LCD : NEW GUIDELINES










Walk into a TV showroom and the dazzling display of screens can be tempting. However, the wide variety and the salesperson's spiel can confuse rather than ease your decision. Here are 6 features you should consider before buying an LCD TV.




RESOLUTION

This is the number of pixels per square inch or the number of rows and columns used to create the display. Most high-definition (HD) TVs have a resolution of 1920x1080, referred to as 1080p. The 'p' indicates progressive-scan format (every line of information is shown), which delivers a smoother image that stays sharp during motion.   You'll enjoy high resolution most if the video source is also HD, such as Blu-ray, a laptop (with a 1080p output) or the latest HD channels.

BRIGHTNESS

Luminance is the amount of light emitted by the screen and is measured in candelas per square meter (cd/m2). A brightness rating of 550 cd/m2 or higher is good, but it is better if you check this feature yourself while buying the TV.   Do so under various conditions (all lights on, only a lamplight, etc) to see that the image doesn't seem washed out. It's best if there is a screen sensor that adjusts the brightness of the screen according to the ambient light in the room.

CONTRAST RATIO

This refers to the difference in intensity of the brightest and the darkest colours. Most TV makers quote high numbers for dynamic contrast ratio, which is measured by obtaining the values of pure white and pure black separately.   However, do not be impressed with this as it isn't a true representative. A better one is the standardised ANSI/native/ static contrast ratio, which measures the difference between black and white simultaneously. TV makers rarely mention this as it is a smaller figure.


PORTS AND VIDEO INPUTS


Ensure your LCD TV has a composite video input as well as HDMI and USB ports. The video input is for attaching cable or satellite modems, while the HDMI (high-definition multimedia interface) is for hooking multimedia devices that require faster transmission, such as gaming consoles and laptops.   A USB port will help you connect a pen drive, portable music player or mobile phone directly to your TV. So, check that it can play most video and audio formats.


ASPECT RATIO


Aspect ratio is the ratio of the screen's width to its height. The wide screen 16:9 is great for movies. However, most TV transmissions are in the 4:3 format, which can cause picture distortion. To avoid this, ensure that the TV allows you to select screen formats, such as normal, wide and zoom.   You will also come across colour gamut enhancers, which means that the TV can produce a wider range of colours as well as allow you to adjust the vividness.


RESPONSE  TIME AND REFRESH RATE


The response rate is the minimum time necessary for a pixel to change its colour or brightness. Most HDTVs have a time of 8 ms (millisecond), 4 ms or 2 ms. A lower number is better as it reduces 'ghosting' or blurring and shows a crisp transition to the new colour.



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