Are There Limits to What Video Calibration Can Fix?

Written by the ISF Forum Library Community
Friday, 18 May 2007

[ Q ] How do I know if my HDTV is going to benefit from calibration? For example, will it change the fact that my picture breaks into multi-colored blocks every once in while? What about the fact that in some dark scenes I can see a greenish tint?

[ A ] While calibration is the only way to ensure you are enjoying the best possible picture quality your TV can deliver, it's not a cure-all for every possible problem with your display or its associated video sources.

For example, the fact that your HDTV occasionally pixellates is likely a reception issue, or perhaps a sign of excessive signal compression -- but it almost certainly isn't a video calibration problem. On the other hand, the green tint you're seeing in dark picture areas would likely be eliminated after calibration, as it sounds like the grayscale is skewed toward green.

One of the questions we hear most frequently is: "Will calibration improve my standard-definition picture quality?"

The answer to that one is mixed -- calibration will improve contrast ratio, grayscale accuracy, color balance and reduction of edging artifacts for SD signals coming into your display. But the most common issue with standard-definition sources -- particularly from cable and satellite systems -- is that these SD signals have been aggressively over-compressed, with the result that significant parts of the video signal missing. Another issue is the quality of the scaling circuitry included in your cable or satellite box or within the HDTV itself.

So, if you're dealing with a seriously compromised SD signal, proper imaging will not be possible -- through no fault of the display, or how it has been calibrated.

Elsewhere, there might also be serious issues arising from your viewing environment, or you may have a problem that requires a service call. In both cases, a calibrator should be helpful in steering you toward room adjustments, or perhaps to recommend a reliable local repair company or technician -- in some cases, calibrators are also authorized service techs for certain brands.

Your best bet is to contact a qualified ISF Forum calibrator to discuss your specific questions and issues in more detail.

Contributions to this FAQ article were made by the following ISF Forum calibrators:
CinemaQuest , Dave Hancock, Home Theater Calibration, Precision Video

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