contrast ratio for lcd monitors quotation

Unlike CRT monitors, LCD monitors display information well at only the resolution they are designed for, which is known as the native resolution. Digital displays address each individual pixel using a fixed matrix of horizontal and vertical dots. If you change the resolution settings, the LCD scales the image and the quality suffers. Native resolutions are typically:

When you look at an LCD monitor from an angle, the image can look dimmer or even disappear. Colors can also be misrepresented. To compensate for this problem, LCD monitor makers have designed wider viewing angles. (Do not confuse this with a widescreen display, which means the display is physically wider.) Manufacturers give a measure of viewing angle in degrees (a greater number of degrees is better). In general, look for between 120 and 170 degrees. Because manufacturers measure viewing angles differently, the best way to evaluate it is to test the display yourself. Check the angle from the top and bottom as well as the sides, bearing in mind how you will typically use the display.

This is a measurement of the amount of light the LCD monitor produces. It is given in nits or one candelas per square meter (cd/m2). One nit is equal to one cd/m2. Typical brightness ratings range from 250 to 350 cd/m2 for monitors that perform general-purpose tasks. For displaying movies, a brighter luminance rating such as 500 cd/m2 is desirable.

The contrast ratio rates the degree of difference of an LCD monitor"s ability to produce bright whites and the dark blacks. The figure is usually expressed as a ratio, for example, 500:1. Typically, contrast ratios range from 450:1 to 600:1, and they can be rated as high as 1000:1. Ratios more than 600:1, however, provide little improvement over lower ratios.

Unlike CRT monitors, LCD monitors have much more flexibility for positioning the screen the way you want it. LCD monitors can swivel, tilt up and down, and even rotate from landscape (with the horizontal plane longer than the vertical plane) to portrait mode (with the vertical plane longer than the horizontal plane). In addition, because they are lightweight and thin, most LCD monitors have built-in brackets for wall or arm mounting.

Besides the basic features, some LCD monitors have other conveniences such as integrated speakers, built-in Universal Serial Bus (USB) ports and anti-theft locks.

Contrast ratio - The difference in light intensity between white and black on an LCD display is called contrast ratio. The higher the contrast ratio, the easier it is to see details.

Ghosting - An effect of slower response times that cause blurring of images on an LCD monitor, it"s also known as latency. The effect is caused by voltage temporarily leaking from energized elements to neighboring, non-energized elements on the display.

Luminance - Also known as brightness, it is the level of light emitted by an LCD display. Luminance is measured in nits or candelas per square meter (cd/m2). One nit is equal to one cd/m2.

Stuck pixels - A pixel that is stuck either "on" or "off", meaning that it is always illuminated, unlit, or stuck on one color regardless of the image the LCD monitor displays can also be called a dead pixel.

Contrast ratio should be black and white. Taken at face value, it"s the ratio of the light level (luminance) the display produces when fed a white signal to the luminance when it"s fed a black signal. Unfortunately, it"s probably the most misused, inflated, and ultimately misleading specification used to describe HDTVs today.

At the 2009 Consumer Electronics Show, manufacturers quoted contrast ratio specs of 1,000,000:1 or 2,000,000:1 for upcoming Samsung and Sony for their current LED models. Those numbers sure do sound impressive, but what do they mean in the real world?

Very little. It"s true that in general, a higher contrast ratio can indicate that the display produces a deeper level of black, with all of the picture-quality benefits that brings--but then again it might not. Despite the million-to-one contrast ratios of the Samsung and Sony LED sets we reviewed, we observed better black-level performance in the Pioneer PRO-111FD. Pioneer doesn"t publish a contrast ratio spec for that television, but has claimed that its black levels are so deep as to be "immeasurable."

Manufacturers are free to use whatever method they like to "measure" the contrast ratio of their displays. The big numbers you see quoted most often are for "dynamic" contrast ratio, which takes into account changes the (usually LCD) display makes to adjust for fluctuations in the brightness of the content--namely, lowering the backlight in dark scenes and bringing it up in lighter ones. Then there"s the "native" contrast ratio number, always much smaller than the dynamic one, where the display doesn"t perform these adjustments. Both of these numbers are usually derived from the measurement of a full-white screen and a full-black screen (so-called full-on, full-off measurements), which is obviously not representative of actual program material.

A more-representative method is the ANSI contrast ratio measurement, which uses a checkerboard of eight white and eight black squares; the average luminance of the white and black squares determines the contrast ratio. Unfortunately, you"ll almost never see any manufacturer quote an ANSI number, since it"s usually tiny in comparison--a few hundred or few thousand or so to one.

