Plasma TVs come in two types: EDTV and HDTV. EDTVs typically have a native resolution of 852x480. 852x480 represents 852 pixels across (left to right) and 480 pixels down (top to bottom) on the screen surface. This is higher than standard TV, but is not HDTV resolution. Plasmas classified as HDTVs have a native resolution of 1024x768 or higher.

Check to see if a Plasma is an EDTV or an HDTV. Most Plasma Televisions are now HDTVs, but there are some exceptions in the bargain price range. If the Plasma TV you are considering has a native resolution of 1024x768, 1366x768, or 1920x1080, you are looking at a true HDTV.

Certain sizes of plasma TV screens are as unique to a company as a fingerprint, such as 43 inches (Pioneer only), 55 inches (Hitachi only), 61 inches (Pioneer only) and 63 inches (Samsung only). If you see one of these with another brand name on it and a higher price, you may simply be paying a premium for that brand, or there may actually be some added value, such as improved video processing and scaling.

Keep in mind that true HDTV resolution can't be found in plasma TVs smaller than 50 inches. There are two HDTV broadcast standards – 1920x1080 interlaced (1080i), and 1280x720 progressive (720p). So, in order for a plasma TV to be considered truly 'HD', it should have at least the same amount of pixels as a 720p signal, or more.

'HD' in smaller sizes of plasma means that there are more pixels than 'ED' plasma, but generally not as many as there are in a true HD display. So, you'll find that it's difficult to see any substantial difference in picture quality between these two types of plasma TVs, particularly when viewing an HDTV program.

When viewing a widescreen DVD, you may often be surprised to se that the less expensive EDTV plasma TV actually looks sharper than the more expensive HDTV plasma TV! That's because the image resolution of a widescreen DVD (nominally 704x480) is very close to the actual pixel count (852x480) in an EDTV plasma.

Now to address a few concerns about plasma: First of all, today's plasma TVs don't have the same problems with premature image aging (burn-in, burn-out) that plagued older plasma monitors and TVs. That's because the mix of gases used in the panels have been changed to improve longevity. You'll hear the figure '60,000 hours' thrown around; be conservative and figure half that, which is 30,000 hours.

30,000 hours is the equivalent of watching eight hours a day of television, seven days a week for 10 years. I don't watch that much television, but perhaps you do. Assuming you operate your plasma TV in the 'Normal' or 'Cinema' picture modes and don't play video games on it too often, you should be in fine shape for quite some time.

Other terms that defines your TV

Determine the right screen size based on the floor plan of your home-entertainment room. Plasma monitors are measured diagonally across the screen, just like any other television set. You can typically choose from the following sizes: 32", 40", 42", 46", 50", 61", or 63". Bigger is not always better, especially when you're buying a plasma display to serve as the focal point of a home entertainment center. To get the most out of your investment, remember what your mother always said about sitting too close to the TV-that it's no good for your eyes. For the optimal viewing experience, you need to maintain the right distance between your viewing area and your television screen.

The right distance depends on the size of your TV:

For 32 to 37-inch TVs, you should sit back 6 to 10 feet from the screen itself.

For 42 to 46-inch TVs, you'll need 10 to 14 feet between you and the screen.

50-inch plasma displays look best when viewed from 12 to 16 feet away.

You'll need at least 15 feet of space between you and a plasma screen that's larger than 60 inches.

In determining the appropriate size TV for you, you should also consider the space required to install the unit itself. When recessing a plasma display unit, allow at least 3 inches of open space at the top of the unit and adequate ventilation space-at least 2 inches-behind it as well. Remember, too, that most plasma displays do not have built-in speakers, so you'll need to allow space enough to attach speakers (if you're not using a separate surround-sound setup) on each side of the TV. These speakers usually measure between 3 and 6 inches apiece.

Scaling

Scaling is a process where the plasma's viideo processor will match the resolution of the incoming signal to its native resolution. Lower resolution signals will be upscaled, but the processor will downscale higher resolution signals so that they can be displayed at the TV's native resolution, such as with an EDTV plasma.

Poor scaling can result in artifacts, such as jagged edges and inconsistent detail. It must also be noted that results also depend on the quality of the incoming signal.

