Editing Green (section)

=== Color vision and colorimetry ===
In optics, the [[perception]] of green is evoked by light having a spectrum dominated by energy with a [[wavelength]] of roughly 495–570&nbsp;[[Nanometre|nm]]. The sensitivity of the dark-adapted human eye is greatest at about 507&nbsp;nm, a blue-green color, while the light-adapted eye is most sensitive about 555&nbsp;nm, a yellow-green; these are the peak locations of the rod and cone (scotopic and photopic, respectively) [[luminosity function]]s.<ref>{{cite web
 | title = Human vision and color perception
 | website = Olympus Microscopy
 | department = Resource center
 | url = http://www.olympusmicro.com/primer/lightandcolor/humanvisionintro.html
 | access-date = 19 September 2007
 | archive-date = January 15, 2011
 | archive-url = https://web.archive.org/web/20110115040551/http://www.olympusmicro.com/primer/lightandcolor/humanvisionintro.html
 | url-status = dead
 }}</ref>

The perception of greenness (in opposition to redness forming one of the [[opponent process|opponent]] mechanisms in human [[color vision]]) is evoked by light which triggers the medium-wavelength ''M'' [[cone cell]]s in the eye more than the long-wavelength ''L'' cones. Light which triggers this greenness response more than the yellowness or blueness of the other color opponent mechanism is called green. A green light source typically has a spectral power distribution dominated by energy with a wavelength of roughly 487–570&nbsp;nm.{{efn|
More specifically, "blue green" 487–493&nbsp;[[Nanometre|nm]], "bluish green" 493–498&nbsp;nm, "green" 498–530&nbsp;nm, "yellowish green" 530–559&nbsp;nm, "yellow green" 559–570&nbsp;nm Kelly (1943).<ref>
{{cite journal
 | last1 = Kelly | first1 = Kenneth L.
 | year = 1943
 | title = Color designations for lights
 | journal = [[Journal of the Optical Society of America]]
 | volume = 33 | issue = 11| pages = 627–32
 | doi=10.1364/josa.33.000627
| bibcode = 1943JOSA...33..627K
 }}
</ref>
}}
[[File:RGB illumination.jpg|left|thumb|Red. green, blue ed are [[additive colors]]. All the colors seen are made by mixing them in different intensities.]]
Human eyes have color receptors known as cone cells, of which there are three types. In some cases, one is missing or faulty, which can cause [[color blind]]ness, including the common inability to distinguish red and yellow from green, known as [[deuteranopia]] or red-green color blindness.<ref name=brit>
{{cite encyclopedia
 |title=Color blindness
 |year=2002
 |encyclopedia=The New Encyclopædia Britannica
 |place=Chicago, IL
 |publisher=Encyclopædia Britannica Co.
 |isbn=0-85229-787-4
}}
</ref>
Green is restful to the eye. Studies show that a green environment can reduce fatigue.<ref>
{{cite journal
 |last=Laird |first=Donald A.
 |date=Sep 1933
 |title=Fatigue: Public enemy number one: What it is and how to fight it
 |journal=The American Journal of Nursing
 |volume=33 |issue=9 |pages=835–841
}}
</ref>

In the [[subtractive color]] system, used in painting and color printing, green is created by a combination of yellow and blue, or yellow and [[cyan]]; in the [[RGB color model]], used on television and computer screens, it is one of the [[additive primary colors]], along with red and blue, which are mixed in different combinations to create all other colors. On the [[HSV color space|HSV color wheel]], also known as the [[:File:RBG color wheel.svg|RGB color wheel]], the [[Complementary color|complement]] of green is [[magenta]]; that is, a color corresponding to an equal mixture of [[red]] and [[blue]] light (one of the [[purple]]s). On a traditional color wheel, based on subtractive color, the complementary color to green is considered to be red.<ref name=wheel>
{{cite web
 |title=Color wheel
 |year=2005
 |department=Glossary term
 |publisher=Sanford Corp.
 |url=http://www.sanford-artedventures.com/study/g_color_wheel.html
  |access-date=22 November 2007
 |archive-url = https://web.archive.org/web/20070928021215/http://www.sanford-artedventures.com/study/g_color_wheel.html
 |archive-date=28 September 2007
}}
</ref>

In additive color devices such as computer displays and televisions, one of the [[primary colors|primary]] light sources is typically a narrow-spectrum yellowish-green of dominant wavelength ≈550&nbsp;[[Nanometre|nm]]; this "green" primary is combined with an orangish-red "red" primary and a purplish-blue "blue" primary to produce any color in between – the RGB color model. A [[unique hues|unique green]] (green appearing neither yellowish nor bluish) is produced on such a device by mixing light from the green primary with some light from the blue primary.