We"re saying "most" and "usually" because there"s no standard way to measure the spec. We"ve heard tales of manufacturers pumping all of the wattage of a display into a single pixel and measuring that to determine the "white" section, or simply turning off the display to measure "black." More plausible, these numbers can simply be pulled out of thin air for competitive reasons--you don"t want to be the guy with the 500,000:1 TV when everybody else says 1,000,000:1, do you? You don"t have to, because nobody"s keeping track.

We have seen some signs of millions-fatigue in the CR spec game, however. At CES 2009, Samsung"s press material didn"t publish a number, instead using the phrase "mega-contrast" without any accompanying number. LG and Vizio use the same phrase, but did publish the numbers. We"ve already mentioned how Pioneer is avoiding numbers, and we hope more TV makers follow suit. When the numbers can be so inflated or simply made up, what"s the point?

That"s why we hope you"ll pay as little attention to published contrast ratio specs as we do. We rarely mention them in reviews, and when we have to refer to them in news or blog posts we try to put them in context, comparing last year"s specs from the same manufacturer with this year"s, for example. We"re still working on performing contrast ratio measurements ourselves as part of TV reviews, so look for that to happen this year. When it does, we doubt we"ll publish anything close to "one million."

The contrast ratio (CR) is a property of a display system, defined as the ratio of the luminance of the brightest shade (white) to that of the darkest shade (black) that the system is capable of producing. A high contrast ratio is a desired aspect of any display. It has similarities with dynamic range.

There is no official, standardized way to measure contrast ratio for a system or its parts, nor is there a standard for defining "Contrast Ratio" that is accepted by any standards organization so ratings provided by different manufacturers of display devices are not necessarily comparable to each other due to differences in method of measurement, operation, and unstated variables.projection screen or emitted by a cathode ray tube, and the only light seen in the room would come from the display device. With such a room, the contrast ratio of the image would be the same as the contrast ratio of the device. Real rooms reflect some of the light back to the displayed image, lowering the contrast ratio seen in the image.

Static contrast ratio is the luminosity ratio comparing the brightest and darkest shade the system is capable of producing simultaneously at any instant of time, while dynamic contrast ratio is the luminosity ratio comparing the brightest and darkest shade the system is capable of producing over time (while the picture is moving). Moving from a system that displays a static motionless image to a system that displays a dynamic, changing picture slightly complicates the definition of the contrast ratio, due to the need to take into account the extra temporal dimension to the measuring process.

Many display devices favor the use of the full on/full off method of measurement, as it cancels out the effect of the room and results in an ideal ratio. Equal proportions of light reflect from the display to the room and back in both "black" and "white" measurements, as long as the room stays the same. This will inflate the light levels of both measurements proportionally, leaving the black to white luminance ratio unaffected.

Some manufacturers have gone as far as using different device parameters for the three tests, even further inflating the calculated contrast ratio. With DLP projectors, one method to do this is to enable the clear sector of the color filter wheel for the "on" part and disable it for the "off" part

Another measure is the ANSI contrast, in which the measurement is done with a checker board patterned test image where the black and white luminosity values are measured simultaneously.

It is useful to note that the full on/full off method effectively measures the dynamic contrast ratio of a display, while the ANSI contrast measures the static contrast ratio.

An LCD technology is dynamic contrast (DC), also called advanced contrast ratio (ACR) and various other designations. When there is a need to display a dark image, a display that supports dynamic contrast underpowers the backlight lamp (or decreases the aperture of the projector"s lens using an iris), but proportionately amplifies the transmission through the LCD panel; this gives the benefit of realizing the potential static contrast ratio of the LCD panel in dark scenes when the image is watched in a dark room. The drawback is that if a dark scene contains small areas of superbright light, the resulting image will be over exposed.

The trick for the display is to determine how much of the highlights may be unnoticeably blown out in a given image under the given ambient lighting conditions.

It is also common to market only the dynamic contrast ratio capability of a display (when it is better than its static contrast ratio only on paper), which should not be directly compared to the static contrast ratio. A plasma display with a 4,000,000:1 static contrast ratio will show superior contrast to an LCD (with LED or CCFL backlight) with 30,000,000:1 dynamic and 20,000:1 static contrast ratio when the input signal contains a full range of brightnesses from 0 to 100% simultaneously. They will, however, be on par when input signal ranges only from 0 to 20% brightness.

This animated gif shows a rudimentary representation of how various backlight dimming technologies work on TV. Dimming technology can drastically affect the contrast ratio of the display.

