Editing Computer monitor (section)

==Measurements of performance==
{{refimprove section|date=December 2020}}
The performance of a monitor is measured by the following parameters:

* Display geometry:
** [[Viewable image size]] – is usually measured diagonally, but the actual widths and heights are more informative since they are not affected by the aspect ratio in the same way. For CRTs, the viewable size is typically {{convert|1|in|mm|abbr=on}} smaller than the tube itself.
** [[Display aspect ratio|Aspect ratio]] – is the ratio of the horizontal length to the vertical length. Monitors usually have the aspect ratio [[4:3]], [[5:4]], [[16:10]] or [[16:9]].
** [[Radius of curvature]] (for [[Curved screen|curved monitors]]) – is the radius that a circle would have if it had the same curvature as the display. This value is typically given in millimeters, but expressed with the letter "R" instead of a unit (for example, a display with "3800R curvature" has a 3800{{nbsp}}mm radius of curvature.<ref>{{Cite web|url=https://pid.samsungdisplay.com/en/learning-center/white-papers/deep-dive-into-curved-displays#:~:text=When%20measuring%20curved%20monitors%2C%20the,the%20higher%20the%20monitor%27s%20curve.|title=Deep Dive into Curved Displays}}</ref>
* [[Display resolution]] is the number of distinct pixels in each dimension that can be displayed natively. For a given display size, maximum resolution is limited by dot pitch or DPI.
** [[Dot pitch]] represents the distance between the primary elements of the display, typically averaged across it in nonuniform displays. A related unit is pixel pitch, In LCDs, pixel pitch is the distance between the center of two adjacent pixels. In CRTs, pixel pitch is defined as the distance between subpixels of the same color. Dot pitch is the reciprocal of pixel density.
** [[Pixel density]] is a measure of how densely packed the pixels on a display are. In LCDs, pixel density is the number of pixels in one linear unit along the display, typically measured in pixels per inch (px/in or ppi).

* Color characteristics:
** [[Luminance]] – measured in candelas per square meter (cd/m{{sup|2}}, also called a ''nit'').
** [[Contrast ratio]] is the ratio of the luminosity of the brightest color (white) to that of the darkest color (black) that the monitor is capable of producing simultaneously. For example, a ratio of {{ratio|20,000:1}} means that the brightest shade (white) is 20,000 times brighter than its darkest shade (black). Dynamic contrast ratio is measured with the LCD backlight turned off. ANSI contrast is with both black and white simultaneously adjacent onscreen.
** [[Color depth]] – measured in bits per primary color or bits for all colors. Those with 10{{nbsp}}bpc (bits per channel) or more can display more shades of color (approximately 1 billion shades) than traditional 8{{nbsp}}bpc monitors (approximately 16.8&nbsp;million shades or colors), and can do so more precisely without having to resort to [[dithering]].
** [[Gamut]] – measured as coordinates in the [[CIE 1931 color space]]. The names [[sRGB]] or [[Adobe RGB color space|Adobe RGB]] are shorthand notations.
** [[Color difference|Color accuracy]] – measured in ΔE (delta-E); the lower the ΔE, the more accurate the color representation. A ΔE of below 1 is imperceptible to the human eye. A ΔE of 2{{ndash}}4 is considered good and requires a sensitive eye to spot the difference.
** [[Viewing angle]] is the maximum angle at which images on the monitor can be viewed, without subjectively excessive degradation to the image. It is measured in degrees horizontally and vertically.
* Input speed characteristics:
** [[Refresh rate]] is (in CRTs) the number of times in a second that the display is illuminated (the number of times a second a [[raster scan]] is completed). In LCDs it is the number of times the image can be changed per second, expressed in hertz (Hz). Determines the maximum number of frames per second (FPS) a monitor is capable of showing. Maximum refresh rate is limited by response time.
** [[Pixel response time|Response time]] is the time a pixel in a monitor takes to change between two shades. The particular shades depend on the test procedure, which differs between manufacturers. In general, lower numbers mean faster transitions and therefore fewer visible image artifacts such as ghosting. Grey to grey (GtG), measured in milliseconds (ms).
** [[Display lag|Input latency]] is the time it takes for a monitor to display an image after receiving it, typically measured in milliseconds (ms).
* [[Power consumption]] is measured in watts.