•Definition of the Term: Upscaling

•Definition of the Term: Pixel Density

Contrast Ratio

Contrast ratio, or the degree of variation of the whitest and darkest parts of the image, is a very important factor to note. If a Plasma TV has a low contrast ratio, dark images will look muddy and gray, while light images will look washed out.

A good contrast ratio on a plasma is 5,000:1 or higher. Anything less than 5,000:1, especially on a set that is 42-inches or larger, may not provide the optimum viewing experience.

•Definition of the Term: Contrast Ratio

•The Contrast Ratio Game

Brightness

Without sufficient brightness your image will look muddy and soft, even in a dark room. Viewing distance, screen size, and ambient room light will affect the need for more brightness capability.

A brightness rating listed as 550 cd/m2 or higher is good, however, don't get bogged down with the technical number listed, just make sure the screen is bright enough for your needs upon your own visual inspection.

Viewing Angle

Make sure you can view the image on the Plasma from the sides as well as the from the prime viewing area. Plasma TVs typically have a good side-to-side viewing angle, with many going as wide as 160 Degrees, or about 80 degrees from the center viewing spot.

If you find that the image begins to fade or becomes unviewable within 45 degrees from either side of the center viewing spot, then it may not be a good choice where you have a large group of viewers sitting in different parts of the room.

Tuner Considerations

Almost all Plasma TVs have built-in NTSC tuners and, since 2007, also have built-in HDTV tuners for over-the-air HDTV reception. Some also have QAM tuners, which allow viewing of unscrambled HD-cable signals without a cable box. However, some Plasmas are Monitors Only, which means that they require an external tuner to receive any and all television signals.

If you receive your HDTV programming via cable or satellite, instead of over-the-air, the need for a built-in tuner is negated as you will be using the settop boxes provided by your cable/satellite service to receive HDTV programming.

THE FACTS – LCD

There are a number of companies manufacturing both the LCD panels used in these TVs and the finished TVs themselves. In Japan, the clear market leader is Sharp Electronics, who offers a wide range of sizes from under 20 inches to 26-, 32-, 37-, and even 45-inch LCD TVs. In Korea, Samsung SDI and LG Philips produce large quantities of LCD panels in sizes as large as 55 inches, and Samsung, LG, and Philips all retail them as finished TVs.

In Japan, Hitachi, NEC, Kyocera, Sanyo, and Panasonic have all manufactured smaller LCD TV screens at one time or another. In China, a host of companies are cranking out LCD TV products including Chi Mei Optoelectronics, AUO, and Chungwha Picture Tube in sizes to 46 inches.

Your TV is going to come from one of these companies, but it's a little harder to tell exactly which one than it is with plasma. The LCD market goes through cycles of panel oversupply and undersupply quite frequently, and trading companies who wholesale to US retailers constantly shop around to get the best price for their latest models.

As with plasma, the companies who make the largest quantities of LCD TVs (Sharp, Samsung, and LG with partner Philips) typically have the best picture quality. You'll also see higher prices for these brands than you will with the dozens of 'who's that?' brands out there.

That doesn't mean the 'who's that' brands are to be avoided. A new player in the market, Kreisen, recently announced 37-inch and 40-inch LCD TVs with analog tuners that use LG and Samsung LCD panels, but at greatly discounted prices from those brands.

Unlike plasma TVs, all widescreen LCD TVs over 15 inches in size have true HD resolution (usually 1280x768 pixels, sometimes more). Bigger models starting at 46 inches and up actually have 1920x1080 pixel resolution, but they command quite a price premium at the moment.

LCD TVs don't suffer from 'burn-in' or 'burn-out' like plasma panels do. They can, however, have 'stuck' or dead pixels. The leading manufacturers have higher standards for defective pixels, so you can usually purchase from those companies with confidence that you won't see white, black, red, green, or blue dots on your TV programs that won't go away (and if you do, your warranty offers some protection).

Although plasma TVs can generate extremely bright images, they have an automatic brightness governing system to keep them from doing so with high luminance program material so as to avoid burn-in and premature phosphor aging. LCD TVs have no such braking system and will usually make a much brighter image on the showroom floor and in your home.