In marketing literature, contrast ratios for emissive (as opposed to reflective) displays are always measured under the optimum condition of a room in total darkness. In typical viewing situations, the contrast ratio is significantly lower due to the reflection of light from the surface of the display, making it harder to distinguish between different devices with very high contrast ratios.luminance of the display, as well as the amount of light reflecting off the display.

There was a time when I used to lambast the meaninglessness of dynamic contrast ratio figures quoted in the latest TVs and monitors, but now I just give up...

Samsung has launched the "XL2370", a 23in 16:9 LED backlit monitor which it claims has a 5,000,000:1 dynamic contrast ratio. Let me say that again: 5,000,000:1. To put this in perspective, the eighth generation Pioneer Kuro - a set which revolutionised the HDTV landscape (as is still only bettered by its successor) - has a 16,000:1 contrast ratio. Sigh.

If you’re in the market for a new TV, projector, camera, or any other type of display, you should pay attention to the contrast ratio. But what does this measurement mean, and how do you know whether your display has good contrast?

While most displays have a contrast setting that the viewer can manually adjust, the ratio refers to the panel’s limitations—in other words, the largest possible difference between its lightest (white) and darkest (black) areas.

Contrast ratio is the measurement of the difference between a display"s maximum and minimum brightness; put another way, it"s the ratio between the brightest white and the darkest black. For example, a contrast ratio of 1,000:1 means that the brightest white image is 1,000 times brighter than the darkest black.

Generally, a higher contrast ratio is better since a display with a 100,000:1 ratio can produce darker black levels and more saturated colors than one with a 1,000:1 rating, thus achieving a more natural-looking image. That said, a bigger number isn"t always better, as you need to take external lighting conditions into account the lighting conditions and the type of display into account.

As previously mentioned, a higher contrast ratio has its benefits but isn’t the only thing you should consider. For example, a projector with a lower contrast ratio could provide an optimal viewing experience if you’ll be using it in a room with a lot of ambient light.

Contrast ratios can also vary significantly across different display types. While a transmissive digital projector may only have a contrast ratio of 200:1, many newer TVs are over 4,000:1. But even these figures don’t tell the whole story, as contrast ratios are dependent on the underlying technology and how they are measured.

When looking at a display’s contrast ratio, it’s important to understand the various ways in which they are measured. The actual ratio you see can be broken down into two different types: Static Contrast and Dynamic Contrast.

Static Contrast, otherwise known as “native” or “onscreen,” is a ratio comparing the brightest and darkest shade a display system is capable of producing at the same time. Since this ratio reflects the results from when the panel was made, industry experts typically consider this a more accurate representation of a display’s capabilities.

Dynamic Contrast offers a more theoretical range of a display’s contrast ratio, as it’s heavily dependent upon the screen’s underlying technology. Here, the range between the lightest areas of an all-white/light scene and the darkest areas of a black/dark scene is measured.

The problem with dynamic contrast measurements is that they are typically dishonest, as you’re unlikely to experience such a wide contrast range in the same scene. On top of this, manufacturers can manipulate contrast to make a scene lighter or darker using a display’s backlighting and firmware.

Unfortunately, there is no standardized measurement of contrast ratio. Particularly in the TV market, manufacturers can essentially inflate their ratings due to a combination of measurement and unstated variables. That said, most contrast ratios are measured using one of two methods:

Displays that measure with this method tend to register lower contrast ratios as ANSI contrast provides a more realistic measurement of the screen’s capability. However, since the test can include a room’s lighting conditions in its measurement, it needs to be performed in an ideal environment for the most accurate reading.

This method measures an all-white screen with an all-black screen and reflects equal proportions of light from the display to the room and back. It"s the preferred method for many manufacturers, as it cancels out exterior lighting conditions and results in an ideal (and thus higher) contrast ratio. Unfortunately, dynamic contrast specs are often misleading since they can be inflated and don"t indicate much about how an average image"s contrast will look.

The eye test is the best tool at your disposal — if a display’s black levels look washed out and gray, its contrast ratio probably isn’t high enough. However, there are other ways to ensure you’re not being misled:

Look for vendors that publish ANSI contrast specs, as this is a more accurate reflection of the display’s true contrast range. Unfortunately, many companies don’t disclose these figures, as ANSI readings tend to be much lower than Full On/Off, and it’s simply a better marketing strategy for these companies to focus on the latter.

