & Og, I Am Weasel and Sheep in the Big City were taken off the network completely.
Cartoon Network today
In the summer of 2006, Cartoon Network's slogan was a simplistic “Cartoon Network - Yes!,” as spoken by Fred Fredburger, a character on The Grim Adventures of Billy & Mandy. Before then, the network's original slogan, "the best place for cartoons", had remained the network's slogan for nearly five years. The network also used bumps featuring the cast of Camp Lazlo as stick puppets and characters in front of a red background.
The 2006-2007 campaign featured three different styles of bumps. The first style is "Lunchbox of Doom", featuring an assortment of show clips inside a CGI gothic lunchbox, a reference to an episode of The Grim Adventures of Billy and Mandy. The second is "VS.", comparing two cartoon characters. Their next style was a reprise of the 2004 CGI City look, using flat, dark colors.
Through 2007, Cartoon Network retained the image campaign that began in 2006, albeit a slightly refreshed version . On October 15, 2007, the channel began broadcasting in 1080i High Definition. In late 2007, the network look was revamped, and bumpers and station identification were themed to The Hives song "Fall is Just Something That Grown-Ups Invented", and aired for several months. Another bumper named "Ridiculously Short Cartoons" airs shorts edited from shows as if they lasted five or 10 seconds.
Cartoon Network announced at its 2008 Upfront that it is working on a new project called "Cartoonstitute", which is headed by animators Craig McCracken (as executive producer) and Rob Renzetti (as supervising producer). Both report to Rob Scorcher, who created the idea. The program will work in a way similar to What A Cartoon!, by creating at least 150 pieces of animation within 20 months.
Cartoon Network has also begun to air some imported Canadian programs from Teletoon:
- George of the Jungle (2007 TV series) (January 18, 2008)
- Bakugan Battle Brawlers (February 24, 2008)
- Chop Socky Chooks (March 7, 2008)
- Total Drama Island (June 5, 2008)
In April 2008, Cartoon Network played a one minute sign-off bumper, depicting a child's daily activities from sunrise to nighttime. In the end, it reads "Good Night. See you tomorrow!" before the Adult Swim program block began. It was their first sign-off bumper after 7 years of showing such a nightly block. This sign-off was later revised to match the network's new look. A white, faceless character paints on a parental advisory warning for Adult Swim. Warnings now also appear before programs rated TV-PG and higher airing in the daytime.
Beginning May 25, 2008, Cartoon Network has been airing animated shorts, called Wedgies, to fill in spots between two programs.
On July 14, 2008, the network took on a brand new look created by Tristan Eaton and Kidrobot. The background is white, and uses white, faceless characters resembling bowling pins which are based on the blank, do-it-yourself vinyl toys called Munny which Kidrobot creates. The character would often resolve into a Cartoon Network character, such as Chowder or Flapjack, or another color, keeping the same basic shape. Various commercial parodies were aired, also using Cartoon Network characters. From July 2008 to the start of October, Greg Cipes, Kevin's voice actor in Ben 10: Alien Force became the network's announcer. The programming blocks also were changed to fit in with this new look, with different Munny dolls (or a rainbow of color for Har Har Tharsdays) being used.
Current programming blocks
You Are Here
You Are Here premiered on October 3rd, 2008 at 8PM. The schedule after October 10th, consists of Ben 10: Alien Force at 8:00PM, The Secret Saturdays at 8:30PM and Star Wars: The Clone Wars, not to be confused with the Clone Wars shorts previously aired on Cartoon Network, at 9:00PM and 9:30PM
Adult Swim is Cartoon Network's adult sister network, which premiered on September 2, 2001 in the USA.
Originally a Sunday-only block that was rerun on Thursdays, Adult Swim now airs Mondays through Saturdays at 11:00 PM (E/P) and Sundays at 10:00 PM (E/P) with an encore airing at 2 a.m. every night and then ending with an hour of older shows on every night but Sunday. The block, programmed by Williams Street, plays American animated comedy series and shorts geared towards audiences 17 and older and a wide variety of mature anime series and Original video animations (OVA) intended for ages 18 and older.
On March 28, 2005, the programming block was spun-off as a separate entity from Cartoon Network for Nielsen Ratings purposes. On March 27, 2006, Adult Swim started airing a half-hour early at 10:30 PM Mondays through Thursdays (E/P), but due to the Friday block added on July 6, 2007, they dropped the extra 30 minutes on July 2, 2007, bringing it back to air at 11:00 PM-4:00 a.m.
Har Har Tharsdays
Har Har Tharsdays (formerly CN Thursday Nights) is a block of programming on Cartoon Network that started airing June 5, 2008. During this block, comedy shows are being aired from 8:00 p.m. to 10:00 p.m. The shows have brand new episodes. These television shows consist of Chowder, The Marvelous Misadventures of Flapjack, Total Drama Island, and Johnny Test. For the night of October 2nd, 2008, the block became "Star Star Starsdays" in honor of the premiere of Star Wars: The Clone Wars that was happening the next day. For October 7,2008, the block temporarily became "Scare Scare Scaresdays" for Halloween.
