What is video calibration (or, why should I care)?
Television is an encode/decode system and like other systems of that type, proper alignment of various settings is critical to proper performance and viewer enjoyment. To put it in audio terms, the LP record can only be played back correctly at 33 1/3 rpm! Any other playback speed is simply wrong, rather than an expression of preference.
ISF calibration (as the process is known) is the correct alignment of certain variables in the playback device (the TV, video processor/projector or monitor) to match those same characteristics in the encode device (the NTSC or ATSC encoder and monitor at the source). And a typical home theater adds additional variables of sources, cables, switchers and environment to the mix of things to account for, what is now, a system alignment. The variables we look at are: White level, black level, saturation, hue, edge enhancement, color temperature, grayscale tracking and color decoder output levels. Other parameters that effect picture quality are: Focus, geometry and convergence issues, are not, strictly speaking, calibration. All types of video technologies can benefit from proper calibration for best picture quality and enjoyment.