Pay attention to backlighting technology.If you’re looking for a TV with a high contrast ratio, an OLED display will offer a better viewing experience than an LCD panel, as the OLED’s pixels don’t rely on a backlight and can display deeper blacks without a “blooming” effect.

Stick to the same manufacturer when making comparisons.Since every company arrives at its contrast ratios through different means, comparing displays produced by the same manufacturer is an excellent way to get consistent figures.

As it pertains to monitors, the contrast ratio is the ratio between the brightest white’s highest lumination level and the deepest black color the monitor is capable of producing. If a monitor has a high contrast ratio, it means it offers deeper shades of black, indicating a higher level of picture quality overall.

Contrast ratio is crucial for projector image quality. The higher the contrast ratio, the more detail viewers can see on the image projected. A higher contrast ratio also means more color subtlety is available, and more shading is visible.

Modern computer LCD monitors typically have a contrast ratio of between 1000:1 and 3000:1. A good gaming monitor may range toward the higher end of the spectrum, but use your eyes when considering a monitor you"re comfortable with and note that ambient light will affect what you"re seeing.

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As a first step, try using the calibration settings we recommend (provided we have reviewed your monitor). This will get good, basic contrast - meaning no additional contrast-enhancing settings - and with no loss of detail in dark portions of the image. You can find this information in the "Post Calibration" section of the review.

Contrast:Adjusting this will let you affect how much contrast the monitor has. We list a recommended setting with all of our reviews, but it"s almost always fine to just set this to the maximum. On rare occasions, gamma might be affected, leading to a loss of detail in highlights.

Local Dimming: The local dimming feature dims the backlight behind darker portions of the screen. It can deepen contrast, and it"s worth using when implemented well. It can introduce issues like light blooming off of light objects within dark areas, and when done especially poorly, can dim the entire image. We discuss local dimming in more detail here.

Backlight settings have a very minor impact on contrast, and so you should set it to whatever looks best in your viewing space. With LED Monitors, both white and black will become about equally brighter or dimmer when the backlight is adjusted, preserving the ratio of light to dark. With OLED monitors, adjusting the OLED light only increases the peak brightness; blacks are still perfectly black.

One frequently asked question is which is more important, a panel"s native contrast or contrast with local dimming? It"s a good question. The answer is a bit complicated, but basically, it depends. Unlike TVs, most monitors don"t have a local dimming feature. The few that do, generally speaking, don"t work very well. They usually have very small zone counts, and the algorithms can"t keep up with fast-paced motion, so the leading edge of a bright object in a dark scene ends up looking darker than the rest, and there"s a trail of light behind it.

Because of these issues with local dimming, it"s almost always more important to look at the native capabilities of a monitor instead of the contrast ratio with local dimming. Because most monitors have poor local dimming features, there"s usually not that much of a difference between the native contrast of the panel and the contrast with local dimming when tested with a checkerboard pattern. In fact, of the 23 monitors with local dimming that we"ve tested on our latest test bench, only 4 of them can improve contrast by 10% or more with our test pattern through local dimming.

There are different ways to measure contrast. We measure contrast with a checkerboard pattern and take the average black level from four squares, but some other review sites measure it differently, which can lead to a difference in posted numbers. Some of the other methods we"ve seen websites use include:

Full On/Off: Some websites measure the contrast using a full white screen, and a full black screen. This is generally considered a less accurate way to measure contrast, and it isn"t very realistic. Contrast measurements with local dimming tend to appear much better with this measurement technique, as it"s easy for any monitor with local dimming to turn the entire screen off at once.

Small Samples: Similar to the full-screen method, but instead of large slides, contrast is measured using small slides that only cover part of the screen. This method isn"t ideal either, as imperfect uniformity can significantly skew the results.

ANSI Checkerboard: The most generally accepted way to measure contrast; a checkerboard pattern very similar to ours is used, but with an asymmetric test pattern. The ANSI method measures the output in all 16 squares and averages the values for the white and black squares. It usually produces very similar results to our own.

Because of differences in measurement techniques, equipment used, and even differences between units, it"s extremely common for different websites to report different contrast measurements.

Monitors use different display technologies, each with advantages and disadvantages. Knowing which type of panel is used in your monitor can already give you a good indication of what to expect in terms of contrast ratio:

OLED: Very few OLED monitors exist, but they essentially have perfect contrast, as each pixel is self-emissive, the black level of black pixels is essentially zero.