Wedgies are shorts that appear occasionally after a show or a movie, usually as a time filler. Some Wedgies include Nacho Bear, Big Baby, Calling Cat 22, and The Talented Mr. Bixby.
Dynamite Action Squad
The Dynamite Action Squad portion of Fried Dynamite is still concurrent. It airs on Saturday mornings, bringing action shows like Robot Boy.
Past programming blocks
Toonami ran from March 17, 1997 through September 20, 2008, making it the longest-running programming block in Cartoon Network's history. The block premiered masses of action-oriented cartoons and was hosted originally by a CGI rendition of Moltar (from Space Ghost Coast to Coast), who was eventually replaced with Tom.
Fried Dynamite premiered on August 31, 2007 on Cartoon Network (United States). Fried Dynamite is the Friday-Saturday block of cartoon shows, hosted by Blake Michael, which airs on every Friday night from 7pm-11pm and Saturday night from 7pm-9pm. It ended October 3, 2008.
Cartoon Cartoon Fridays, was launched on May 7, 1999 and last aired on May 2, 2003. Cartoon Cartoon Fridays was the Friday night version of "Cartoon Cartoons". This program block on Cartoon Network that showcased the channel's original cartoon series, with new episode premieres usually taking place in this block. The block was "hosted" by cartoon characters that were part of Cartoon Cartoons shows. The block aired between 7 p.m.-5 a.m., with the shows and segments repeating at least twice.
On February 23, 2007, Cartoon Network aired the last Fridays.
Miguzi was a cartoon block that premiered on April 19, 2004. This block was themed around Erin, a girl who finds refuge within the confines of a strange spaceship that is trapped underwater and inhabited by aquatic creatures. Not surprisingly, this lighter-toned action block was from Williams Street, the producers of late-night programming block Adult Swim and Toonami, a block of programming which Miguzi replaced in the weekday-afternoon timeslot. Miguzi changed its shows often.
As of June 2007, Miguzi is no longer on the Cartoon Network lineup and was replaced by Master Control, an interactive block.
Master Control was a viewer-arranged programming block on Cartoon Network which ran from September 24, 2007 to November 9, 2007. The website for the block offered viewers the chance to choose between one of three teams (Blastadons, Shadowmark, and Vikinators) and vote on which shows would air during the week. Various codes, given out during the block, allowed players to multiply their vote. The block had one thirty-minute timeslot on Mondays to Thursdays, while a two-hour block airs on Fridays. The block is similar in principle to Teletoon's "SpinCycle!" block. The final episode of Master Control aired Friday, November 9, 2007.
Saturday Video Entertainment System
The Saturday Video Entertainment System was a Toonami-like block of action animation airing Saturday nights from March 15, 2003 to April 10, 2004. SVES was packaged like a video game, with a Samus Aran-like character in bumps reminiscent of older arcade/SNES game design. This block was also designed by Williams Street.
The first preschool programming block on Cartoon Network in the United States was Small World, afterward Big Bag premiered on June 2, 1996. Big Bag featured animated shorts from around the world and live action Muppet scenes. Big Bag ended in September 1998.
The second block, Tickle U premiered on August 22, 2005. Pipoca, Henderson, and Place hosted the block. Tickle U stopped in September 2006.
Currently, Cartoon Network broadcasts preschool programs on weekday mornings, although there is no preschool specific block.
Saturday afternoon blocks
Cartoon Network has aired Saturday afternoon mini-marathon blocks throughout the years. One of the first blocks the network aired was Super Chunk. From 1992-2001, Super Chunk aired a three-hour marathon of shows from its library of programming, mostly classic shorts and older Hanna-Barbera shows.
After a short-lived revamp, Super Chunk was replaced with Cartoon Olio, which premiered on July 7, 2001 and last aired on June 1, 2002. The block aired marathons of Cartoon Cartoons franchises such as Dexter's Laboratory, Ed, Edd n Eddy, Johnny Bravo, Courage the Cowardly Dog, The Powerpuff Girls, Time Squad and Cow and Chicken. The block also aired marathons of Hanna-Barbera franchises such as The Flintstones, Scooby-Doo, and A Pup Named Scooby-Doo.
In 2004, the block was revamped yet again with the introduction of Cartoon Network Block Party. Unlike its predecessors, Cartoon Network Block Party aired new episodes of some of the shows they presented. It aired Saturday afternoon from 3pm-6pm (sometimes 3pm-5pm). It lasted from June 19, 2004 - January 22, 2005. This block aired Cartoon Cartoon franchises such as The Powerpuff Girls, Codename: Kids Next Door and The Grim Adventures of Billy & Mandy, and non-Cartoon Cartoon franchises such as The Cramp Twins, Foster's Home for Imaginary Friends, Code Lyoko, Hamtaro and Totally Spies, and shows from other networks such as MegaMan NT Warrior, Shaman King.
