JUDGING PICTURE QUALITY

The most difficult thing to judge when shopping for a TV is how good the picture looks. Good is a subjective term, so relying on the judgment of reviewers (such as CNET) may not get you exactly what you want. Then again, many reviewers scoff at the kinds of pictures that impress TV shoppers in the store. In this section, we'll offer some tips on become a more discerning viewer and what separates good pictures from the rest.

The wall of tubes

Most electronics stores show their televisions on a big wall, fed by the same video signal split a hundred times. Although bright lights, suspect salespeople, and a lack of remote controls will probably make any picture-quality judgment difficult, here are a few things to look for on the wall.

• Don't fall for brightness. Almost every television on the sales floor is set to the brightest picture settings, so try to get the salesperson to reduce the controls of the TVs you're comparing. You want the pictures--not necessarily the controls--to be roughly equal in brightness, contrast, and color.
• Go out of the light. Few living rooms are as well lit as the sales floor, so see if the salesperson can reduce the amount of light shining on the picture. If nothing else, try to shade the screen if light is shining directly on it.
• BYO DVD. If you have a DVD that you're familiar with, see if you can use it instead of the TV signal that's normally shown. Aside from HDTV, which isn't very portable at the moment, DVD provides the best picture a television can display, so it makes for a good reference from which to judge.
• Try all the picture modes. Many sets come with numerous picture presets, such as Movie and Sports, that radically affect how the image appears. After you peruse the manually adjusted pictures, try the different presets and modes to see which ones look best.

Features that enhance picture quality

Normal analog TVs, as opposed to digital TVs, have just a few factors that affect picture quality. Look for these features or characteristics and disregard other features that sound good on the surface but in reality are just marketing ploys. Naturally, there are other important factors we can't cover here, but this should get you started.

• Comb filter. If a television does not have a comb filter, its resolution will be limited to about half the full potential of DVD. Most sets with comb filters can provide all of the resolution of DVD. The types of comb filters you'll see advertised, in order of lower to higher quality, include two-line, three-line, digital, and 3D YC varieties. They provide incremental improvements in performance, especially in reducing rainbows that can appear in fine detail, such as a talking head's suit coat. Comb filters affect only composite-video or RF connections.
  
  
• Color-temperature settings. Many televisions have presets for color temperature, which is basically the color of gray. A neutral gray is ideal, but most TVs have an extremely blue gray to make the picture brighter in the store. TVs with color-temperature presets allow you to choose the color of gray; generally, you'll want the reddest or lowest setting available.
  
  
• Color decoder. Most TVs' color decoders are set to be too red to counteract the blue color temperature described above. TV makers don't advertise accurate color decoders, so you'll have to judge for yourself or trust a reviewer. In the store, look for pale skin tones that don't appear too flushed and reds that don't bleed into other colors or otherwise seem more intense than the rest of the palette.
  
  
• Geometry and convergence. Most TVs get bumped around in shipping, so it pays to check convergence before you take yours home--or at least before the warranty expires. Look toward the edges of the screen, preferably with graphics or other straight lines (CNN's crawling ticker works great), and see if the lines are actually straight. To check convergence, look at the corners with white material, preferably lines again, and see if faint halos of color surround the white.
  
  
• Calibration You'll often see CNET reviews mention calibration or the ISF. When they review high-end televisions, our writers access a service menu using codes that aren't available to the average consumer, and they use that menu--along with specialized equipment such as color analyzers--to calibrate the TV for optimal display of video according to NTSC standards. The Imaging Science Foundation, or ISF, has a program that trains professionals to calibrate televisions, and for a few hundred dollars, you can retain an ISF professional to adjust your TV.
  
  Alternatively, you can use a calibration DVD to help you adjust the television. These discs, such as Ovation Software's Avia, Joe Kane's Digital Video Essentials, and Sound & Vision's Home Theater Tune-Up, show you how to optimize your set within the limits of the standard user-accessible menus.