Because plasma TVs employ phosphors for imaging, they are susceptible to glare from indoor and outdoor light. LCD TVs don't have this problem; they create images by shuttering light through tiny color filters and generally handle annoying reflections from open windows or nearby lights with no difficulty.

What LCD TVs don't have is deep, rich black levels. On average, the level of 'black' measured on the best LCD TVs is about 10 times as high as that measured on the best plasma TVs. Also, colors on LCD TVs don't appear to be as rich (or even accurate) as a plasma TV. As a result, you will probably find that LCD TVs seem to look better under normal room lighting, but plasma TVs excel when the lights are turned down.

LCD TVs are expected to last between 50,000 to 60,000 hours, and that's usually the time it takes for the backlight to burn out. However, you should read the fine print in your owner's manual: Those life expectancy numbers are not for full brightness, but only 50% or even 25% of full panel brightness. (Tests have been done to confirm this.)

The upside is that LCD TVs are available in so many sizes that you can put them just about anywhere you'd wish in your house. I've used 15-inch and 17-inch sizes as HDTV displays in my downstairs bathroom each year during the Super Bowl!

LCD TVs, as a general rule, use less power than plasma (25% on average) and also weigh less in equivalent screen sizes (about 20% on average). And they are slightly thinner, too, although when you are talking about TVs that measure only 3" to 5" in thickness, who really wants to split hairs?

Th e Difference between Digital TV and HDTV

Although there are technically 18 different standards for digital TV broadcasting (all Digital TV tuners are required to decode all 18 standards), the practical application of DTV has come down to 3 standards. These standards are: 480p, 720p, and 1080i.

480p

If you have a progressive scan DVD player and TV, you are familiar with 480p (480 lines of resolution, scanned progressively). 480p is similar to the same resolution of standard broadcast TV (and is referred to as SDTV or Standard Definition Television), but the image is scanned progressively, rather than in alternate fields. 480p does provide an excellent picture (especially on smaller 20-27" screens). It is much more film-like than standard cable or even standard DVD output, but it only provides half the potential video quality of an HDTV picture, therefore its effectiveness is lost on larger screen sets.

Although 480p is part of the approved DTV broadcasting scheme, it is not HDTV. This standard was included as one of the DTV broadcasting standards to provide broadcasters the option of providing multiple channels of programming in the same bandwidth as a single HDTV signal. In other words, 480p is just more of what we already have with only a slight increase in image quality.

720p

720p (720 lines of resolution scanned progressively) is also a digital TV format, but it is also considered as one of the HDTV standards. As such, ABC and FOX use 720p as their HDTV broadcasting standard. Not only does 720p provide a very smooth, film-like image due to its progressive scan formula, but image detail is at least 30% sharper than 480p. As a result, 720p provides an acceptable image upgrade that is visible on both medium (32"- 37") size screens as well as larger screen sets. Also, even though 720p is considered high-definition, it takes up less bandwidth than 1080i, which is covered next.

1080i

1080i (1,080 lines of resolution scanned in alternate fields consisting of 540 lines each) is the most commonly used HDTV format, and has been adopted by PBS, NBC, CBS, and CW (as well as satellite programmers HDNet, TNT, Showtime, HBO, and other pay services) as their HDTV broadcast standard. Although there is still a debate as to whether it is that much better than 720p in the actual perception of the viewer, technically, 1080i provides the most detailed image of all the 18 approved DTV broadcast standards. On the one hand the visual impact of 1080i is lost on smaller screen sets (below 32").

However, the two drawbacks to 1080i are:

1. It takes up the most bandwidth of all the DTV broadcast formats.

2. It is an interlaced signal, which means that the displayed image is made up of lines that are scanned alternately instead of progressively as in 480p and 720p.

3. 1080i cannot be displayed in its native form on an LCD, Plasma, or DLP television, so those types of sets need to convert the 1080i signal to either 720p or 1080p in order to display the image on the TV screen.

In other words if you have a 1080p HDTV, a Flat Panel or DLP TV will deinterlace the 1080i signal and display it as a 1080p image. This essentially removes any visible scan lines present in the interlaced 1080i image, resulting in very smooth edges. By the same token, if you have a 720p HDTV, your TV will deinterlace and downscale the 1080i image to 720p for screen display.