June Bugs was a yearly 48 hour marathon of Bugs Bunny cartoons which started on the first weekend in June 1996. In 2001, the marathon was intended to air nearly every Bugs Bunny cartoon ever made in chronological order, but Time Warner demanded to pull off 12 cartoons deemed "politically incorrect" by today's standards. However, with there being considerably less than 48 hours of shorts, it would repeat several times. June Bugs has occasionally aired on sister network Boomerang.
Last Bell was an afternoon block which aired 2:00pm to 5:00pm on weekdays, from August 2003 to June 11, 2004, airing franchises like A Pup Named Scooby-Doo, Dexter's Laboratory, The Powerpuff Girls, Ed, Edd n Eddy, The Grim Adventures of Billy & Mandy, Codename: Kids Next Door, and The Cramp Twins.
Summer @ Seven
Summer @ Seven was the name of the summer line up that premiered on June 4, 2007. New episodes were shown every Monday through Friday night at 7 pm along with Pokémon Diamond and Pearl. A new show called Storm Hawks premiered in Summer @ Seven. The block ended August 31 and was replaced by Hullabanew on September 3.
- Mondays: Storm Hawks
- Tuesdays: Code Lyoko
- Wednesdays: Camp Lazlo
- Thursdays: Class of 3000 in the first weeks, Ben 10 for the remainder.
- Fridays: Foster's Home for Imaginary Friends in the first weeks, My Gym Partner's a Monkey for the remainder.
HullabaNew was a month-long block of programming which began on September 3, 2007, and ran for the remainder of September. During the event, one show was featured during a week, with new episodes airing several days during that week.
- Week 1: Camp Lazlo (September 3-6)
- Week 2: Foster's Home for Imaginary Friends (September 10-13)
- Week 3: My Gym Partner's a Monkey (September 17-20)
- Week 4: Squirrel Boy (September 24-27)
Cartoon Network's Cartoon Theatre/Movie Madness
Movie Madness (formerly Cartoon Network's Cartoon Theatre) is a motion picture television series on Cartoon Network, featuring animated theatrical feature films, animated made-for-TV feature films, and films made for Cartoon Network. It originally ran once a week on Saturday nights, the feature film of each week would be regularly advertised on the network making it an anticipated special movie event. The block used a classical western style with a theatrical quality of feel in its bumpers, involving a realistic-looking old-time ticket machine and a freely drifting movie ticket on top of a wood desk accompanied by the voice of Don LaFontaine, the footage being used before and after commercial breaks and in commercials advertising the block itself. The amount of time Cartoon Theatre ran varied, and based solely on the amount of time the feature film ran, and would perhaps disagree with Cartoon Network's hour-by-hour schedule. To even out the block's time-frame, a sub-block titled Toon Extra, a block based on newspaper delivery, aired after Cartoon Theatre films showing one or more cartoons helping to add less than an extra hour of content to span out the perhaps uneven time slot, when the block was still called Cartoon Theatre. If Toon Extra didn't completely fill the time slot a few extra commercials may be aired, plus the occasional black-out for lesser amounts of unadded seconds. Since 2004, live-action films, regardless if they are cartoon-related (though most are), became part of Cartoon Network's library of movies.
16 made-for-TV movies have aired on Cartoon Network. Except for Party Wagon (which had been a pilot for a later scrapped series), these films are, in effect, movie-length special episodes of Cartoon Network series Dexter's Laboratory, Camp Lazlo, Codename: Kids Next Door, The Grim Adventures of Billy & Mandy, My Gym Partner's a Monkey, Teen Titans, Foster's Home for Imaginary Friends, Ed, Edd n Eddy, and Ben 10. Also among the original movies are Cartoon Network's first original live-action movies, Re-Animated, and Ben 10: Race Against Time. House of Bloo's and Home were pilot movies for Foster's Home for Imaginary Friends and Class of 3000, respectively.
