Resolution - the difference between 720p and 1080i

Photo: Samsung

These numbers seem to be on the lips of every television salesman nowadays, so understanding what they mean would probably save you some time while discussing a potential purchase.

Numbers (720 or 1080) represent the number of pixels that your HDTV screen has. Since 720 or 1080 doesn't mean how many pixels your screen has in total but the number of 'lines' of pixels.

In a nutshell, the higher the number would mean more pixels and therefore an increase in the TV's ability to display more detailed images.

The letters "p" and "i" mean "progressive scan" and "interlacing" respectively. To make things simple, remember that progressive scan (p) is the better technology compared to interlacing (i), and results in a smoother picture.

If you're looking for an HDTV to play games in high-definition (such as those on the PS3) or to watch Blu-Ray movies, go for the highest available resolution at 1080p.

Should that TV set be one for Junior to replace that broken old CRT, getting one that is 1080i or even 720p would be pretty sufficient.

What is "HD Ready" and "Full HD"?

You might also come across terms like "HD Ready" and "Full HD" at stores. While figures like 1080p is an industrial standard measurement, terms like "HD Ready" are not.

A 1080i set can be considered "Full HD" in some countries, and all TVs which are able to display HD images (from the lower-end 720p to the best 1080p models) are all "HD Ready".

Before sinking in your hard-earned dollars into a new HDTV, make sure you get the actual industry standard HD resolution specifications from the retailer and check that against your needs.

Contrast Ratio

This term refers to how well an HDTV is able to display the colour black. There is no industry standard for contrast ratio measurements, but in general, plasma TVs have the best contrast ratio, followed by LED TVs and finally conventional LCDs.