===Size===
{{Main|Display size}}
[[File:Computer screen dimensions.png|thumb|right|upright=1.2|The area, height and width of displays with identical diagonal measurements vary dependent on [[display aspect ratio|aspect ratio]].]]
On two-dimensional [[display device]]s such as computer monitors the display size or viewable image size is the actual amount of screen space that is available to display a [[picture]], video or working space, without obstruction from the bezel or other aspects of the unit's design. The main measurements for display devices are width, height, total area and the diagonal.

The size of a display is usually given by manufacturers diagonally, i.e. as the distance between two opposite screen corners. This method of measurement is inherited from the method used for the first generation of CRT television when picture tubes with circular faces were in common use. Being circular, it was the external diameter of the glass envelope that described their size. Since these circular tubes were used to display rectangular images, the diagonal measurement of the rectangular image was smaller than the diameter of the tube's face (due to the thickness of the glass). This method continued even when cathode-ray tubes were manufactured as rounded rectangles; it had the advantage of being a single number specifying the size and was not confusing when the aspect ratio was universally 4:3.

With the introduction of flat-panel technology, the diagonal measurement became the actual diagonal of the visible display. This meant that an eighteen-inch LCD had a larger viewable area than an eighteen-inch cathode-ray tube.

Estimation of monitor size by the distance between opposite corners does not take into account the [[display aspect ratio]], so that for example a 16:9 {{convert|21|in|cm|adj=on}} [[widescreen]] display has less area, than a {{convert|21|in|cm|adj=on}} 4:3 screen. The 4:3 screen has dimensions of {{convert|16.8|×|12.6|in|cm|abbr=on}} and an area {{convert|211|sqin|cm2|abbr=on}}, while the widescreen is {{convert|18.3|×|10.3|in|cm|abbr=on}}, {{convert|188|sqin|cm2|abbr=on}}.

===Aspect ratio===
{{Main|Display aspect ratio}}
Until about 2003, most computer monitors had a [[4:3]] [[Display aspect ratio|aspect ratio]] and some had [[5:4]]. Between 2003 and 2006, monitors with [[16:9]] and mostly [[16:10]] (8:5) aspect ratios became commonly available, first in laptops and later also in standalone monitors. Reasons for this transition included productive uses (i.e. [[field of view in video games]] and movie viewing) such as the word processor display of two standard letter pages side by side, as well as CAD displays of large-size drawings and application menus at the same time.<ref>NEMATech Computer Display Standards {{cite web |url=http://www.millertech.com/Technical_Specs.htm |title=NEMA Specifications |access-date=2011-04-29 |url-status=dead |archive-url=https://web.archive.org/web/20120302030131/http://www.millertech.com/Technical_Specs.htm |archive-date=2012-03-02 }}</ref><ref>{{cite web |archive-url=https://web.archive.org/web/20070315085244/http://www.necdisplay.com/support/css/monitortechguide/index05.htm |archive-date=2007-03-15 |url=http://www.necdisplay.com/support/css/monitortechguide/index05.htm |title=Introduction—Monitor Technology Guide |publisher=NEC Display Solutions }}</ref> In 2008 16:10 became the most common sold aspect ratio for [[LCD monitor]]s and the same year 16:10 was the mainstream standard for laptops and [[notebook computers]].<ref name="displaysearch1">{{cite web |url=http://www.displaysearch.com/cps/rde/xchg/SID-0A424DE8-28DF6E59/displaysearch/hs.xsl/070108_16by9_PR.asp |title=Product Planners and Marketers Must Act Before 16:9 Panels Replace Mainstream 16:10 and Monitor LCD Panels, New DisplaySearch Topical Report Advises |publisher=DisplaySearch |date=1 July 2008 |access-date=2011-05-20 |url-status=dead |archive-url=https://web.archive.org/web/20110721072242/http://www.displaysearch.com/cps/rde/xchg/SID-0A424DE8-28DF6E59/displaysearch/hs.xsl/070108_16by9_PR.asp |archive-date=2011-07-21 }}</ref>