- Dexter's Laboratory: Ego Trip (aired December 10, 1999)
- The Flintstones: On the Rocks (aired November 3, 2001)
- Party Wagon (aired February 27, 2004)
- Foster's Home for Imaginary Friends: House of Bloo's (aired August 13, 2004)
- Codename: Kids Next Door: Operation Z.E.R.O. (aired August 11, 2006)
- Teen Titans: Trouble in Tokyo (aired September 15, 2006)
- Class of 3000: Home (aired November 3, 2006)
- Foster's Home for Imaginary Friends: Good Wilt Hunting (aired November 23, 2006)
- Re-Animated (aired December 8, 2006)
- My Gym Partner's a Monkey: The Big Field Trip (aired January 14, 2007)
- Camp Lazlo: Where's Lazlo? (aired February 18, 2007)
- The Grim Adventures of Billy & Mandy: Billy & Mandy's Big Boogey Adventure (aired March 30, 2007)
- The Grim Adventures of Billy & Mandy: Wrath of the Spider Queen (aired July 6, 2007)
- Ben 10: Secret of the Omnitrix (aired August 10, 2007)
- Ben 10: Race Against Time (aired November 21, 2007)
- Codename: Kids Next Door: Operation: I.N.T.E.R.V.I.E.W.S. (aired January 21, 2008)
- My Gym Partner's a Monkey: Animal School Musical (aired May 25, 2008)
- The Secret Saturdays: The Kur Stone (October 3, 2008)
- Underfist: Halloween Bash (October 12, 2008) 
- Destination Imagination (November 27, 2008)
- Scooby-Doo: In The Beginning (2009)
- Ben 10: Alien Force The Movie (2009)
Flicks is a Sunday night block that airs both live action and animated movies aimed towards a family audience. These movies generally started as theatrical releases or were originally direct-to-video. The block began on June 22, 2008, with the CGI-animated movie The Ant Bully. Currently,Action Flicks serves as a spin-off.
Boomerang was originally a programming block on Cartoon Network aimed towards the generation of baby boomers. It originally aired for four hours every weekend. The block's start time jumped frequently, with the Saturday block moving to Saturday afternoons, then back to the early morning, and the Sunday block moving to Sunday evenings. Eventually, Boomerang was shortened by an hour, making the total airing time 2 hours each weekend instead of the original four hours.
Boomerang (both the programming block and the original spinoff channel that launched on April 1, 2000) followed a unique programming format - every week, cartoons produced during a certain year (and cartoons produced during years prior to that year) would be showcased. For example, if Boomerang was showcasing the year 1969, the viewer would more than likely see an episode of Scooby-Doo, Where Are You! or Dastardly and Muttley in Their Flying Machines.
When Cartoon Network still ran its CGI city look (see 2004-2006), a promo aired involving the Mayor of Townsville officially opening Movement Inc., a fictional recreational dome facility. Thus began Cartoon Network's still-running Get Animated promotion, a campaign encouraging children to get active, more importantly in outdoor areas. Created in part of the American government's goal for a more active, and generally healthier generation, other kids' channels generally aired similar promotions during this time (such as Nickelodeon's Go Healthy Challenge). Original promos involved many different cartoon characters, and real kids, enjoying physical activities inside the Animation Station. Once Cartoon Network scrapped their CGI city look the Animation Station promos were abandoned, but the Get Animated campaign still continued. Current promos still show cartoon characters playing alongside kids, though occasional sports celebrities (such as Freddy Adu) make appearances. Other promos show real kids who make great physically-related achievements, or cartoon characters explaining ways of getting active.
In 2007, Cartoon Network aired clips and interviews of chosen kids who focus on sports (like surfing, snowboarding, etc.) or other activities (like young comedians) who explain how many years they have been doing the activity, dreams for the future, and offering words of encouragement to the viewers. It generally features interviews of the child's friends, family and/or instructor, explaining how much the child has improved over the years and other comments about the child. These interviews still air today and are usually shown after some cartoons finish, before the next cartoon starts.
Cartoon Network Universe: FusionFall
- Rhapsody Rabbit (1946)
- Cartoon Network's 10th anniversary
- Cartoon Network
- Liu, Ed (2008-04-03). "PR: Cartoon Network Creates The Cartoonstitute". Toon Zone. TimeWarner. Retrieved 2008-04-05.
- "TRISTAN EATON for KIDROBOT & CARTOON NETWORK". Thunderblog. Thunderdog. 2008-07-21. Retrieved 2008-08-26.
- Maxwell Atoms (2008-09-20). "Talk to the Fist". Retrieved 2008-09-20.
Category:American television networks Category:Cartoon Network Category:Children's television Category:HD channels Category:Television channels and stations established in 1992 Category:TV channels with British versions Category:Turner Television networks Category:Time Warner
Color or colour is the visual perceptual property corresponding in humans to the categories called red, yellow, blue and others. Color derives from the spectrum of light (distribution of light energy versus wavelength) interacting in the eye with the spectral sensitivities of the light receptors. Color categories and physical specifications of color are also associated with objects, materials, light sources, etc., based on their physical properties such as light absorption, reflection, or emission spectra.
Typically, only features of the composition of light that are detectable by humans (wavelength spectrum from 400 nm to 700 nm, roughly) are included, thereby objectively relating the psychological phenomenon of color to its physical specification. Because perception of color stems from the varying sensitivity of different types of cone cells in the retina to different parts of the spectrum, colors may be defined and quantified by the degree to which they stimulate these cells. These physical or physiological quantifications of color, however, do not fully explain the psychophysical perception of color appearance.