Even within the same panel types, it"s normal for the contrast to vary a bit between units, even of the same model, due to manufacturing tolerances. Manufacturers used to provide the typical contrast ratio for each monitor, but recently, some brands, including LG, have started listing the minimum contrast ratio you could get. For IPS and TN panels, this difference usually isn"t very significant, and most people shouldn"t worry about it, but for VA panels, the variance between individual units and measurement techniques can be significant. For example, the LG 32GN600-B is advertised to have a typical contrast ratio of 3000:1, but according to LG, it could be as low as 1800:1 for some units. We measured a contrast ratio of 3248:1, almost double the minimum contrast for that model.

A monitor’s contrast ratio indicates the depth of blacks – a higher contrast ratio means deeper blacks – and, by extension, better picture quality. It’s a very important part of picture quality, so if you want something that looks good (particularly in a dark room), be sure to get a monitor that has good contrast.

There are a few things that can be done to improve contrast, but there are limits. As a good first step, look to our recommended picture settings (listed with every review), as those can help you get a good baseline. From there, you can enable or disable a few different settings that might help deepen blacks. Just remember that some of those settings will have other consequences on picture quality.

Additional features include a native resolution of 1024×768, Ø-Touch Auto-Tune function, OSD and power button lock functions, integrated power supply, and slim, compact design with a folding base for easy wall mounting. Easy on the environment and the budget, the VE155 15″ LCD display is an ideal choice for small home offices, corporate, education and government users.

On-Screen Menu ControlsAuto image adjust, contrast, brightness, input select, color adjust [9300K, 6500K (default)], R, G, B, information (mode, model number, serial number), manual image adjust (H. size, H. position, V. position, fine tune, sharpness), setup menu (language, resolution notice, OSD position, OSD timeout), memory recall

Now shipping with all the but the cheapest complete PCs are LCD monitors. Advances in display manufacturing and associated cost reductions with economies of scale have brought LCD monitors into the mainstream, shipping with budget systems that start at just £400. LCD monitors come in all shapes and sizes, have differing resolutions and inputs. The purpose of this HEXUS.help guide is to provide a basic understanding of how LCDs work, delineate their desirable characteristics, and to offer basic buying advice.

LCDs work in a relatively easy method to understand. Firstly, behind each LCD screen, where screens are defined by the number of pixels on a given panel, a light source is shone through from the behind to panel, through two panels of glass sandwiching the LCD, to your eyes. Each pixel on the LCD display has an array of liquid crystals (from whence the name arrives) whose molecules can be charged with a variable amount of voltage from electrodes over each subpixel (where each pixel is divided into red, blue and green filters), resulting in varying levels of light, from the source, passing through. Oversimplifying it somewhat, it"s the combination of subpixel voltage-switching and light source that make up the images you see.

LCD technology encompasses digital watches right up to ultra-high resolution displays. For the latter, each pixel can display one colour to another, activated by the variable voltage-switching from the pixels" transistors, detailed above. Faster switching between opposing colours (usually black-to-white), quoted in milliseconds, is usually a reasonable indicator of the panel"s effectiveness in displaying fast-moving images. The lower the ms time, the less time needed to redraw an image and, consequently, the lower the chance of ghosting or smearing when displaying fast-moving images. Manufacturers often have different methods of determining pixel response time, so it requires a little time investment on your part, to correctly determine whether the quoted figures between competing manufacturers is a consistent measure.

LCDs can be defined by the technology used to control the amount of refracted light (and by inference, colour) passing through from the source to your eyes. Broadly speaking, three technologies exist, and each has its own benefits and disadvantages. Twisted Nematic (TN) LCDs literally twist the liquid crystals in the display. The greater the twisting, controlled by the pixels" transistors, the less light passes through the LCD. Colours can then displayed in relation to just how much light is being passed through each pixel. This approach offers fast colour switching (response time) but usually at the cost of poor colour rendition for dark colours, especially blacks.

In-plane switching (IPS) uses two transistors per pixel, where the voltage is applied at each end of the horizontally-placed liquid crystal. The benefit is a better viewing angle, resulting from the alignment of the liquid crystal molecules. Vertical Alignment (VA) take the viewing angle benefits of IPS displays but only use a single transistor to do so. With no voltage applied by the pixel"s transistor to the naturally vertically-aligned liquid crystal, deep blacks are displayed, from the complete blocking off of light. Voltage application turns the liquid crystal from vertical to horizontal, matching the underlying layer and producing a white image. Colour consistency, therefore, is one of the hallmarks of VA displays.