LCD   VS   PLASMA

Plasma technology consists of hundreds of thousands of individual pixel cells, which allow electric pulses (stemming from electrodes) to excite rare natural gases-usually xenon and neon-causing them to glow and produce light. This light illuminates the proper balance of red, green, or blue phosphors contained in each cell to display the proper color sequence from the light. Each pixel cell is essentially an individual microscopic florescent light bulb, receiving instruction from software contained on the rear electrostatic silicon board. Look very closely at a plasma TV and you can actually see the individual pixel cell coloration of red, green, and blue bars. You can also see the black ribs which separate each.

Whether spread across a flat-panel screen or placed in the heart of a projector, all LCD displays come from the same technological background. A matrix of thin-film transistors (TFTs) supplies voltage to liquid-crystal-filled cells sandwiched between two sheets of glass. When hit with an electrical charge, the crystals untwist to an exact degree to filter white light generated by a lamp behind the screen (for flat-panel TVs) or one projecting through a small LCD chip (for projection TVs). LCD monitors reproduce colors through a process of subtraction: They block out particular color wavelengths from the spectrum of white light until they're left with just the right color. And, it's the intensity of light permitted to pass through this liquid-crystal matrix that enables LCD televisions to display images chock-full of colors-or gradations of them.

LED TVs are a new form of LCD Television. The panel on an LED TV is still an LCD TV panel and operates the with the same twisting crystals matrix. The backlight is the difference - changing from flourescent to LED (light emitting diode) based backlighting. See our complete coverage of LED TV articles and models here. 

PICTURE QUALITY CONSIDERATIONS

CONTRAST / BLACK LEVELS

Plasma technology has certainly achieved quite high contrast ratios, a measure of the blackest black compared to the whitest white. Many plasma display manufacturers boast a contrast ratio of 40,000:1 these days though our tests using a standardized ANSI checkerboard pattern have not proven these numbers out. Plasma displays achieve such impressive black levels by using internal algorithms to block the power to particular pixels in order to render a pixel "dark" or black. While this can limit a plasma television's gray scaling, it does produce exceptionally black blacks - depending on the manufactured plasma display element (i.e. glass). A plasma TV uses maximum power when it is producing full white. As a result, some 2nd tier manufactured brands of plasma TVs have an audible buzz or whining sound when displaying white or very light images.

LCD (liquid crystal diode) displays, by contrast, utilize electric charges to twist and untwist liquid crystals, which causes them to block light and, hence, emit blacks. The higher the voltage passing through the liquid crystals in a given pixel, the more fully those crystals untwist and effectively block light - all of which makes these pixels darker. As opposed to plasma, LCD TVs use the most power when displaying a very dark or black image. This is a difficult process, and despite recent improvements in LCD black levels, only the best LCD televisions have managed to come close to plasma technology in contrast ratio. The one continual drawback here for LCD is off axis viewing, when black levels consistently drop. We have noted some improvement from LCD manufacturers lately in off axis viewing contrast.

ADVANTAGE: Closer than a year ago, but still Plasma. LCD TV manufacturers have made great improvements in black levels and in many cases have nearly managed to match the contrast ratio of plasma TVs. However, Plasma displays still maintain a clear advantage in this category due to fading blacks when viewing LCDs from off axis. For scenes with a lot of dark and light images shown simultaneously - as with content originating from DVDs, video games, and NTSC TV signals - plasmas still consistently outperform LCD TVs.

COLOR ACCURACY

In plasma displays, each pixel contains red, green, and blue elements, which work in conjunction to create 16.77 million colors. Insofar as each pixel contains all the elements needed to produce every color in the spectrum, color information was more accurately reproduced with plasma technology than it was with other display technologies. The chromaticity coordinates were more accurate on most plasma displays. Though the color saturation resulting from the pixel design of plasma displays is remarkable, LCD technology has nearly caught plasma in gray scaling color accuracy. Plasma continues to exhibit more richness in color information and more natural coloration. Today, SMPTE color coordinates in top plasma displays still normally outperform those in LCDs, which tend toward oversaturation.