The science of color is sometimes called chromatics. It includes the perception of color by the human eye and brain, the origin of color in materials, color theory in art, and the physics of electromagnetic radiation in the visible range (that is, what we commonly refer to simply as Light).
Physics of color
|color||wavelength interval||frequency interval|
|red||~ 700–630 nm||~ 430–480 THz|
|orange||~ 630–590 nm||~ 480–510 THz|
|yellow||~ 590–560 nm||~ 510–540 THz|
|green||~ 560–490 nm||~ 540–610 THz|
|blue||~ 490–450 nm||~ 610–670 THz|
|violet||~ 450–400 nm||~ 670–750 THz|
|Color||/nm||/1014 Hz||/104 cm−1||/eV||/kJ mol−1|
Electromagnetic radiation is characterized by its wavelength (or frequency) and its intensity. When the wavelength is within the visible spectrum (the range of wavelengths humans can perceive, approximately from 380 nm to 740 nm), it is known as "visible light".
Most light sources emit light at many different wavelengths; a source's spectrum is a distribution giving its intensity at each wavelength. Although the spectrum of light arriving at the eye from a given direction determines the color sensation in that direction, there are many more possible spectral combinations than color sensations. In fact, one may formally define a color as a class of spectra that give rise to the same color sensation, although such classes would vary widely among different species, and to a lesser extent among individuals within the same species. In each such class the members are called metamers of the color in question.
The familiar colors of the rainbow in the spectrum – named using the Latin word for appearance or apparition by Sir Isaac Newton in 1671 – include all those colors that can be produced by visible light of a single wavelength only, the pure spectral or monochromatic colors. The table at right shows approximate frequencies (in terahertz) and wavelengths (in nanometers) for various pure spectral colors. The wavelengths are measured in vacuum (see refraction).
The color table should not be interpreted as a definitive list – the pure spectral colors form a continuous spectrum, and how it is divided into distinct colors is a matter of culture, taste, and language. A common list identifies six main bands: red, orange, yellow, green, blue, and violet. Newton's conception included a seventh color, indigo, between blue and violet – but most people do not distinguish it, and most color scientists do not recognize it as a separate color; it is sometimes designated as wavelengths of 420–440 nm.
The intensity of a spectral color may alter its perception considerably; for example, a low-intensity orange-yellow is brown, and a low-intensity yellow-green is olive-green.
For discussion of non-spectral colors, see below.
Color of objects
The color of an object depends on both the physics of the object in its environment and the characteristics of the perceiving eye and brain. Physically, objects can be said to have the color of the light leaving their surfaces, which normally depends on the spectrum of the incident illumination and the reflectance properties of the surface, as well as potentially on the angles of illumination and viewing. Some objects not only reflect light, but also transmit light or emit light themselves (see below), which contribute to the color also. And a viewer's perception of the object's color depends not only on the spectrum of the light leaving its surface, but also on a host of contextual cues, so that the color tends to be perceived as relatively constant: that is, relatively independent of the lighting spectrum, viewing angle, etc. This effect is known as color constancy.
Some generalizations of the physics can be drawn, neglecting perceptual effects for now:
- Light arriving at an opaque surface is either reflected "specularly" (that is, in the manner of a mirror), scattered (that is, reflected with diffuse scattering), or absorbed – or some combination of these.
- Opaque objects that do not reflect specularly (which tend to have rough surfaces) have their color determined by which wavelengths of light they scatter more and which they scatter less (with the light that is not scattered being absorbed). If objects scatter all wavelengths, they appear white. If they absorb all wavelengths, they appear black.
- Opaque objects that specularly reflect light of different wavelengths with different efficiencies look like mirrors tinted with colors determined by those differences. An object that reflects some fraction of impinging light and absorbs the rest may look black but also be faintly reflective; examples are black objects coated with layers of enamel or lacquer.
- Objects that transmit light are either translucent (scattering the transmitted light) or transparent (not scattering the transmitted light). If they also absorb (or reflect) light of varying wavelengths differentially, they appear tinted with a color determined by the nature of that absorption (or that reflectance).
- Objects may emit light that they generate themselves, rather than merely reflecting or transmitting light. They may do so because of their elevated temperature (they are then said to be incandescent), as a result of certain chemical reactions (a phenomenon called chemoluminescence), or for other reasons (see the articles Phosphorescence and List of light sources).
- Objects may absorb light and then as a consequence emit light that has different properties. They are then called fluorescent (if light is emitted only while light is absorbed) or phosphorescent (if light is emitted even after light ceases to be absorbed; this term is also sometimes loosely applied to light emitted due to chemical reactions).
For further treatment of the color of objects, see structural color, below.
