As you stand in front of a wall of televisions at your local department store, plasma and LCD televisions may seem identical, but the similarities end once you look past the thin form factor and big screens.

HOW THEY WORK

Plasma televisions use a sheet of miniscule individual plasma cells that create a picture when an electrical charge is applied.

LCD televisions, on the other hand, use liquid crystal compressed between two glass plates; an image is created when electricity is applied to these crystals.

LED televisions use liquid crystal, but unlike regular LCD televisions they use a backlight made of hundreds of LEDs (light-emitting diodes) instead of a fluorescent lamp. The LEDs can be evenly distributed around the back of the television’s panel or situated in the edges of the screen to create a very thin display chassis.

How well an image is displayed on a television panel — whether it is a Blu-ray movie, an HDTV broadcast or a high-definition video game — depends on a television’s display technology and its image processing capabilities.

CONTRAST RATIO

A television’s contrast ratio represents its ability to show detail in high contrast areas of the screen, in the form of minute gradations of colour and blacks or whites. For example, a panel with a low contrast ratio will struggle to show the higher or lower extremes of an image. basically, this means detail will be lost in bright areas as well as in dark scenes. In a Blu-ray movie, the loss of detail in dark scenes will quickly become apparent such as a movie like Batman Begins.

Most manufacturers increase the contrast capabilities of their screens by dynamically altering backlight brightness. This allows extra detail to be shown in dark scenes and can be a life-saver for a panel with a low static contrast ratio. Some manufacturers have taken their estimations of this dynamic contrast ratio to excess, rating their screens at contrast ratios of 1,000,000:1 — and even higher. While these figures demonstrate the advantages of dynamic contrast ratio alteration, they don’t need to be a big factor in your buying decision.

It is generally accepted that plasma televisions have better contrast ratios than LCD panels, due to the fact that a plasma television can completely deactivate the light source for individual segments of the screen. This means sections of the screen can be completely dark while others are displaying bright colour, unlike a traditional LCD screen which has a single backlight array that can only alter brightness levels for the entire screen.

The latest LED backlight technology allows the television to individually control backlight segments. This technology allows for contrast ratios similar to those produced by plasma television panels. However, edge-lit LED televisions — usually available in an ultra-slim form factor — will have lower dynamic contrast ratios than the backlit LED models so be sure to check this detail before you purchase.

VIEWING ANGLE

The narrower a television’s quoted viewing angle is, the smaller the range in which it produces a ‘perfect’ image with no loss of contrast or colour. Many manufacturers quote an unrealistically high viewing angle — close to a full 180 degrees in some instances — but the best way to test this is to test the screens in person.

A wide viewing angle is important if the television will be placed in a large living area or will be regularly watched by multiple people simultaneously — most of us will have family and friends around to watch the TV at some point!

In general, plasma televisions have better viewing angles than LCD and LED TVs, with their images remaining solid and colourful at wide viewing angles while LCDs suffer from colour shift and loss of brightness. This is not always the case, though, so it is best to compare panels directly against each other if possible. LED televisions have superior viewing angles compared to LCDs due to their decentralised backlight distribution.

COLOUR

Colour is an aspect that is largely independent of the television’s type, relying on the processing technology independent to each manufacturer and specific screen model. However, it is important to note that plasma televisions can in theory produce brighter colours overall. LED-lit televisions using either a white or RGB LED backlight also offer a larger colour gamut than traditional LCD screens, due to an improved brightness source. Colour accuracy can be adjusted on almost all screens, whether you choose a plasma, LED or LCD TV.

MOTION

There is much discussion as to whether plasma or LCD screens are better at handling fast motion — sports or action movies are a great example of video footage that moves across the screen at a fast rate. A plasma screen’s ability to refresh each individual cell at a much faster rate than an LCD pixel refresh means that plasma panels have an inherent advantage in displaying fast motion free of blur and jitter.

New LCD screens can now update the image displayed 100 times per second — the often touted ‘100Hz’ technology, which is double the standard 50Hz rate. This removes significant amounts of jitter from the LCD screen’s image, resulting in a smoother and more visually pleasing picture. It is a great feature when watching sports where both the players and camera move often. The next generation of this technology doubles the refresh rate again to 200Hz but screens with this technology is not incorporated into all LCD TVs on the market.

At present, our expereince suggest that plasma TVs are still superior in handling fast motion, but the motion-handling of LCD TVs has improved greatly over the last five years.

LED televisions use the same motion processing technology as LCD panels, with all panels currently on the market using 100Hz refresh rates. As LED televisions are leading the market in technological innovations, they will usually employ the latest generation of motion processing technology available, making them a good choice for watching fast motion video.