LCD TVs reproduce colors by manipulating light waves and subtracting colors from white light. This is an inherently difficult template for maintaining color accuracy and vibrancy - though most LCD TVs manage quite well. While color information benefits from the higher-than-average number of pixels per square inch found in LCD televisions (especially when compared to plasmas), LCDs are simply not as impressive as plasmas with similar pixel counts. LCDs however, produce a typically brighter picture. Greens sometimes look oversaturated and reds can run a bit warm, but in a room with lots of ambient light coming in from windows, an LCD TV would be my choice.

ADVANTAGE: Preference to plasma but depends upon room light, manufacturer and model. Plasma TV color richness and naturalness will prevail in rooms with lower to normal lighting. LCD TVs perform better in very brightly lit rooms due to their inherent anti glare technology and brightness.

VIEWING ANGLES

Plasma manufacturers have made much of their near perfect 180 degree viewing angles, which is about as good as horizontal and vertical viewing angles get. This owes to the fact that each pixel produces its own light, rather than light being spread across the screen from one central source. Hence, each pixel is more readily visible because its brightness is consistent with every other pixel on the screen. One consistent area of superiority of plasma viewing angles is demonstrated when viewing dark material content, especially DVDs. A Plasma display holds the black levels from off axis, while LCD TVs lose black level intensity/contrast more as the angle off axis increases. This usually occurs after around 45 degrees off center.

LCD TV manufacturers have done much to improve their displays' viewing angles. The substrate material on newer-generation LCD models by Sharp and Sony has helped to expand those units' viewing angles, though they still have some ground to cover before catching plasma. Expect the best LCD HDTVs to have around 120 degree viewing angles.

ADVANTAGE: Plasma

FUNCTIONAL CONSIDERATIONS

COMPUTER USE

Generally the performance should be about the same in terms of displaying the video image provided that the resolution of the plasma or LCD TV is 1080p or higher. Some plasma TVs still have 720p resolution and this would be a drawback to a defined static image.

Burn in is the second factor. Though plasma TVs have substantial anti-burn in technology built in these days, there is still some risk there.

ADVANTAGE: LCD

FAST-MOVING VIDEO PLAYBACK

Plasma technology gets the easy nod here because of their excellent performance with fast-moving images and high contrast levels. It's an inherent quality of the technology. There are still some 2nd tier plasma manufacturers whose plasma TVs display some phosphor lag, a drag time in scenes changing from bright to dark.

While the "response time" of LCD TVs has markedly improved in the last couple of years, they still suffer from a slight "trailer" effect, where the individual pixels are just slightly out of step with the image on the screen. During fast moving scenes, the most discerning eyes can detect this slight motion response lag. Motion lag may also be detected on LCD TVs when the camera pans from side to side sometimes appearing to stutter or jerk. This applies to both flourescent backlit LCDs and LED backed LCDs.

LCD TV manufaacturers have worked hard to overcome the motion lag issue. Last years models saw the introduction of 120Hz refresh rate (up from 60). This year many models were introduced with 240Hz refresh rate. This refresh rate has drastically improved the response time. However, it also introduces unwanted video information by sharpening the picture background information and taking out necessary blur. This may seem like a positive, but with 90% of your viewing material, it is not. Depending upon the manufacturer, we advise turning off the 120Hz or 240Hz feature with all but live sports programming. See our full article about 120Hz/240Hz refresh rate here.

HIGH ALTITUDE

There is a reason LCD flat panels are the preferred visual display units for use on airplanes: LCD TVs aren't affected by increases or decreases in air pressure. Their performance is consistent regardless of the altitude at which they're utilized.

This is not the case for a plasma. The display element in plasma TVs is actually a glass substrate envelope with rare natural gases compressed therein. So, at high altitudes (6,500 feet and above), an air-pressure differential emerges, which causes plasma displays to emit a buzzing sound due to the lower air pressure. This noise can sound rather like the humming of an old neon sign. NEC has been effective in producing several plasma models that are rated to 9,500 feet.

ADVANTAGE: LCD, at 6,500 feet and higher.