The use of millions of transistors to create an electric field around liquid crystals can lead to the unwanted side-effect of dead/stuck-on (sub)pixels, arising from transistors not working correctly and thus not applying the correct voltage (or at all) to the LCs. LCD manufacturers generally claim that a non-perfect screen, that is, one with a small number of erroneously behaving pixels is a by-product of keeping LCD costs down. Recently, though, advances in manufacturing have allowed certain manufacturers to offer a zero bright-dot policy, where the display will be replaced if it ships with dead pixels.

LCDs are usually offered in a number of sizes, measured from corner to corner, with the display"s native resolution (number of vertical and horizontal pixels) and pixel pitch largely determining the optimum size. Pixel pitch, the space taken up by a single pixel, defined in miilimetres, usually ranges from 0.2mm-0.3mm. A lower pixel pitch adds in more pixels for a given size of display, thereby offering a sharper image. We"ve listed a number of LCD sizes and the native resolutions you"re likely to find with each.

WD=Widescreen The above table highlights a couple of interesting factors that need to be taken into account when considering an LCD monitor purchase. The jump from a 19" to 20" LCD is accompanied by a near-doubling of street price. Typically, 19" panels ship with an SXGA resolution and 20" screens with UXGA. The UXGA panels" pixel count is almost 50% higher than 19" models, leading to a lower pixel pitch and far greater pixel density. Consumers looking to invest in an LCD monitor for CAD modelling and video-editing purposes, for example, will be best served with panels with the greatest pixel density, so whilst 30-inch wide-aspect panels have the greatest screen estate from the selection above, the ultra-high WQXGA resolution ensures that they carry the lowest pixel pitch.

LCDs can also be defined in terms of brightness and contrast ratios. You"ll often see, for example, a particular panel quoted as having 500cd/m² (nits) brightness and a contrast of 1000:1. The brightness figure refers to the candela per square metre, with a higher figure offering greater brightness levels than a lower one. The contrast ratio is defined as the ratio difference in light intensity between the whitest white and deepest black. A higher nits figure and contrast ratio generally gives rise to a brighter screen with better colour representation.

Low-end LCD monitors tend to ship with analogue inputs, fed into the screen via an HD15 or DVI-I cable. Graphics cards natively output digital video signals, so having to convert between digital-to-analog at the source and back from analog-to-digital at the LCD"s end adds in the possibility of an inferior image than from a straight digital-to-digital (DVI-D) link, where digital inputs exist on higher-specified models. The degree of I.Q. inferiority between analogue and digital inputs is dependant upon the quality of the panel"s convertor, and it"s always preferable to use DVI-D for the cleanest, sharpest image quality. LCDs may well have both analogue and digital inputs, and switching between the two is usually just a matter of pressing a mode-select button.

LCD monitors may also carry a number of other inputs, including S-Video and composite. Again, it"s worth checking the exact specifications of each panel, to correctly determine the inputs on offer.

The current LCD monitor market is dominated by a handful of players who manufacture the displays themselves. Samsung, LG Philips, and AU are the most cited manufacturers, and virtually every retail LCD, be it Dell, Acer or HP, contains a panel from one of the trio. Advances in LCD design have lead to a lowering of cost, increases in panel performance, and lower instances of multi-defective pixels on a single display.

Year on year LCD panel manufacturers raise the bar with respect to response time, brightness and contrast ratio. A £300 20-inch UXGA panel today, then, is undoubtedly better than a similar £1,000 panel released 3 years ago. Each passing month brings the retail price of a particular type/size of display down a notch or two, and it is possible to buy a perfectly decent 19-inch DVI-capable LCD monitor for <£200. This is precisely why bulky, unwieldy CRTs are now a dying breed, and the low pixel response time, high brightness and contrast ratio figures of current LCD monitors make them a reasonable choice for fast-paced gaming, too.

A recent trend has been to introduce PC-orientated LCD monitors with wide-aspect displays, usually with a 16:10 viewing ratio, that work well as multimedia monitors for playing back content. We expect this trend to continue unabated throughout 2006. We also expect LCD manufacturers to further reduce black-to-white pixel response time with each new iteration of panel, making ghosting/smearing in fast-moving games a thing of the past.

Consumers looking for a LCD monitor to fit a particular budget are urged to check the panel"s response time, evaluate its brightness and contrast ratio in relation to its competition, and to make a note of its inputs. The maturity of the underlying technology and stiffness of competition is such that it is difficult to buy a bad LCD now. It always pays to do your research, though!

Aspect ratio is the relationship of the width of a video image compared to its height. The two most common aspect ratios are4:3, also known as 1.33:1 or fullscreen, and 16:9, also known as 1.78:1 or widescreen. (Larger aspect ratio formats are used in the motion picture industry.)