In 2010, the computer industry started to move over from [[16:10]] to [[16:9]] because 16:9 was chosen to be the standard [[high-definition television]] display size, and because they were cheaper to manufacture.{{cn|date = November 2021}}

In 2011, non-widescreen displays with 4:3 aspect ratios were only being manufactured in small quantities. According to [[Samsung]], this was because the "Demand for the old 'Square monitors' has decreased rapidly over the last couple of years," and "I predict that by the end of 2011, production on all 4:3 or similar panels will be halted due to a lack of demand."<ref name="mybroadband1">{{cite web |url-status=live |url=http://mybroadband.co.za/news/hardware/17621-Widescreen-monitors-Where-did-1920x1200.html |title=Widescreen monitors: Where did 1920×1200 go? |archive-url=https://web.archive.org/web/20110113080158/http://mybroadband.co.za/news/hardware/17621-Widescreen-monitors-Where-did-1920x1200.html |archive-date=2011-01-13 |website=MyBroadband |date=10 January 2011 |first1=Jan |last1=Vermeulen |access-date=2011-12-24}}</ref>

===Resolution===
{{Main|Display resolution}}
The resolution for computer monitors has increased over time. From {{resx|280x192}} during the late 1970s, to {{resx|1024x768}} during the late 1990s. Since 2009, the most commonly sold resolution for computer monitors is {{resx|1920x1080}}, shared with the [[1080p]] of HDTV.<ref>[http://skinflint.co.uk/eu/?cat=monlcd19wide&sort=n&bpmax=&asuch=&v=e&plz=&dist=&filter=+update+list+&xf= Monitors/TFT 16:9/16:10 | Skinflint Price Comparison EU] {{webarchive|url=https://web.archive.org/web/20120426002744/http://skinflint.co.uk/eu/?cat=monlcd19wide&sort=n&bpmax=&asuch=&v=e&plz=&dist=&filter=+update+list+&xf=|date=26 April 2012}}. Skinflint.co.uk. Retrieved on 24 December 2011.</ref> Before 2013 mass market LCD monitors were limited to {{resx|2560x1600}} at {{convert|30|in|cm|abbr=on}}, excluding niche professional monitors. By 2015 most major display manufacturers had released {{resx|3840x2160}} ([[4K resolution|4K UHD]]) displays, and the first {{resx|7680x4320}} ([[8K resolution|8K]]) monitors had begun shipping.

===Gamut===
{{Main|Gamut}}
Every RGB monitor has its own [[color gamut]], bounded in [[chromaticity]] by a [[color triangle]]. Some of these triangles are smaller than the [[sRGB]] triangle, some are larger. Colors are typically encoded by 8 bits per primary color. The RGB value [255, 0, 0] represents red, but slightly different colors in different color spaces such as [[Adobe RGB color space|Adobe RGB]] and sRGB. Displaying sRGB-encoded data on wide-gamut devices can give an unrealistic result.<ref>{{cite web |url=http://regex.info/blog/photo-tech/color-spaces-page2 |title=Digital-Image Color Spaces, Page 2: Test Images |last=Friedl |first=Jeffrey |access-date=2018-12-10 |quote=See For Yourself The Effects of Misinterpreted Color Data }}</ref> The gamut is a property of the monitor; the image color space can be forwarded as [[Exif]] metadata in the picture. As long as the monitor gamut is wider than the color space gamut, correct display is possible, if the monitor is calibrated. A picture that uses colors that are outside the sRGB color space will display on an sRGB color space monitor with limitations.<ref>{{cite web |url=http://www.normankoren.com/color_management.html#Basics |title=Gamut mapping |last=Koren |first=Norman |access-date=2018-12-10 |quote=The rendering intent determines how colors are handled that are present in the source but out of gamut in the destination |archive-url=https://web.archive.org/web/20111221111848/http://www.normankoren.com/color_management.html#Basics |archive-date=2011-12-21 |url-status=dead }}</ref> Still today, many monitors that can display the sRGB color space are not factory nor user-calibrated to display it correctly. [[Color management]] is needed both in [[electronic publishing]] (via the Internet for display in browsers) and in [[desktop publishing]] targeted to print.