LONGEVITY

LCD television manufacturers claim that their displays last, on average, 60,000. In fact, an LCD TV will last as long as its backlight does. Since this is nothing more than light passing through a prismatic substrate, there is little to wear out in an LCD TV except the backlighting. However, one nasty little known fact about LCD technology is that as the flourescent backlight ages it can change colors slightly (think of florescent bulbs in office lighting). When this occurs the white balance of the entire LCD TV will be thrown for a loop and the user will need to re-calibrate the TV. Some of the early purchasers of larger LCD screens will be learning this tidbit in a couple of years. From our research, flourescent bulb backlighting in LCDs cannot be replaced cost effectively. LED backlit LCDs provide a longer lasting stability, with little to no degradation in white balance over time.

Plasma TVs, on the other hand, utilize slight electric currents to excite a combination of noble gases (i.e., argon, neon, xenon), which glow red, blue, and/or green. This is an essentially active phenomenon, so the phosphoric elements in plasma displays fade over time. Many manufacturers state a new half life of 60,000 hours. While I am skeptical of this spec, I do believe strides have been made to nearly even the playing field with LCD. At half life, the phosphors in a plasma screen will glow half as brightly as they did when the set was new. There is no way to replace these gases; the TV simply continues to grow dimmer with use.

ADVANTAGE: Even Some manufacturers of both plasma and LCD state up to 100,000 hours now. At 4 hours per day that's 68 years of use. Where do they get these specs??

SCREEN BURN IN

LCD technology is not prone to screen "burn-in" or "ghosting" (premature aging of pixel cells) due to the nature of the technologies "twisting crystals."

With plasma, static images will begin to "burn-in," or permanently etch the color being displayed into the glass display element. The time it takes for this to occur depends greatly on the anti burn-in technology of the manufacturer. Recent improvements by plasma manufacturers have certainly extended the time it takes to burn in a plasma pixel cell. In the past I was concerned to place a DVD on pause 15 minutes. Now, many of the enhancements such as better green phosphor material, and motion adaptive anti burn-in technology are greatly reducing the risk of burn in. It's gotten so much better that I don't even worry about it anymore. In a new model plasma from any top tier manufacturer I would put "ghosting" estimates at an hour or more now (Ghosting can be "washed" out by displaying static gray material). Permanent burn-in I would put at more than 10 hours.

ADVANTAGE: LCD, though not as much a concern as it was a year ago.

OTEHR CONSIDERATIONS

PRODUCTION SIZE AND COST

All television measurements are stated in inches and are for diagonal measurement of the screen from corner to corner - not including framing.

Both plasma and LCD TVs are becoming more readily available in larger sizes though plasma still leads the size battle by a great margin. Pioneer and LG produce 61" plasma sizes while Panasonic has a readily available 65" model. Though it is not being imported into the U.S. yet, Samsung has produced a gigantic plasma of 100 inches. Though such mammoth monitors are expensive, they exhibit none of the "kinks" one might expect with such large displays. In other words, even the largest plasma displays are reliable. Large plasma displays will consume power - try 675 watts for a 65 "display compared to around 330 watts for a 42" plasma.

ADVANTAGE: Plasma, though the playing field is leveling. Even though production costs and retail prices have come down for both technologies, plasma still has the edge as far as production cost and capacity go.

POWER CONSUMPTION

Because LCDs use florescent backlighting to produce images, they require substantially less power to operate than plasmas do. LCD TVs consume about half the power that plasma TVs consume. The reason: Plasmas use a lot of electricity to light each and every pixel you see on a screen - even the dark ones. Though plasma manufacturers have improved voltage consumption requirements a plasma TV will consume around a third more power for the same size display.

ADVANTAGE: LCD

PRICE AND VALUE

Plasma TVs have generally enjoyed lower pricing per size vs. LCD TVs. While LCDs have nearly caught up with plasma in the 42" size, plasma still dominates in the larger size ranges. When comparing comparable Tier 1 Quality LCD with Tier 1 Plasma, the larger the size, the more the price savings by purchasing plasma. In the 46" size range a plasma currently sells for a 30% to 40% discount, while a 58" plasma may yield between 40% to 50% discount savings. Resolution is no longer an issue due to the fact that most all TVs 46" and larger are full HD 1920 X 1080 (1080p) resolution.

Our value ratings continue to be reason that plasma TVs generally receive higher marks in our overall TV ratings. See the full Comparison Ratings Chart here.

ADVANTAGE: Plasma, especially in larger size TVs.