All the older TV’s and computer monitors you grew up with had the squarish 4:3 shape– 33% wider than it was high. These are often referred to as square monitors.  4:3 LCD monitors can display analog video signals that conform to NTSC and PAL standards. They are not capable of displaying HD (high-definition) video.

The 4:3 aspect ratio dates back to 1917, when the Society of Motion Picture Engineers adopted it as the standard format for film. In the 1930’s, the television industry adopted the same 4:3 standard. But in the mid-1950’s, the motion picture industry began developing several widescreen formats to improve their decreasing audience numbers. Television broadcasting stayed with the 4:3 standard, until the recent move to HDTV and 16:9 widescreen.

16:9 is the native aspect ratio of most high-definition widescreen LCD monitors and TV’s (16:9 and 16:10 are very similar). It is 78% wider than it is tall, and fully one-third wider than a 4:3 screen. 16:9 widescreen monitors are ideally suited to display HD video signals. Some models can also display SD (standard definition) video signals, but this will require some compromises, as you will read below.

Nearly all experts agree that in order to display optimal video images, it is critical to match the aspect ratio of the monitor to the aspect ratio of the camera (or other incoming video source). Below is a example of a 16:9 image on a 16:9 widescreen lcd monitor:

However, many cameras in the industrial, commercial, security, and law enforcement industries still utilize 4:3 CCD or CMOS imagers. Therefore, to display clear, undistorted video images, it is important to utilize monitors with the same 4:3 aspect ratio to match the cameras. Failure to do so will result in distorted images, as shown below.

Unfortunately, despite the continued widespread use of 4:3 cameras, LCD monitors with a 4:3 aspect ratio are getting harder and harder to find. Many manufacturers have abandoned them in favor of the newer 16:9 widescreens. TRU-Vu Monitors still offers a complete line of industrial-grade 4:3 aspect ratio LCD monitors. These range in size from 5.5″ to 19″ screens. They are available with standard, waterproof, steel or open frame enclosures. They can be touch screen,  sunlight readable, medical-grade, or optically bonded.

16:9 widescreen LCD monitors are the ideal complement to 16:9 format HD cameras. These are increasingly used in video conferencing, broadcast and medical applications. They display superb, distortion-free, high-definition images. TRU-Vu Monitors offers these in 7″, 10.1″, 13.3″, 15.6″, 17.3″, 18.5″ and 21.5″ to 65” LCD screen sizes, in standard, touch screen, sunlight readable, medical-grade, optically bonded and open frame configurations.

You must avoid video images which are stretched, chopped, squeezed, shrunk or distorted. Be sure to choose a LCD monitor with the correct aspect ratio (4:3 aspect ratio or 16:9 aspect ratio) that matches your camera or other incoming video signal.

A common claim on monitor spec sheets is an unfathomably high contrast ratio. Contrast ratio is the measurement of the ratio between the darkest black and the brightest white a display can produce. It sometimes reaches as high as 1,000,000:1, or in the case of the Samsung 200 Series monitors, “Mega Infinity Contrast Ratio” — yes, that’s a real term used by a real company. It’s as absurd as it sounds.

The best monitors we’ve reviewed barely break 1,000:1 when we measure them with a calibration tool. Televisions do better, but until desktop displays receive OLED technology, they’ll continue to lag behind. Monitors with a measured contrast ratio above 1,000:1 are the cream of the crop.

That’s static contrast ratio, as opposed to dynamic contrast ratio, which is what most manufacturers quote. Static indicates the widest distance between dark and light a monitor can project at a given brightness setting.

Dynamic contrast ratio uses a different measurement. Often, it involves measuring the absolute darkest black and the brightest white, even if each is measured at different display settings. The black reading might be taken with the display backlight nearly turned off, for example, while the white is taken with it at absolute maximum. Dynamic contrast ratio is not a standardized measurement so you can’t ever see all that contrast at once.

Manufacturers often only advertise the dynamic ratio. A third of the LCD monitors for sale right now on the popular retail site NewEgg are listed as having a 10,000:1 or higher contrast ratio. That’s almost 10 times higher than the best contrast ratio we’ve ever measured. 166 monitors (about 6 percent) list a contrast ratio of 10,000,000:1 — and all of them are from Acer or Asus.

Take, for example, the Asus ROG Swift PG27AQ. It’s a high-refresh-rate gaming monitor that’s certain to make games look smoother than a standard 60Hz panel. But you might be wondering how much nicer, exactly, so Asus prepared this handy graphic.

