Setting the Backlight Control
What is the proper way to set an LCD TV's backlight? I have two calibration discs, and neither of them address this issue.
An LCD TV's backlight control is independent of all other picture controls; it simply determines how much raw light the TV produces. Before setting the backlight, you must first set the brightness (black level) and contrast (white level) controls, which is best done with the backlight at a fairly high setting so you can clearly see the images used to set the black and white levels.
Once the brightness and contrast controls are set correctly, you can then adjust the backlight control depending on your personal taste and the amount of ambient light in the room. If you like a bright image and/or there's lots of room light, you can set it fairly high. On the other hand, if you prefer a darker image and/or there is little or no room light, set the backlight lower. Once you have the backlight where you want it, display the brightness and contrast patterns again to make sure they are still correct, which they should be.
When I review an LCD TV, I set the brightness and contrast with the backlight fairly high, then turn it down so the peak-white level (the amount of light when displaying a 100-percent white window) measures around 30 foot-lamberts in a dark room. Of course, that requires an expensive light meter, so for most folks, adjusting the backlight to their personal preference in a given amount of room light is the best way to go.
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