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Calibrating Video Performance

Now it's time to start calibrating. There isn't space to go into the full setup routine here, but I'll touch on the general approach that you want to take.

The first calibration you want to make is to your set's brightness and contrast levels. Basically, you want to adjust your set to get the deepest possible blacks while still maintaining detail in the shadows.

You begin by turning down the color all the way, so that you have a true black and white picture. Now you want to display a pattern of black and gray bars, which is called a PLUGE (for picture line-up generation equipment) pattern´. With the PLUGE pattern onscreen, adjust the set's brightness control to make the pure black bar as dark as possible, and then adjust the contrast control so that the differences between the other dark bars are just barely visible. On most sets, adjusting either the brightness or contrast control effects the other adjustment; you have to adjust these two controls in conjunction with each other.

Next, you want to increase the color control until you have a more appropriate color level, and then adjust the tint control for a natural flesh tone level. When using the AVIA or DVE discs, you perform both these adjustments using a series of color filters. With a pattern of color bars displayed onscreen, you hold the color filter up to your eyes and then adjust the color and tint controls accordingly. A blue filter is used to adjust the overall color level; red and green filters are used to calibrate proper tint. Note that most viewers tend to set too high a color level; this is where using a calibration disc and the proper test pattern is a big help.

After you've adjusted the color and tint, you can adjust your set's sharpness level. This is a tricky adjustment because most viewers tend to tweak the sharpness control up too high. When the setting is too sharp, the edges are artificially enhanced, which means you'll see ringing or ghosting around some hard-edged objects. Set the control too soft, and the picture starts to look fuzzy. You want to strike a balance somewhere in the middle.

If your set has pro-level adjustment controls, or if you have access to your set's service menu, there's another level of adjustment you can and should make. This adjustment involves your set's grayscale setting, which determines the set's light intensity. Because gray is created from a mix of red, green, and blue, you must set the color gamma levels for each of these three colors to match industry specifications.

Grayscale performance is measured in terms of IRE, which is a unit defined by the Institute of Radio Engineers. Black is defined as 7.5 IRE, and peak white is 100 IRE. The transitions between these two extreme comprise the grayscale. To adjust the grayscale to its proper levels, fine adjustments have to be made to the red, green, and blue color gamma levels. It's a tricky calibration, best done using professional color analyzer equipment. You can try this on your own (if you can access the service menu), but it's an easy calibration to mess up. (If you do decide to make this adjustment yourself, write down the current settings before you make any adjustments; this way, if you mess anything up, you can always return to the original settings.)

Finally, if your television is a CRT-based device, you'll need to properly converge the picture tube (or tubes, in the case of a projection set). This procedure entails displaying a test grid and adjusting each line of the grid until it's a perfect white, with no color fringing. Some sets have built-in convergence patterns; you can also find similar patterns on the AVIA and DVE discs.

When you're done making all these adjustments, you may be surprised at how your picture looks. It will probably look a little darker than you're used to, but that's the way it should look. Remember, the manufacturers (and retailers) really pump the brightness and color settings on the showroom floor; a properly calibrated picture is less bright and has more natural color levels than what you saw in the store.

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