To summarize, the color of an object is a complex result of its surface properties, its transmission properties, and its emission properties, all of which factors contribute to the mix of wavelengths in the light leaving the surface of the object. The perceived color is then further conditioned by the nature of the ambient illumination, and by the color properties of other objects nearby, via the effect known as color constancy and via other characteristics of the perceiving eye and brain.
Development of theories of color vision
- Main article: Color theory
Although Aristotle and other ancient scientists had already written on the nature of light and color vision, it was not until Newton that light was identified as the source of the color sensation. In 1810, Goethe published his comprehensive Theory of Colors. In 1801 Thomas Young proposed his trichromatic theory, based on the observation that any color could be matched with a combination of three lights. This theory was later refined by James Clerk Maxwell and Hermann von Helmholtz. As Helmholtz puts it, "the principles of Newton's law of mixture were experimentally confirmed by Maxwell in 1856. Young's theory of color sensations, like so much else that this marvellous investigator achieved in advance of his time, remained unnoticed until Maxwell directed attention to it."
At the same time as Helmholtz, Ewald Hering developed the opponent process theory of color, noting that color blindness and afterimages typically come in opponent pairs (red-green, blue-yellow, and black-white). Ultimately these two theories were synthesized in 1957 by Hurvich and Jameson, who showed that retinal processing corresponds to the trichromatic theory, while processing at the level of the lateral geniculate nucleus corresponds to the opponent theory.
In 1931, an international group of experts known as the Commission Internationale d'Eclairage (CIE) developed a mathematical color model, which mapped out the space of observable colors and assigned a set of three numbers to each.
Color in the eye
The ability of the human eye to distinguish colors is based upon the varying sensitivity of different cells in the retina to light of different wavelengths. The retina contains three types of color receptor cells, or cones. One type, relatively distinct from the other two, is most responsive to light that we perceive as violet, with wavelengths around 420 nm. (Cones of this type are sometimes called short-wavelength cones, S cones, or, misleadingly, blue cones.) The other two types are closely related genetically and chemically. One of them (sometimes called long-wavelength cones, L cones, or, misleadingly, red cones) is most sensitive to light we perceive as yellowish-green, with wavelengths around 564 nm; the other type (sometimes called middle-wavelength cones, M cones, or, misleadingly, green cones) is most sensitive to light perceived as green, with wavelengths around 534 nm.
Light, no matter how complex its composition of wavelengths, is reduced to three color components by the eye. For each location in the visual field, the three types of cones yield three signals based on the extent to which each is stimulated. These values are sometimes called tristimulus values.
The response curve as a function of wavelength for each type of cone is illustrated above. Because the curves overlap, some tristimulus values do not occur for any incoming light combination. For example, it is not possible to stimulate only the mid-wavelength/"green" cones; the other cones will inevitably be stimulated to some degree at the same time. The set of all possible tristimulus values determines the human color space. It has been estimated that humans can distinguish roughly 10 million different colors.
The other type of light-sensitive cell in the eye, the rod, has a different response curve. In normal situations, when light is bright enough to strongly stimulate the cones, rods play virtually no role in vision at all. On the other hand, in dim light, the cones are understimulated leaving only the signal from the rods, resulting in a colorless response. (Furthermore, the rods are barely sensitive to light in the "red" range.) In certain conditions of intermediate illumination, the rod response and a weak cone response can together result in color discriminations not accounted for by cone responses alone.
Color in the brain
While the mechanisms of color vision at the level of the retina are well-described in terms of tristimulus values (see above), color processing after that point is organized differently. A dominant theory of color vision proposes that color information is transmitted out of the eye by three opponent processes, or opponent channels, each constructed from the raw output of the cones: a red-green channel, a blue-yellow channel and a black-white "luminance" channel. This theory has been supported by neurobiology, and accounts for the structure of our subjective color experience. Specifically, it explains why we cannot perceive a "reddish green" or "yellowish blue," and it predicts the color wheel: it is the collection of colors for which at least one of the two color channels measures a value at one of its extremes.
The exact nature of color perception beyond the processing already described, and indeed the status of color as a feature of the perceived world or rather as a feature of our perception of the world, is a matter of complex and continuing philosophical dispute (see qualia).
Nonstandard color perception
If one or more types of a person's color-sensing cones are missing or less responsive than normal to incoming light, that person can distinguish fewer colors and is said to be color deficient or color blind (though this latter term can be misleading; almost all color deficient individuals can distinguish at least some colors). Some kinds of color deficiency are caused by anomalies in the number or nature of cones in the retina. Others (like central or cortical achromatopsia) are caused by neural anomalies in those parts of the brain where visual processing takes place.