Below, for example, we see BenQ apply blur to supposedly simulate a lower refresh rate, and AOC use a simple contrast filter on a static image to simulate a feature that allegedly creates a more vivid image.

It’s not outright lying, but it is a clear exaggeration, and it’s certainly misleading. Especially for users who haven’t spent a lot of time looking at monitors in person, it’s becoming increasingly difficult to tell just how useful these features are.

One of the reasons manufacturers can get away with these hijinks is that the average user doesn’t have access to calibration tools that might reveal the truth. We use a DataColor Spyder4Elite in our testing and calibration process, and that’s a $300 piece of kit, which is about what most users are likely to spend on a monitor every few years. And it’s not a particularly fancy piece of equipment. The best calibration hardware costs thousands of dollars. Most people don’t have it, so they have no way to know if a monitor lives up to its claims.

But that’s no excuse. Misleading claims are bad for buyers and ultimately breed distrust. It’s easy to claim a high contrast ratio to make a product look better, and a normal buyer may not catch on at first. But eventually they’ll realize what’s up, and get fed up – perhaps so much so, that they no longer see the point in trying to buy a great monitor and resort to a budget model.

That would be a shame. A great monitor can make a PC way more fun, especially for those who like to watch movies and play games. As our own reviews have shown, there’s a big difference between the best and worst displays. Don’t get suckered into the hype. Do your research, and buy the display that truly excels.

Several manufacturers have introduced dynamic contrast controls to their monitors which are designed to improve black and white levels and contrast of the display on the fly, in certain conditions. It is supposed to help colours look more vivid and bright, text look sharper and enhance the extremes ends of the colour scale, making blacks deeper and whites brighter. This is achieved by adjusting the brightness of the backlighting rather than any adjustments at the matrix / panel level. The backlighting can be made less intensive in dark scenes, to make them even darker, and more intensive, up to the maximum, in bright scenes, to make them even brighter.

The official numbers for dynamic contrast are arrived at in the following manner: the level of white is measured at the maximum of backlight brightness and the level of black is measured at its minimum. So if the matrix has a specified contrast ratio of 1000:1 and the monitor’s electronics can automatically change the intensity of backlight brightness by 300%, the resulting dynamic contrast is 3000:1. Of course, the screen contrast – the ratio of white to black – is never higher than the monitor’s static specified contrast ratio at any given moment, but the level of black is not important for the eye in bright scenes and vice versa. That’s why the automatic brightness adjustment in movies is indeed helpful and creates an impression of a monitor with a greatly enhanced dynamic range.

The downside is that the brightness of the whole screen is changed at once. In scenes that contain both light and dark objects in equal measure, the monitor will just select some average brightness. Dynamic contrast doesn’t work well on dark scenes with a few small, but very bright objects (like a night street with lamp-posts) – the background is dark, and the monitor will lower brightness to a minimum, dimming the bright objects as a consequence. Ideally this kind of enhancement shouldn"t be used in office work since it can prove distracting or problematic for colour work. However, movies and sometimes gaming can offer some impressive improvements thanks to such technologies.

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While ppi is an important consideration, Tom Taylor, who is known as Tsquared and is a Major League Gaming champion, said it was not his primary concern when buying a display. He has six displays in the gaming lair he has created at his house and three standbys in a closet.

“Response time is the first thing I look at,” he said, referring to the time it takes for pixels to respond to the electrical impulses that change their color, which, in aggregate, creates a new image. “Gamers’ hand-eye coordination is twitch reflexes, so more than a 2-millisecond response time is a little delayed for us,” he said.

Also important for moving as well as still images is contrast ratio, which is the ratio between the display’s blackest black and its whitest white. A contrast ratio of 1,000:1 is respectable — 2,000:1 is stellar. Ignore the misleading “dynamic contrast ratio” manufacturers often promote, which can be millions to one. Display experts agree that it is artificially derived and misleading.

Closely related to contrast ratio is black level. “If you want a better movie or gaming experience, you’re going to want to look for a nice low black level,” said Art Marshall, product manager for professional and medical desktop displays at NEC. “When you’re watching ‘The Lord of Rings’ and what’s supposed to be black around the torch light is gray, it takes away from the effect.”

Manufacturers generally don’t volunteer the black level, but reviews on Web sites like Tom’s Hardware and the German site PRAD.de are only too happy to oblige. The industry says pitch black is zero nits, or candelas per square meter (cd/m2), which is nearly impossible to achieve in a display, so look for something less than 1 cd/m2.

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