POWER CONSUMPTION

Most LCD televisions require a single fluorescent backlight to be lit. Plasma televisions, on the other hand, require every sub-pixel to be lit individually. When you compare screens of equal size plasma televisions consume more power than their LCD counterparts. A 42 inch LCD consumes around 200 Watts in normal use while a plasma panel will consume approximately 300W. In a year of use this means the power bill for running a plasma will be 50 per cent higher than an equivalent LCD panel. Also consider the power-saving features of individual models — power-reducing features may make a plasma screen just as affordable in the long term.

LED television screens offer significant power savings over both LCD and plasma televisions. Energy-efficient backlighting allows LED televisions to have energy consumption of up to 40 percent less than LCD televisions and significantly less than a plasma screen.

LIFESPAN

In the past, plasma panels suffered from a short life-span before they lost significant amounts of brightness and image quality degraded. This has been overcome in recent plasma generations, with manufacturers rating their screens with a half-life of 60,000 hours. This means that after 60,000 hours of use, the screen’s brightness will degrade by half — and with five hours of use per day this amounts to approximately 33 years. Put simply, plasma screens no longer suffer from a short lifespan.

The lifespan of an LCD television depends on the life of its backlighting bulb. These bulbs are often rated to above 60,000 hours in regular fluorescent-lit LCD panels, whereas new LED-backlit televisions have expected lifespans of over 100,000 hours. It is important to note that the end of this lifespan does not necessarily mean the screen will stop working; it usually means that the backlight will be able to provide half the brightness of a brand new model.

Previously, plasma television screens were hounded by image burn-in issues. Leaving a static image on the screen for a long period of time (such as a computer’s desktop or a network broadcaster’s logo) led to the plasma cells retaining the image. Improvements in plasma technology, the addition of functionality like screensavers and image-shifting, as well as power saving shutdown features, means the issue of burn-in effectively no longer exists for new plasma televisions. LCD televisions do not experience any of the problems previously found in plasma TV technology.

PRICE vs SCREEN SIZE

More than any other determining factor, it is tempting to simply pick the cheaper of either a plasma or LCD television when considering any given size. For screen sizes below 42 inches, we believe LCD screens provide the best value for money. Contrast and brightness shortcomings are less apparent in smaller screen sizes, while you will also generally find LCD screens below 42 inch have a higher resolution than their plasma equivalents.

If you are considering a large screen — 42 inch and above — as your home theatre centrepiece, we highly recommend plasma technology. Plasma panels do have the edge in terms of contrast and overall picture quality at these sizes, and are often cheaper than an equally-sized LCD counterpart.

LED televisions are generally available in similar sizes to LCD televisions, with larger screens also available in premium models. LED televisions generally command a price 20 per cent above that of an LCD television featuring an identical screen size and similar specifications. But when making a buying decision based on upfront costs, it is important to consider the total cost of ownership over the life of the TV. LED televisions’ power-saving advantages make them attractive prospect for long-term use.

SCREEN DEFINITION

If you are a true videophile, keen to see every pixel of a 1080p source reproduced as is, then LCDs are seemingly the way to go. However, 1080p is quickly becoming standard, with many LCDs now featuring 1920×1080-pixel resolutions. Budget LCDs and plasmas on the other hand feature either 1366×768 or even 1024×768 (720p) resolutions. If you’re buying a screen 50 inches or larger, there’s now no reason to get anything less than 1080p.

Despite the current HD buzz, there is still very little content available in 1080p — especially when compared to the infinite amount of SD content like TV programs and DVDs. At present, Blu-ray, and some HD downloads, are the only sources that can do 1080p, and free-to-air is only 1080i.

But it isn’t all about the resolution – it’s not the pixels, it’s what you do with them. Most modern TVs, and even budget ones, will accept a 1080p input, and it depends on the quality of the scaler on-board as to how good a picture you’ll get. The big brands such as Panasonic, Sony, Samsung and LG usually have very good image processors that can resize the source content — whether it’s a DVD, Blu-ray or FTA — to the resolution of your screen without a problem.

CONCLUSION

No matter what screen technology you select, make sure you test it against its competitors – storefronts with multiple panels set up next to each other are great for this purpose — and be sure you are able to adjust settings to your own liking in store. While the specifications of a TV and the screen technology employed are important buying considerations, it is advisable to not buy blind and physically confirm that the picture and other elements of the television are satisfactory.

The two different camps of flat-panel display standard will, of course, promote and market the advantages of their own technologies and the deficiencies of the other. But which type of display, plasma or LCD, is better? And which will give you the most value for money?

For now, I’m going with a full-HD plasma television for size 42″ and above, LCD television for any size less than 42″.

This article was originally provided by Simon Lakey for IntegratedTechnologiesAustralia.com.au