While most humans are trichromatic (having three types of color receptors), many animals, known as tetrachromats, have four types. These include some species of spiders, most marsupials, birds, reptiles, and many species of fish. Other species are sensitive to only two axes of color or do not perceive color at all; these are called dichromats and monochromats respectively. A distinction is made between retinal tetrachromacy (having four pigments in cone cells in the retina, compared to three in trichromats) and functional tetrachromacy (having the ability to make enhanced color discriminations based on that retinal difference). As many as half of all women, but only a small percentage of men, are retinal tetrachromats. The phenomenon arises when an individual receives two slightly different copies of the gene for either the medium- or long-wavelength cones, which are carried on the x-chromosome, accounting for the differences between genders. For some of these retinal tetrachromats, color discriminations are enhanced, making them functional tetrachromats.
In certain forms of synesthesia, perceiving letters and numbers (grapheme–color synesthesia) or hearing musical sounds (music–color synesthesia) will lead to the unusual additional experiences of seeing colors. Behavioral and functional neuroimaging experiments have demonstrated that these color experiences lead to changes in behavioral tasks and lead to increased activation of brain regions involved in color perception, thus demonstrating their reality, and similarity to real color percepts, albeit evoked through a non-standard route.
After exposure to strong light in their sensitivity range, photoreceptors of a given type become desensitized. For a few seconds after the light ceases, they will continue to signal less strongly than they otherwise would. Colors observed during that period will appear to lack the color component detected by the desensitized photoreceptors. This effect is responsible for the phenomenon of afterimages, in which the eye may continue to see a bright figure after looking away from it, but in a complementary color.
Afterimage effects have also been utilized by artists, including Vincent van Gogh.
There is an interesting phenomenon which occurs when an artist uses a limited color palette: the eye tends to compensate by seeing any grey or neutral color as the color which is missing from the color wheel. E.g., in a limited palette consisting of red, yellow, black and white, a mixture of yellow and black will appear as a variety of green, a mixture of red and black will appear as a variety of purple, and pure grey will appear bluish.
The trichromatric theory discussed above is strictly true only if the whole scene seen by the eye is of one and the same color, which of course is unrealistic. In reality, the brain compares the various colors in a scene, in order to eliminate the effects of the illumination. If a scene is illuminated with one light, and then with another, as long as the difference between the light sources stays within a reasonable range, the colors of the scene will nevertheless appear constant to us. This was studied by Edwin Land in the 1970s and led to his retinex theory of color constancy.
Colors vary in several different ways, including hue (red vs. orange vs. blue), saturation, brightness, and gloss. Some color words are derived from the name of an object of that color, such as "orange" or "salmon", while others are abstract, like "red".
Different cultures have different terms for colors, and may also assign some color names to slightly different parts of the spectrum: for instance, the Chinese character 青 (rendered as qīng in Mandarin and ao in Japanese) has a meaning that covers both blue and green; blue and green are traditionally considered shades of "青."
In the 1969 study Basic Color Terms: Their Universality and Evolution, Brent Berlin and Paul Kay describe a pattern in naming "basic" colors (like "red" but not "red-orange" or "dark red" or "blood red", which are "shades" of red). All languages that have two "basic" color names distinguish dark/cool colors from bright/warm colors. The next colors to be distinguished are usually red and then yellow or green. All languages with six "basic" colors include black, white, red, green, blue and yellow. The pattern holds up to a set of twelve: black, grey, white, pink, red, orange, yellow, green, blue, purple, brown, and azure (distinct from blue in Russian and Italian but not English).
Individual colors have a variety of cultural associations such as national colors (in general described in individual color articles and color symbolism). The field of color psychology attempts to identify the effects of color on human emotion and activity. Chromotherapy is a form of alternative medicine attributed to various Eastern traditions.
When the color spectrum of artificial lighting is mismatched to that of sunlight, material health effects may arise including increased incidence of headache. This phenomenon is often coupled with adverse effects of over-illumination, since many of the same interior spaces that have color mismatch also have higher light intensity than desirable for the task being conducted in that space.
Measurement and reproduction of color
Relation to spectral colors
Most light sources are mixtures of various wavelengths of light. However, many such sources can still have a spectral color insofar as the eye cannot distinguish them from monochromatic sources. For example, most computer displays reproduce the spectral color orange as a combination of red and green light; it appears orange because the red and green are mixed in the right proportions to allow the eye's red and green cones to respond the way they do to orange.
A useful concept in understanding the perceived color of a non-monochromatic light source is the dominant wavelength, which identifies the single wavelength of light which produces a sensation most similar to the light source. Dominant wavelength is roughly akin to hue.
Of course, there are many color perceptions that by definition cannot be pure spectral colors due to desaturation or because they are purples (mixtures of red and violet light, from opposite ends of the spectrum). Some examples of necessarily non-spectral colors are the achromatic colors (black, gray and white) and colors such as pink, tan, and magenta.
