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Aspect Ratio
The standard proportion in width to height for a computer monitor is 4:3, but many new displays have a wider format: 16:9 or 16:10, designed for viewing movies or HDTV in wide format. Note that a 17-inch wide-format panel has about the same vertical dimension and vertical pixel count as a normal 15-inch panel, so you get about 120 percent of the viewing area of a 15-inch panel. A 17-inch standard panel, however, has 130 percent of the viewing area of a standard 15-inch screen.
Bits Per Colour
Modern graphics hardware uses 8 bits per colour channel to represent a picture, or 24 bits total (8 bits for each of the red, green and blue channels). This yields around 16.78 million different colours, and is known as TrueColour. Monitors with 8 bits per colour can reproduce TrueColour images faithfully, but some cheaper models of monitor only have 6 bits per colour (18 bits total, able to reproduce 262,144 colours). Monitors with 6 bits per pixel have to use tricks such as dithering to trick the viewer into believing they can display more colours than they actually can. These tricks cannot perfectly replicate the full colour range, however, and can result in aberrations in images being displayed. If good colour reproduction if an important consideration for you, then you should avoid these cheaper 6 bits per colour displays in favour of ones that support 8 bits per colour.
Connections
The connection is how the monitor attaches to the computer. The connection can be either analogue or digital in nature. Digital is considered the preferred connection method today, with analogue being provided mainly for compatibility with older equipment.
Analogue connection
LCDs are digital devices, meaning that they are intended to work with digital signals. VGA is an analogue standard designed to work with the previous generation of CRT monitors. For a LCD monitor to support VGA it must convert the analogue VGA signal to digital, which is certain to result in some loss of image quality, which manifests itself as some apparent blurriness in the image. Analogue connectors are provided mainly for compatibility with legacy hardware, and are becoming less common.
Digital connection
Most modern PCs can output a digital image signal directly, usually using the DVI standard, but in some cases with HDMI or DisplayPort connectors. As LCDs are inherently digital, a digital signal will produce the best possible image quality with no distortion or blurriness caused by an unnecessary digital to analogue and back to digital conversion.
Contrast Ratio
A measure of the difference between the darkest colour a monitor can produce (black) and the brightest colour it can produce (white). In theory, the contrast ratio should ideally be infinite, but in practice this is impossible because most monitors produce a "black" that is in fact a very dark grey and the white is limited by how bright an image can be without dazzling the viewer. Manufacturers have tended to inflate their contrast ratio statistics, so be wary of manufacturer's claims regarding contrast ratio.
Display size
Display size is measured in inches, corner to corner across the diagonal, so a 17 inch monitor is 17 inches from its bottom left to its top right corner. This means that while bot ha standard and a widescreen 17 inch monitor may both have the same diagonal size, the two monitors will have different dimensions. The standard screen monitor will be taller, while the widescreen display will be wider.
Dot Pitch
Dot pitch (also known as line pitch or pixel pitch) is a specification for a computer display that describes the distance between dots (sub-pixels) of the same colour on the inside of a display screen.
Dot pitch can be measured in millimetres (where a lower figure indicates closer spacing), or Dots Per Inch (where a higher figure indicates closer spacing). Closer spacing generally produces a sharper image (as there are more pixels in a given area).
Luminance
Brightness; a measure of how much light a panel can produce. Luminance is expressed in either nits or candelas per square meter (cd/m2), both units are equivalent (1 nit = 1 cd/m2). A measurement of 200 to 250 nits is OK for most productivity tasks; 500 nits is better for TV and movies.
TFT Technology
Several similar but different display technologies fall under the category of TFT display, each with its own characteristics, advantages and drawbacks.
TN plus film
TN (Twisted Nematic) plus film is the most common technology used in TFT panels today. This is because it provides a good compromise between low cost and good response times. They do tend, however, to suffer from limited viewing angles. As you move away from the centre line of the monitor and start looking at it more side on, the colours become increasingly distorted. Colour reproduction in general tends not to be as good as other systems such as IPS
IPS
IPS (In-Plane Switching) is a technology intended to overcome the image quality problems inherent in TN + Film displays. They have much wider viewing angles and reproduce colour far more faithfully. They are less responsive than TN + Film displays, and are also considerably more expensive. This makes them well suited to professional image editing applications, but a poor choice for multimedia or gaming, as the slow response times make ghosting an issue.
MVA
MVA (Multi-domain Vertical Alignment) is a technology intended to combine the best elements of TN + Film and IPS systems. Modern MVA panels can offer wide viewing angles (second only to S-IPS technology), good black depth, good color reproduction and depth, and fast response times. There are several "next-generation" technologies based on MVA, including AU Optronics' P-MVA and A-MVA, as well as Chi Mei Optoelectronics' S-MVA.
PVA
PVA (patterned vertical alignment) and S-PVA (super patterned vertical alignment) are alternative versions of MVA technology offered by Samsung. Developed independently, they offer similar features to MVA, but with higher contrast ratios of up to 3000:1. Less expensive PVA panels often use dithering and FRC, while S-PVA panels all use at least 8 bits per colour. PVA and S-PVA offer good black depth and wide viewing angles and S-PVA also offers fast response times
Pixel-Response Rate
This refers to how quickly a pixel can change colours, measured in milliseconds (ms); the lower the milliseconds, the faster the pixels can change, reducing the ghosting or streaking effect you might see in a moving or changing image. In general, manufacturers' specifications rely on best-case scenarios; real-world performance is often considerably slower. A maximum response time of 12ms to 15ms across the spectrum is required for gaming or viewing television and movies without ghosting or streaking. Manufacturers have debuted LCDs with response rates as fast as 2ms, though don't expect such high performance in real world applications.
Portrait/Landscape Modes
Some LCDs can pivot so that the longer edge can go horizontal (landscape mode) or vertical (portrait mode). This feature can be useful for desktop publishing, Web surfing, and viewing large spreadsheets, but don't pay extra for it if you won't use it.
Resolution
Resolution of a measure of how many pixels a monitor has, expressed as pixels across by pixels up. For example, 1280 x 1024 describes a display with 1280 pixels across by 1024 pixels up, for a total of 1.3 million pixels. Make sure you are comfortable with an LCD's native resolution before you buy it. Remember, an LCD that scales its image to a non-native resolution will never look as good.
Viewing angle
The physical structure of LCD pixels can cause the brightness and even the colour of images to shift if you view them from an angle rather than facing the screen directly. Take manufacturer's specifications with a grain of salt and make your own observations if possible; viewing-angle issues become more critical as panel size increases.
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