Two different light spectra which have the same effect on the three color receptors in the human eye will be perceived as the same color. This is exemplified by the white light that is emitted by fluorescent lamps, which typically has a spectrum consisting of a few narrow bands, while daylight has a continuous spectrum. The human eye cannot tell the difference between such light spectra just by looking into the light source, although reflected colors from objects can look different. (This is often exploited e.g. to make fruit or tomatoes look more brightly red in shops.)
Similarly, most human color perceptions can be generated by a mixture of three colors called primaries. This is used to reproduce color scenes in photography, printing, television and other media. There are a number of methods or color spaces for specifying a color in terms of three particular primary colors. Each method has its advantages and disadvantages depending on the particular application.
No mixture of colors, though, can produce a fully pure color perceived as completely identical to a spectral color, although one can get very close for the longer wavelengths, where the chromaticity diagram above has a nearly straight edge. For example, mixing green light (530 nm) and blue light (460 nm) produces cyan light that is slightly desaturated, because response of the red color receptor would be greater to the green and blue light in the mixture than it would be to a pure cyan light at 485 nm that has the same intensity as the mixture of blue and green.
Because of this, and because the primaries in color printing systems generally are not pure themselves, the colors reproduced are never perfectly saturated colors, and so spectral colors cannot be matched exactly. However, natural scenes rarely contain fully saturated colors, thus such scenes can usually be approximated well by these systems. The range of colors that can be reproduced with a given color reproduction system is called the gamut. The CIE chromaticity diagram can be used to describe the gamut.
Another problem with color reproduction systems is connected with the acquisition devices, like cameras or scanners. The characteristics of the color sensors in the devices are often very far from the characteristics of the receptors in the human eye. In effect, acquisition of colors that have some special, often very "jagged," spectra caused for example by unusual lighting of the photographed scene can be relatively poor.
Species that have color receptors different from humans, e.g. birds that may have four receptors, can differentiate some colors that look the same to a human. In such cases, a color reproduction system 'tuned' to a human with normal color vision may give very inaccurate results for the other observers.
The next problem is different color response of different devices. For color information stored and transferred in a digital form, color management technique based on ICC profiles attached to color data and to devices with different color response helps to avoid deformations of the reproduced colors. The technique works only for colors in gamut of the particular devices, e.g. it can still happen that your monitor is not able to show you real color of your goldfish even if your camera can receive and store the color information properly and vice versa.
Pigments and reflective media
Pigments are chemicals that selectively absorb and reflect different spectra of light. When a surface is painted with a pigment, light hitting the surface is reflected, minus some wavelengths. This subtraction of wavelengths produces the appearance of different colors. Most paints are a blend of several chemical pigments, intended to produce a reflection of a given color.
Pigment manufacturers assume the source light will be white, or of roughly equal intensity across the spectrum. If the light is not a pure white source (as in the case of nearly all forms of artificial lighting), the resulting spectrum will appear a slightly different color. Red paint, viewed under blue light, may appear black. Red paint is red because it reflects only the red components of the spectrum. Blue light, containing none of these, will create no reflection from red paint, creating the appearance of black.
Structural colors are colors caused by interference effects rather than by pigments. Color effects are produced when a material is scored with fine parallel lines, formed of a thin layer or of two or more parallel thin layers, or otherwise composed of microstructures on the scale of the color's wavelength. If the microstructures are spaced randomly, light of shorter wavelengths will be scattered preferentially to produce Tyndall effect colors: the blue of the sky, the luster of opals, and the blue of human irises. If the microstructures are aligned in arrays, for example the array of pits in a CD, they behave as a diffraction grating: the grating reflects different wavelengths in different directions due to interference phenomena, separating mixed "white" light into light of different wavelengths. If the structure is one or more thin layers then it will reflect some wavelengths and transmit others, depending on the layers' thickness.
Structural color is responsible for the blues and greens of the feathers of many birds (the blue jay, for example), as well as certain butterfly wings and beetle shells. Variations in the pattern's spacing often give rise to an iridescent effect, as seen in peacock feathers, soap bubbles, films of oil, and mother of pearl, because the reflected color depends upon the viewing angle. Numerous scientists have carried out research in butterfly wings and beetle shells, including Sir Isaac Newton and Robert Hooke. Since 1942, electron micrography, has been used, which has helped studies and practical products derrived from the, for eaxmple a range of "photonic" cosmetics using structural color.
- Colorfulness, chroma, or saturation: how "intense" or "concentrated" a color is; also known as chroma or purity.
- Hue: the color's direction from white, for example in a color wheel or chromaticity diagram.
- Shade: a color made darker by adding black.
- Tint: a color made lighter by adding white.
- Value, brightness, or lightness: how light or dark a color is.
|Wikimedia Commons has media related to Colors.|
- International Color Consortium
- International Commission on Illumination
- List of colors
- Neutral color
- Primary color
- Secondary color
- Tertiary color
- See American and British English spelling differences.
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- Why are things colored?
- Why Should Engineers and Scientists Be Worried About Color?